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    [Illustration: PERCIVAL LOWELL AGE 61
    From a silver point portrait begun before his death and finished
    afterwards by Eccolo Cartollo]




                              BIOGRAPHY OF
                            PERCIVAL LOWELL


                                  _By_
                           A. LAWRENCE LOWELL


                                NEW YORK
                         THE MACMILLAN COMPANY
                                  1935

                         _Copyright, 1935, by_
                         THE MACMILLAN COMPANY.

All rights reserved—no part of this book may be reproduced in any form
without permission in writing from the publisher, except by a reviewer
who wishes to quote brief passages in connection with a review written
for inclusion in magazine or newspaper.

                         _Set up and printed._
                      _Published November, 1935._

                PRINTED IN THE UNITED STATES OF AMERICA
                      NORWOOD PRESS LINOTYPE, INC.
                         NORWOOD, MASS., U.S.A.




                                PREFACE


If genius is the capacity for taking infinite pains, Percival Lowell
possessed it abundantly from his study of Esoteric Shinto, in his
earlier life in Japan, to his great calculation of the position and
orbit of an unknown planet beyond Neptune, at the close of his life. In
determining facts he was thoroughly and rigidly scientific, leaving
nothing unexplored that bore upon the subject; and in his astronomical
investigations it became clear to him that better methods of doing it
were required. At the outset, therefore, he set up his Observatory in an
atmosphere steadier than that where the older telescopes, and almost all
of those then in existence, did their work; thus seeing much not visible
elsewhere.

But in addition to industry he had an inflammable intellect, easily
ignited by any suggestion or observation, and when alight glowing in
intensity until the work was done. He had also a highly vivid
imagination, compared with many men of science who proceeded more
cautiously; and hence he sought, not only to ascertain new facts, but to
draw conclusions from them more freely than is customary with experts of
that type. This he felt had often been true of those who made advances
in scientific thought, and he regarded himself as standing for a time
somewhat apart from most men in his own field. Such an attitude, and the
fact that he had taken up observational astronomy in middle life,
unconnected with any other scientific institution, tended to make many
professional astronomers look upon him askance. So he plowed his own
furrow largely by himself in the spirit of a pioneer, and this little
volume is an attempt to tell what he accomplished.

The writer is very grateful to the Houghton, Mifflin Company, the
Macmillan Company, The Atlantic Monthly, Rhodora, the Scientific
American, and Miss Katharine G. Macartney (on behalf of Mrs. George
Gould) for permission to quote, sometimes at great length, from books
and articles by and about Percival. The writer desires also to express
his deep obligation to Mr. George R. Agassiz, his brother’s intimate
friend and helper, to Dr. Vesto Melvin Slipher, Dr. Carl O. Lampland and
Mr. E. C. Slipher of the Lowell Observatory at Flagstaff, for reading
the manuscript and giving advice; and to Professor Henry Norris Russell
of Princeton University, for his kindness in not only doing this, but
for writing the two appendices that follow this volume. Without their
help the astronomical part of this book would have been sadly defective.
They have pointed out advances in knowledge that have made certain of
Percival’s opinions, particularly earlier ones, no longer tenable. Some
of these he changed during his lifetime, others he would have changed
had he lived to see the more ample facts since known. Nor is this a
criticism of his work, for astronomy has been advancing rapidly of late;
and when that is true no man can expect all his views, even if accepted
at the time, to endure. Change in opinions is the penalty of growing
knowledge. It is enough that a man has helped to push knowledge and
thought forward while he lived, and this Percival, with the exhaustless
energy of his nature, certainly did.

                                               Boston, October 21, 1935.




                                CONTENTS


  CHAPTER                                                            PAGE
  I Childhood and Youth                                                 1
  II First Visit to Japan                                               8
  III Korea                                                            13
  IV His First Book, “Chosön”                                          17
  V The Coup d’Etat and the Japanese March to the Sea                  20
  VI The Soul of the Far East                                          29
  VII Second Visit to Japan                                            41
  VIII Japan Again—the Shinto Trances                                  52
  IX The Observatory at Flagstaff                                      61
  X Mars                                                               76
  XI The Permanent Observatory—Interludes and Travels                  92
  XII Illness and Eclipse                                              98
  XIII Mars and Its Canals                                            107
  XIV The Solar System                                                120
  XV Later Evolution of the Planets                                   136
  XVI Interludes                                                      145
  XVII The Effect of Commensurate Periods                             157
  XVIII The Origin of the Planets                                     168
  XIX The Search for a Trans-Neptunian Planet                         176
  XX Pluto Found                                                      195
    Appendix I Professor Russell’s Later Views on the Size of Pluto   203
    Appendix II The Lowell Observatory by Professor Russell           206




                             ILLUSTRATIONS


  Percival Lowell, Age 61                                  _Frontispiece_
  Percival Lowell and His Biographer                        Facing Page 4
  Percival Lowell and the Members of the Korean Embassy                16
  Observing and Drawing the Canals of Mars                            116
  Gaps in the Asteroids and the Rings of Saturn                       166
  Predicted and Actual Orbits of Pluto                           Page 199




                               BIOGRAPHY OF
                             PERCIVAL LOWELL




                               CHAPTER I
                          CHILDHOOD AND YOUTH


The particular assortment of qualities a man inherits, from among the
miscellaneous lot his ancestors no doubt possessed and might have
transmitted, is of primary importance to him. In this Percival Lowell
was fortunate. From his father’s family he derived a very quick
apprehension, a capacity for intellectual interests, keen and
diversified, and a tireless joy in hard mental labor; while from his
mother’s people he drew sociability, ease of companionship and charm;
from both families a scorn of anything mean or unworthy, a business
ability and the physical health that comes from right living. His life
is the story of the use he made of these heirlooms.

The son of Augustus Lowell and Katharine Bigelow (Lawrence), Percival
Lowell was born in Boston on March 13, 1855, at 131 Tremont Street where
the Shepard stores now stand. The region was then residential, and his
parents went there so that his mother might be near her father, the Hon.
Abbott Lawrence, whose house was on Park Street, now the main portion of
the Union Club. He had fallen ill since his return as Minister to
England, and was now failing fast. Percival was her first-born, but
others followed rapidly, involving removal to larger quarters; first to
Park Square, and then to 81 Mount Vernon Street, where even the games of
little boys were tinged by the overshadowing events of the day,—the
drilling and the battles of the Civil War. He went to a dame school kept
by Miss Fette; and being always a good scholar learned what he should;
for he developed normally. After infancy the summer was spent at Beverly
in the pleasures and occupations of early childhood.

But in the spring of 1864 there came a sudden change. His mother was far
from well, and losing ground so fast that his father was advised to take
her abroad for a complete change as her only chance,—a heroic remedy
which proved in time successful. So the family sailed in the _Africa_, a
paddle-wheel steamer of 2500 tons with the sails of a full-rigged
ship,—the father with an invalid wife, four children aged from nine to
two, a nurse sea-sick all the time; and in addition the care of three
more children of a friend in Europe, with a nurse who was well, but
bereft of sense. However, they arrived safely, spent the summer in
England, and, as all Americans did in those days, went to Paris for the
winter.

Here Percival began a life different from that of his contemporaries at
home; for with his younger brother and his cousin, George P.
Gardner,—one of the children who had crossed with him on the _Africa_—he
went to a French boarding school kept by a Mr. Kornemann. We were
allowed to come home for Sundays, but spent the rest of the week at the
school,—a very wise arrangement; for, although there were some English
boys, the atmosphere was French, and we learned the language easily, by
the native method of teaching it. To Percival this was a great benefit
throughout his life.

Two winters were spent in this way, the intervening summer being passed
by the family in travel. In the spring of 1866 his parents proposed to
go for a few weeks to Italy, and take the children with them; but
Percival was so ill at ease in travel that he was left at the famous
boarding school kept by the Silligs at Vevey. Although in mature life a
constant traveller, this event was not out of character, for not being
yet old enough to enjoy the results of travel, or feel the keen interest
in them later aroused, he was too restless to find pleasure in long
journeying without an object. On their return from Italy the family
picked him up and went to Germany, where they were caught by the seven
weeks’ war with Austria. When it broke out they were at Schwalbach in
Nassau, one of the smaller states that took sides against Prussia.
Percival always remembered vividly what he there saw, exciting enough
for a small boy; the sudden clatter of a galloping horse, as a man in
civilian dress passed the hotel up a small lane to the left. It was the
burgomaster carrying word of Prussian advance, followed quickly by the
sound of several more horses, and three videttes in blue galloped past,
turning up the main road in front of the hotel where they supposed the
burgomaster had gone. Up the road they went and disappeared round a turn
to the left at the top of the slope. Scarcely had they vanished when a
squad of green-clad Nassau infantry appeared, and following half-way up
the hill hid behind a wood pile. It was not long before the Prussian
videttes, having failed to find the burgomaster, came into sight again,
leisurely walking their horses down the road. When abreast of the wood
pile the Nassau squad stole out, firing from the hip in the manner of
the day. Whether they hit anyone we never knew, but the enemy was wholly
dispersed, for one of the horsemen wheeled up the hill, another spurred
his horse down past the hotel, and the third jumped his over the wall
into the garden of the baths. That afternoon a Nassau regiment marched
into the town and bivouacked in the streets, leaving in the morning to
be replaced later in the day by a Prussian regiment, which in its turn
marched off to its rendezvous near Kissingen.

By the end of the summer of 1866 Mother was well enough to go home, and
the whole family sailed for Boston. Percival’s education there was of
the ordinary classical type preparatory for college, for one year at a
school kept by a Mr. Fette, brother of his teacher in childhood, and
then for five years in that of Mr. George W. C. Noble, whose influence,
both by teaching and character, was strong with all boys capable of
profiting thereby. Percival was always near the top of his class,
especially in the Classics, which he acquired so easily that while
playing with a toy boat, in a shallow pond made by the melting snow on
the lawn at Brookline, it occurred to him to describe an imaginary
shipwreck thereof; and he did so in some hundreds of Latin hexameter
verses.

    [Illustration: PERCIVAL LOWELL
    And His Biographer]

In the spring of 1867 Father bought the place at the corner of Heath and
Warren Streets in Brookline, where he lived until his death in 1900; and
where his last child, Amy, passed her whole life. Here Percival spent
his boyhood, summer and winter, until he went to college, enjoying the
life and sports of the seasons; and, in fact, he was a normal boy like
his comrades, only more so. During the earlier years Father drove us
into town and out again each day, he going to his office and the
children to school. On the road he talked on all subjects and we learned
much in this way. Somehow he made us feel that every self-respecting man
must work at something that is worth while, and do it very hard. In our
case it need not be remunerative, for he had enough to provide for that;
but it must be of real significance. I do not know that he ever said
this formally, but, by the tenor of his conversation and his own
attitude toward life, he impressed that conviction deeply upon the
spirit. From his own active and ambitious nature, Percival little
required such a stimulus; and, indeed, he struck out an intellectual
path of his own in boyhood. He took to astronomy, read many books
thereon, had a telescope of his own, of about two and a quarter inches
in diameter, with which he observed the stars from the flat roof of our
house; and later in life he recalled that with it he had seen the white
snow cap on the pole of Mars crowning a globe spread with blue-green
patches on an orange ground. This interest he never lost, and after
lying half-dormant for many years it blazed forth again as the dominant
one in his life, and the field of his remarkable achievements.

The two years of school in Paris certainly had not retarded his
progress, if, indeed, the better European discipline had not advanced
it; for he could have been prepared for college at sixteen, but it was
thought well to extend the time another year and fill in with other
things. Strangely enough, Mr. Noble thought him not so strong as he
might be in two subjects where he later excelled,—English Composition
and Mathematics,—and in these he was tutored the year before entering
college. Later he thought he had been misjudged, but one may suspect it
was rather because his interest in these matters had not been aroused.
The capacity was there but not yet awakened. However, he entered college
in the autumn of 1872 not only clear but with honors in Mathematics. In
fact he studied that subject every year in college, took second-year
honors in it, and Professor Benjamin Peirce, the great mathematician,
spoke of him as one of the most brilliant scholars ever under his
observation, hinting to him that if he would devote himself thereto he
could succeed him in his chair. Yet it was by no means his sole field of
knowledge, for he elected courses also in the Classics, Physics and
History, doing well enough in all of them to be in the Φ Β Κ and have a
Commencement part. An impression of his versatility is given by the fact
that in his senior year he won a Bowdoin Prize for an essay on “The Rank
of England as a European Power from the Death of Elizabeth to the Death
of Anne,” and spoke his part on “The Nebular Hypothesis.”

Yet he was no recluse; for he was constantly that year at dancing
parties in Boston; and, being naturally sociable, and strongly attached
to his friends, he made many in college. With Harcourt Amory, his
Freshman chum, he went abroad, after graduating in 1876, and spent a
year in Europe. The young men went to London with letters that brought
them into delightful society there, and they travelled over the British
Isles and the Continent. It was mainly the _grand tour_; but although he
wrote many letters, and kept a journal, these, so far as preserved,
reveal little of his personality except a keen joy in natural beauty and
a readiness in acquaintance with people casually met. Alone, he went
down the Danube, and tried,—fortunately without success,—to get to the
front in the war then raging between Servia and Turkey. With Harcourt
Amory he went also to Palestine and Syria, at that time less visited
than they are to-day; but for this part of his journey, where it would
be most interesting, his journal, if written, is lost. His love of
travel had fairly begun.




                               CHAPTER II
                          FIRST VISIT TO JAPAN


In the summer of 1877 he came home; and, having no impulse toward a
profession, he went into the office of his grandfather, John Amory
Lowell, where he was engaged in helping to manage trust funds. In
this,—in learning the ways of business, for a time as acting treasurer,
that is the executive head, of a large cotton mill, and withal as a
young man of fashion,—he spent the next six years. With money enough for
his wants, never extravagant, and with the increase that came from
shrewd investment, he felt free in the spring of 1883 to go to Japan to
study the language and the people. Both of these he did with his
habitual energy, learning to speak with great rapidity, meeting socially
Japanese and foreign residents in Tokyo, and observing everything to be
seen. His own view of the value of travel and study is given in a letter
to a sister seven years his junior, written apparently in the preceding
summer when she was in Europe.[1] “I am very glad,” he says, “that you
are taking so much interest in studying what you come across in your
journey and after all life itself is but one long journey which is not
only misspent but an unhappy one if one does not interest one’s-self in
whatever one encounters—Besides, from another standpoint, you are
storing up for yourself riches above the reach of fickle fate,—what the
moths and rust of this world cannot touch. You are making, as it were, a
friend of yourself. One to whom you can go when time or place shall
sever you from others, and the older you grow, sweet puss, the more you
have to depend upon yourself. So, school your mind then, that it may
come to the rescue of your feelings—and a great thing is to cultivate
this love of study while yet you are happy. For if you wait until you
need it to be happy, you will, with much more difficulty, persuade
yourself to forget yourself in it—Now as to particulars, you need never
worry yourself if you do not happen to like what it is orthodox to
prefer. You had much better be honest with yourself even if wrong, than
dishonest in forcing yourself to agree with the multitude. That is, the
opinion one most commonly hears is not always the opinion of the best.
And again, always be able to give a reason for what you think and, to a
great extent, for what you like.”

At once he was fascinated by Japan, its people, their customs, their
tea-houses, gardens and their art. Much of this was more novel to his
friends at home when he wrote about it than it would be now; although
even at that time he saw how much Tokyo had already been influenced by
Western ideas and habits. He kept his attention alert, observing,
studying, pondering everything that he saw or heard. In fact, within a
fortnight he lit upon two things that later led to careful examination
and the writing of books. In a letter to his mother on June 8, in
dealing with differences that struck him between the people of Japan and
occidentals, he writes: “Again, perhaps, a key to the Japanese is
impersonalism. Forced upon one’s notice first in their speech, it may be
but the expression of character. In the Japanese language there is no
distinction of persons, no sex, no plural even. I speak of course of
their inflected speech. They have pronouns, but these are used solely to
prevent ambiguity. The same is true of their genders and plurals. To
suppose them, however, destitute of feeling, as some have done, I am
convinced would be an error. The impersonalism I speak of is a thing of
the mind rather than the heart. I suggest rather than posit.” In a
letter, three days later, he tells of a friend whose jin-riki-sha man’s
wife had the fox disease, “a species of acute mania supposed by the
people to be a bewitchment by the fox. As the person possessed so
regards it and others assist in keeping up the delusion by interpreting
favorably to their own views, it is no wonder that the superstition
survives.” Some years later an unexpected sight of a religious trance on
Mount Ontake gave rise to a careful study of these psychic phenomena.
Well did Pasteur remark that in the fields of observation chance favors
only the minds that are prepared.

He hired a house in Tokyo, set up his own establishment as if he had
been born and bred there, and after three weeks on shore wrote: “I am
beginning to talk Japanese like a native (of America), and I take to ye
manners and customs of ye country like a duck to the water.” He stayed
enjoying the life, and the many friends he made, until the middle of
July, when, with Professor Terry of the University, he started on a trip
across the mountains to the other side of the island. The journey was
hard, and at times the food and lodging poor. “Think,” he writes, “of
the means of subsistence in a land where there is no milk, no butter, no
cheese, no bread, almost no meat, and not over many eggs. Rice is the
staple article of food, then vegetables, eggs and fish; the last two
being classed as the food of the richer, and most eaten in the greater
centres. Some country people are so poor that they have not rice, and
eat barley instead. It is considered a sign of poverty to be without
this universal article of diet, but in travelling about in
out-of-the-way corners one meets with such places. I have myself lit
upon such at the noon-day halt but have never been obliged to spend the
night there.” But the scenery was fine, and the people unchanged by
contact with the foreigner. He noted archaic devices still in use for
pumping and boiling water; yet, in visiting a ruined castle, he saw that
while the interior of the country had as yet been little affected by the
impact of the West its political condition had been transformed with
amazing speed. “We mounted through some seven barnlike rooms, up
Japanese ladders to the top story. Sitting by the window and looking at
the old feudal remains below, the moat with its stagnant slime and the
red dragon flies skimming its surface, the old walls, the overgrown
ramparts where now the keeper tries to grow a crop of beans, all tended
to carry my thoughts back to the middle ages, or was it only to my own
boyhood when the name _middle ages_ almost stood for fairy land? And yet
all this had been a fact, even while I had been dreaming of it. My
dreams of Western feudalism had been co-existent with Eastern feudalism
itself. So it was only eleven years ago that the last Daimio of the
place left the castle of his ancestors forever.”

From his journey across Japan he got back to Tokyo on August 13th, where
a surprise and an opportunity awaited him. On the very evening of that
day he was asked to accompany a Special Mission from Korea to the United
States as its Foreign Secretary and Counsellor. About this Dr. W.
Sturgis Bigelow wrote to Percival’s father:

  “After two days of unconditional refusal and one of doubt Percy has
  finally yielded to the wishes of the U. S. Legation here and accepted
  the position of Foreign Secretary and General Counsellor to the
  Embassy sent from Korea to the U. S.

  “The position practically amounts to his having complete charge and
  control of the most important legation from a new country that has
  visited the U. S. since the opening of Japan. The U. S. authorities
  here are greatly pleased at having secured so good a man, as is
  natural. There were many applicants for the place.”

He goes on to say the hesitation was mainly due to anxiety to what his
father would say, and adds:

  “He distrusts himself too much, he has great ability, he has learned
  Japanese faster than I ever saw any man learn a language—and he only
  needs to be assured that he is doing the right thing to make a success
  of anything he undertakes, whether science or diplomacy.”




                              CHAPTER III
                                 KOREA


It was the first diplomatic mission from the hermit kingdom to any
Western power, and they wanted someone with _savoir faire_ to look after
them. He accepted the post, landing in San Francisco with his charges on
September 2nd, and crossing to New York, where the Embassy was received
by President Arthur. After spending six weeks in the United States he
returned by the Pacific with the greater part of his colleagues,
reaching Japan in November. They felt grateful for what he had done, and
he was invited to go on with them to Korea as the guest of the King—a
chance not to be lost, so he went, and after sundry wearisome delays in
transit came to Söul, the capital of the Kingdom, just before Christmas,
1883.

Evidently he had not intended so long a sojourn and study as he was
destined to make, for in a letter to his mother on December the 20th,
just after landing at Chemulpo, the port of Söul, he writes: “I purpose
to study the land a little and then return overland either to Pusan”
(the Japanese treaty port at the extreme southern end of the peninsula)
“or after some travelling in the interior here, Gensan.” He had as yet
no idea of the impossibility of travel in Korea in the winter,
especially for an occidental, but he learned it the following day when
with much discomfort he went half way to Söul, the whole distance from
the port to the capital being twenty-seven miles. Another and stronger
reason for his prolonged stay was the hospitality tendered and the
solicitude for his comfort. At Nagasaki, where the ship stopped on the
journey from Japan, his Korean colleagues, observing his preference,
engaged a Japanese familiar with European cooking to become a member of
his household, and they brought along also chairs for his use. In the
letter to his mother just quoted he writes; “I think I shall either take
a house of my own or, perhaps better, have a part of a Corean’s to my
exclusive use.... I shall of course be asked to stay at our minister
Foote’s, but I shall fight shy of it in order to be less tied
politically.[2] You see there are national parties even in this small
state, and I think it best for me to be, at any rate at first, on the
cross benches. Out in the Far East the ministers of foreign countries
are always mixed up in national politics, and Corea is no exception to
the rule.” A shrewd observation in view of the fact that hardly a year
passed before there was bloodshed between the adherents of China and
Japan in the government, when the Japanese legation was attacked and
fought its way to the sea.

He found that there had been prepared for him a house, or rather group
of buildings forming a part of the Foreign Office, of which he was
formally a member as having been Counsellor to the Embassy to America.
“From the street,” he writes, “you enter a courtyard, then another, then
a garden, and so on, wall after wall, until you have left the outside
world far behind and are in a labyrinth of your own. Before you lies a
garden; behind another surrounded by porticoes. Courtyards, gardens,
porticoes, rooms, corridors in endless succession until you lose
yourself in the delightful maze.” He speaks of the painting of
landscapes on the walls, of a door cut out as a circle in the wall into
which fit two sliding panels beautifully painted on both sides. “Floor,
ceiling, walls all are paper. But you would hardly imagine that what you
tread upon, to all appearance square stone slabs, is oil paper so hard
as even in sounds under your footfalls to resemble flags.... Through the
thick sliding windows sifts the golden light into the room, and for the
nonce you forget that outside is the dull grey of a cloudy sky and a
snow decked land of a December afternoon.”

There he spent the winter under strangely favorable conditions; one of
the first men of European race to enter the country with an official
position and no official duties or restraints, and a couple of officers
detailed to care for him, without hampering him by constant attendance
on his movements. In fact he seems to have been more free than anyone in
the land. It was beneath the dignity of a higher official to go through
the streets except in a palanquin; and all others, save blind men, must
not be out of their houses after night-fall on pain of flogging. But
finding that to be carried squatting on the cold floor of a box two and
a half feet square was intolerable, he took to his feet; and, being an
official, he walked all over the city at any hour of the day or night,
without this foreign eccentricity shocking either the high or the lowly.
He was received in special audience by the King and the Crown Prince,
and later photographed them; was visited and entertained abundantly,
made many acquaintances and some warm friends. On February 2nd, he wrote
to his mother: “I think it will please your maternal ear to hear of the
esteem in which your boy is held and of the honors and great kindness
which are lavished upon him. On New Year’s Eve[3] he received some gifts
from the King, made on purpose for him, a description of which you will
find in a letter to Katie. They were accompanied by the wish on the part
of His Majesty ‘that in view of my speedy return, he hoped that I would
come back next year.’ I had informed them of my departure before long,
which they do not view favorably. I was also told that I was constantly
in the King’s thoughts. He is hospitality and kindness itself to
everyone. I have seen several houses of the highest nobles in the land
and there is none to compare with the establishment they have given me.
I have been consulted on foreign business, my requests for others
granted, talked to on home matters, in short I am looked upon as a
friend of the government and cared for in corresponding style.”

Delightful as the experience was, there came over him in time a desire
to go back to more familiar surroundings, and as spring approached he
spoke of his intention. They tried to dissuade him, and did induce him
to delay his departure; but at last he sailed with no little feeling of
sadness in leaving a country where he had been so kindly treated and
which he was never to see again. In a letter to his sister Bessie, on
February 17, not long before his departure he wrote: “I have already
taken fifty-three negatives of scenes in and about Söul, groups and
individuals. I am not only expected by the Coreans but urged to write a
book; but as I have a wholesome dread of publication I reserve my
decision. I am to send as a present to His Majesty a collection of my
photographs printed in Japan on my return.”

    [Illustration: PERCIVAL LOWELL AND THE MEMBERS OF THE KOREAN
    EMBASSY]




                               CHAPTER IV
                        HIS FIRST BOOK, “CHOSÖN”


He did write the book, and published it in 1885, under the title of
“Chosön—the Land of the Morning Calm—A Sketch of Korea” It is an account
of his personal experiences, under peculiarly favorable conditions, in a
land of Asiatic civilization almost wholly unknown to the outer world,
and as such it was, and after fifty years remains, a highly interesting
book of travel. Although there is too much clever play on words, a
natural temptation to a brilliant young writer, the story is graphically
told, with much appreciation and many poetic touches on men and scenes.
But the book is far more than this. It is a careful study of the land
and its people, their customs, ideas and manner of life. He describes
the geography of the country and of the walled capital, then little
known, the legends and government; the houses and mode of life of the
upper and lower classes, then sharply distinguished; the architecture,
landscape gardening and costumes, some of them very peculiar; for while
much of the civilization had been derived from China, and parts of it
bore a close relation to the conditions in Japan, it was in many ways
quite distinct and unlike anything else even in the Far East. Three
things struck him greatly, as lying at the base of the mode of life, and
these he called the triad of principles. They were the strange lack of
individual variation, which he called the quality of impersonality, of
which we shall hear more in connection with the Japanese; the
patriarchal system, with the rules of inheritance and the relation of
children to the fathers, which was carried very far; and the position of
women, in which the principle of exclusion, universal as it is in Asia,
was more rigidly enforced than elsewhere in the Far East.

He was also impressed by the absence of what we understand by religion,
in substance or in manifestation, unless the ethics of Confucius can be
so called. Save for a few monasteries there were no ecclesiastical
buildings, no temples, no services, public or observable. Buddhist
priests had long been excluded from the walled cities, and the ancient
cult that developed into Shinto in Japan died out or never developed. On
the other hand, there was a general belief in a multitude of demons,
some good, but, so far as they affected man, evil for the most part, and
kept away by trivial devices, like images of beasts on the roofs and
wisps of straw over the doors.

How he succeeded in acquiring all the knowledge set forth in the book it
is difficult to conceive, for he was there only about two months, came
with the slight knowledge of the language he could have picked up from
his colleagues on the Mission to America; and there were only two men,
it would seem, who could speak both Korean and any European tongue,—one
of them a German in the Foreign Office, and the other an English
schoolmaster who had been there but a short time. His chief source of
information must have come through people who spoke Korean and Japanese,
but his own knowledge of the latter was still very limited, for he had
spent only a few months in Japan, and his secretary, Tsunejiro Miyaoka,
afterward a distinguished lawyer in Tokyo, who knew English, was
desperately ill almost all the time he was in Korea. To have absorbed
and displayed so clearly all the information in “Chosön” makes that
work, if not one of his greatest contributions to knowledge, yet a
remarkable feat. Most books of travel are soon superseded, but this one
has a distinct permanent value, because the life he portrays, especially
that of the upper class, which was almost all connected with the holding
of public office, has been swept away, never to reappear, by the
conquest and ultimate incorporation of the country by Japan.




                               CHAPTER V
           THE COUP D’ETAT AND THE JAPANESE MARCH TO THE SEA


One more event in Korea interested him deeply, for it meant life or
death to some of his nearest native friends, and under the title of “A
Korean Coup d’Etat,” he gave a graphic account of it in the _Atlantic
Monthly_ for November 1886. Although not himself present, since it took
place in the December after he had left, it was not unconnected with the
Mission to America of which he had been a member; for the policy of
opening Korea to the world had not met with universal favor among the
officials, and all those who had gone on the Mission did not take it
very seriously. In fact the two groups rapidly drew apart, one side
seeking to extend foreign contacts and the use of foreign methods, the
other preparing to resist this. The latter began to strengthen
themselves by enrolling what they called a militia,—really a rough body
of men devoted to their interests,—until the progressionists, as their
opponents were called, saw that they would be crushed unless they struck
quickly. Among their leaders was Hong Yöng Sik, who had been especially
attentive to Percival during his stay in Söul, and he with his partisans
decided to get control of affairs by the method whereby changes of
ministry are often effected at a certain stage of political evolution,
that is, by removing objectionable ministers both from office and from
the world. The occasion selected was a banquet to celebrate the creation
of a post office, that institution being regarded as typical of good or
evil in foreign habits. The chief victim was wounded but not killed,
whereat the progressionist leaders, pretending to be alarmed for the
safety of the King, went to the palace and slew such of the leading
opponents as they could lay their hands on; but, having no troops, sent
in His Majesty’s name to ask the Japanese minister for the protection of
his force of one hundred and twenty guards. Not suspecting the real
nature of the disturbance, he complied, but was soon attacked by a body
of six hundred Chinese soldiers, naturally in sympathy with the
conservatives, and at their back the Korean militia. For two days the
Japanese guards held off the assailants with little loss to themselves
compared with that of their foes, until the King placed himself in the
hands of the Korean militia, when there was nothing for the Japanese to
do but to get back to their legation as best they could. The rest of the
tale he felt so much and told so well in the ephemeral form of a
magazine article that it is given here in his own words:[4]

Night had already wrapped the city in gloom, as the column defiled from
the palace gate into the black and tortuous streets of the town. No
resistance was made to their exit, for, under cover of the darkness, the
Korean soldiers had all secretly slipped away. A pall-like obscurity and
silence had settled over everything. It seemed the spirit of death. The
streets of Söul are for the most part hardly more than wide alleys,
crooked and forbidding enough in the daytime. Night converts them into
long cavernous passages, devoid of light, like the underground
ramifications of some vast cave; for, by a curious curfew law, they are
denied any artificial illumination. Through this sombre labyrinth the
Japanese column threaded its way, with nothing to light its path but the
reflection in the sky of fires in distant parts of the city,—a weird
canopy to an inky blackness. Before long, however, even night failed to
yield security from man. At the cross-roads and wherever a side-street
offered an opportunity for attack were gathered bands of braves, mixed
masses of soldiers and populace, who fired upon them or hurled stones,
according to the character of the individuals. Still they pushed
steadily forward, though utterly uncertain what they might find at their
journey’s end; for they had not been able to hear from the legation
since the attack on the palace, and were in grave fear for its safety.
As they came to the top of a bit of rising ground, they made out by the
lurid light of the fires their own flag, the red ball on the white
field, flying from its flagstaff, and thus learnt for the first time
that the buildings were still standing and in Japanese hands. As they
neared the legation the crowds increased, but, sweeping them aside, the
troops at length reached their destination at eight o’clock at night,
having been absent forty-eight hours.

That the legation was yet safe was not due to any neglect or forbearance
on the part of the Koreans. From the moment of the attempted
assassination of Min Yöng Ik, the city had fallen a prey to disturbances
that grew hourly graver and graver in character, and began to be
directed more and more against the Japanese merchants and traders
scattered through the town. Such of these as took alarm first hastened
to the legation for protection. In this way about seventy of them had
collected in the buildings, and they, together with the servants and a
score of soldiers that had been left there, had successfully defended
the place until the return of the troops. For two whole days the little
improvised garrison had kept the besiegers at bay.

The legation was safe, but for the rest it was a melancholy tale which
the minister and his suite returned to hear. The sullen glow in the
heavens, that had served them for torches across the city, came, they
learned, from the burning by the infuriated rabble of the homes of their
compatriots. But worse than the loss of property had been the loss of
life. The hatred of the Japanese, that had lain smouldering for
centuries, had at last found a vent. Shortly after the attack on the
palace by the Chinese troops, the cry was raised against the Japanese,
and a wholesale pillage and massacre of the foreigners began....

The Japanese gone, the progressionist ministers, realizing that they had
failed, fled hastily to such concealment as individual ingenuity
suggested.... One alone remained to die at his post. The account of his
death, given by certain private Korean letters, is a tale of as noble an
act of heroism as was ever performed.

When it became evident that the Japanese would withdraw, and the
progressionist leaders be left to their fate, the latter, perceiving
that if they remained they must inevitably fall into the hands of the
enemy, prepared for flight. To the surprise and horror of all the
others, Hong Yöng Sik calmly informed them that he should stay. The
rest, indeed, had better go, but one, he thought, ought to remain, to
show the world that the progressionists were not rebels nor ashamed of
the principles they had professed, and he would be that one. The others,
aghast at his resolve, tried their utmost to dissuade him, but all to no
purpose. Each in turn then offered to stay in his place, but he would
not hear of it. It was more fitting, he replied, that he should remain,
because one of the oldest (he was just thirty years of age); and
forthwith, to signify that his resolve was unalterable, he drew off his
long court boots. Finding it impossible to shake his determination, and
fearing lest, if they delayed longer, they might not escape themselves,
they reluctantly left him and fled. There in the palace, awaiting his
certain doom, the Chinese soldiers found him, a few minutes after. They
seized him and carried him to the Chinese camp, where, with some show of
formality, he was publicly executed. Thus died a brave and loyal soul,
true with his life to the principles he had publicly professed, and
which he deemed it cowardly and wicked to abandon....

Meanwhile, the Japanese lay imprisoned within their legation buildings,
closely besieged by the Koreans. Toward the middle of the day, on the
seventh, they discovered that their provisions were nearly exhausted.
Only the soldiers, therefore, were allowed rice, the rest getting for
their portion the water in which the rice had previously been boiled.
There were now in the compound one hundred and forty soldiers, thirty
servants attached to the legation, about seventy merchants and artisans,
besides many other Japanese residents from the city, who had sought
refuge in the buildings. It was utterly impossible to procure more
provisions. Starvation stared the prisoners in the face, even if they
should contrive to hold out against the assaults of the Koreans. Reports
now reached them that all the gates of Söul had been closed, and that
preparations were everywhere in progress for a general attack. It was
also rumored that this would take place at dusk, and that under cover of
the darkness the legation would be fired by the foe.

Thereupon, Takezoye held a council of war, at which it was decided that
the legation’s only hope, desperate as it was deemed, lay in forcing a
passage through the western gate of the city, and retreating as best
they might to Chemulpo. Accordingly, at the close of the conference the
order was given to withdraw from Söul. It was now discovered that the
messenger to whom the letters were entrusted had been afraid to leave
the legation. Doomed indeed seemed the ill-starred Korean attempt at a
postal system to bring mishap upon everything connected with it, both
big and little, new and old.

Takezoye then addressed the Japanese gathered in the court-yard. He told
them that his guards had been obliged, in defense of the king on the
preceding day, to fire upon the Chinese soldiers, who had broken into
the palace and opened fire upon the royal apartments; that the Korean
troops and people had now combined against the Japanese; that the Korean
government was apparently powerless to protect them; that the legation
was blockaded; that it was impossible longer to carry on the ministerial
functions; and that he had resolved to retire upon Chemulpo, there to
await instructions from Japan. All the confidential dispatches and other
private documents belonging to the legation were then burned.

It was now half past two in the afternoon. The crowd without was
steadily growing larger and larger, and closing in slowly but surely
about the devoted compound. Suddenly, to its amazement, the outer wooden
gates, so stoutly defended a few minutes before, swung inward; there was
a moment’s hush of expectation, and the Japanese column, grim with
determination, defiled in marching order into the street. It was a sight
to stir the most sluggish soul. Instinctively the Koreans fell back,
awed as they read the desperate resolve in the faces of the men; and the
column kept silently, surely, moving on. First came two detachments,
forming the van; then the minister, his suite, the women and children,
followed, placed in the centre and guarded on either hand by rows of
soldiers. Next marched the secretaries and the subordinate officials of
the legation, all armed, and with them the merchants and artisans,
carrying the wounded and the ammunition. Two more detachments brought up
the rear. Debouching into the main road, the body struck out for the
western gate. The Koreans, who crowded the side-streets, the
court-yards, and even the roofs of the houses, had by this time
recovered from their first daze, and began to attack the column on all
sides, firing and throwing stones. So poor was their aim, however, and
so unused were they to the business, that neither bullets nor stones did
the Japanese much harm. The vanguard, lying down in the road, fired at
the assailants and drove them back, and the march proceeded. Nothing
could stop the advance of the van, and the rear-guard as ably covered
the rear. Slowly but surely the column pushed on.

It had thus got half-way across the city, when it encountered a more
formidable obstruction. Opposite the old palace, where a broad avenue
from the palace gates entered the road it was following, a detachment of
the left division of the Korean army had been drawn up, to prevent, if
possible, all escape. The spot was well chosen. On one side lay the army
barracks of the left division, a safe retreat in case of failure, while
in front stretched the broad, open space of the avenue, ending in the
highway along which the Japanese were obliged to pass. To make the most
of this position a field-piece had been brought out and trained on the
cross-road, and deployed beside it the Koreans posted themselves, and
waited for the coming column. As the foreigners came into view, marching
across the end of the avenue, the Koreans opened fire upon them both
with the field-piece and with small arms. The effect should have been
frightful. As a matter of fact it was _nil_, owing to the same cause as
before, the bullets passing some twenty feet over the heads of the
Japanese. Not a single man was killed, and only a few were slightly
wounded. The rear-guard, prone in the street or under cover of the
little gutter-moats, a peculiar feature of all Korean city streets,
calmly took accurate aim, and eventually forced this body of the enemy
back into their barracks. Still harassed at every step by other troops
and by the populace, the column, advancing steadily in spite of them, at
last gained the west gate. It was shut, bolted, and guarded by Korean
soldiers. A sudden onset of the vanguard put these to flight. Some of
the soldiers, armed with axes, then severed the bars, demolished the
heavy wooden doors, and the column passed through. Keeping up a fire on
the foe, who still pursued, the Japanese then made for the principal
ferry of the river Han, at a place called Marpo, one of the river
suburbs of the city. As they turned there to look back toward Söul, they
saw smoke rising from the direction of the legation, and knew from this
that the buildings had already been fired. With the rear-guard set to
protect the important points, they proceeded to cross the stream.
Seizing this opportunity, a parting attack was now made by a
conglomerate collection of Korean troops and tramps, who had pursued
them from the city. Hovering on their flanks, these fired at the ferry
boats as they passed over; but the Japanese rear-guard shot at and
killed some of them, and so succeeded in keeping the others at bay. By
about half past five in the afternoon the Japanese had completed the
crossing. After this no further serious opposition was made to their
retreat, and, following the ordinary road and marching the whole night,
they reached the hill above Chemulpo, and looked down upon the broad
expanse of the Yellow Sea at seven o’clock on the morning of the eighth.

The long, hard fight was over; an end had come at last. They saw it in
the sea stretched out at their feet, just awaking from its lethargy at
the touch of the morning light. To them its gently heaving bosom spoke
of their own return to life. No crazy fishing boat now stood between
them and theirs. One of their own men-of-war lay at anchor in the
offing. There she rode, in all her stately beauty, the smoke curling
faintly upward from her funnel, waiting to bear them across the water to
the arms of those who held them dear. And the sparkling shimmer, as the
rays of the rising sun tinged the Yellow Sea with gold in one long
pathway eastward, seemed Japan’s own welcome sent to greet them, a
proud, fond smile from home.




                               CHAPTER VI
                        THE SOUL OF THE FAR EAST


Back in Japan in the early spring of 1884, Percival stayed there until
midsummer, when he turned his face homeward and westward, for he had
crossed the Pacific three times and preferred to go home the other way.
Touching at Shanghai and Hong Kong he stopped off at Singapore to make a
detour to Java, which delayed him so much that he saw only the southern
part of India. At Bombay he stayed with Charles Lowell, a cousin and
class-mate, in charge of the branch there of the Comptoir d’Escompte of
Paris; thence his route led through the Red Sea and Alexandria to
Venice, where to his annoyance he was quarantined; not, as he
sarcastically remarks, because he came from an infected country, but on
account of cholera in the city itself. Finally he went home by way of
Paris and London.

At this time he had clearly decided to write his book on Korea; for in
his letters, and in memoranda in his letter book, are found many pages
that appear afterwards therein. But he certainly had not lost his
interest in mathematics or physics, for any casual observation would
quickly bring it out. From the upper end of the Red Sea he sees a cloud
casting a shadow on the desert toward Sinai, and proceeds to show how by
the angle of elevation of the cloud, the angle of the sun, and the
distance to the place where the shadow falls one can compute the height
of the cloud. He looks at the reflection of the moon along the water and
points out why, when there is a ripple on the surface, the track of
light does not run directly toward the moon but to windward of it. All
this was a matter of general intellectual alertness in a mind familiar
with the subject, but there is as yet no indication that he had any
intention of turning his attention to scientific pursuits. On the
contrary, two letters written on this journey appear to show that he
regarded literature, in a broad sense, as the field he proposed to
enter, and with this his publications for several years to come accord.

In a letter from Bombay to Frederic J. Stimson,—a classmate who had
already won his spurs by his pen, and was destined to go far,—he begins
by speaking of his friend’s writings, then of the subject in general,
and finally turns to himself and says: “Somebody wrote me the other day
apropos of what I may or may not write, that facts not reflections were
the thing. Facts not reflections indeed. Why that is what most pleases
mankind from the philosopher to the fair; one’s own reflections on or
from things. Are we to forego the splendor of the French salon which
returns us beauty from a score of different points of view from its
mirrors more brilliant than their golden settings. The fact gives us but
a flat image. It is our reflections upon it that make it a solid truth.
For every truth is many-sided. It has many aspects. We know now what was
long unknown, that true seeing is done with the mind from the
comparatively meagre material supplied by the eye....

“I believe that all writing should be a collection of the precious
stones of truth which is beauty. Only the arrangement differs with the
character of the book. You string them into a necklace for the world at
large. You pigeon-hole them into drawers for the scientist. In the
necklace you have the calling of your thought; _i.e._, the expressing of
it and the arrangement of the thoughts among themselves. I wonder how
many men are fortunate enough to have them come as they are wanted. A
question by the bye nearly incapable of solution because what seems good
to one man, does not begin to satisfy the next.”

A month later he writes to his mother from Paris on October 7th: “As for
me, I wish I could believe a little more in myself. It is at all times
the one thing needful. As it is I often get discouraged. You will—said
Bigelow the other day to me in Japan. There will be times when you will
feel like tearing the whole thing up and lighting your pipe with the
wreck. Don’t you do it. Put it away and take it out again at a less
destructive moment.” Then, speaking of what his mother had written him,
he says: “But I shall most certainly act upon your excellent advice and
what is more you shall have the exquisite ennui of reading it before it
goes to print and then you know we can have corrections and improvements
by the family.”

Reaching Boston in the autumn of 1884, he made it his headquarters for
the next four years. The period was far from an idle one; for, apart
from business matters that engaged his attention, he was actively at
work on two books: First, the “Chosön,” that study already described of
Korea and the account of his own sojourn there. The preface to this is
dated November 1885, and the publication was early in the following
year. The second book,—smaller in size and type, and without
illustrations,—is the most celebrated of his writings on the Orient. Its
title, “The Soul of the Far East,” denotes aptly its object in the mind
of the author, for it is an attempt to portray what appeared to him the
essential and characteristic difference between the civilizations of
Eastern Asia and Western Europe. From an early time in his stay in Japan
he had been impressed by what he called the impersonality of the people,
the comparative absence, both in aspiration and in conduct, of
diversified individual self-expression among them. The more he thought
about it the stronger this impression became; and this book is a study
of the subject in its various manifestations.

First comes a general discussion of the meaning and essence of
individuality, with the deduction that the Japanese suffer from arrested
development; that they have always copied but not assimilated; added but
not incorporated the additions into their own civilization, like a tree
into which have been grafted great branches while the trunk remains
unchanged. “The traits that distinguished these peoples in the past have
been gradually extinguishing them ever since. Of these traits,
stagnating influences upon their career, perhaps the most important is
the great quality of impersonality”; and later he adds, “Upon this
quality as a foundation rests the Far Oriental character.”

He then proceeds to demonstrate, or illustrate, his thesis from many
aspects of Japanese life, beginning with the family. He points out that
no one has a personal birthday or even age of his own, two days in the
year being treated as universal birthdays, one for girls and the other
for boys, the latter, in May, being the occasion when hollow paper fish
are flown from poles over every house where a boy has been born during
the preceding year. Everyone, moreover, is credited with a year’s
advance in age on New Year’s Day quite regardless of the actual date of
his birth. If a youth “belongs to the middle class, as soon as his
schooling” in the elements of the Classics “is over he is set to learn
his father’s trade. To undertake to learn any trade but his father’s
would strike the family as simply preposterous.” But to whatever class
he may belong he is taught the duty of absolute subordination to the
head of the family, for the family is the basis of social life in the
Far East. Marriage, with us a peculiarly personal matter, is in the East
a thing in which the young people have no say whatever; it is a business
transaction conducted by the father through marriage brokers. A daughter
becoming on marriage a part of her husband’s family ceases to be a
member of her own, and her descendants are no benefit to it, unless,
perchance, having no brothers, one of her sons is adopted by her father.
Thus it is that when a child is born the general joy “depends somewhat
upon the sex. If the baby chances to be a boy, everybody is immensely
pleased; if a girl there is considerably less effusion shown. In the
latter case the more impulsive relatives are unmistakably sorry; the
more philosophic evidently hope for better luck next time. Both kinds
make very pretty speeches, which not even the speakers believe, for in
the babe lottery the family is considered to have drawn a blank. A
delight so engendered proves how little of the personal, even in
prospective, attaches to its object.”

In the fourth chapter he takes up the question of language, bringing out
his point with special effect, showing the absence of personal pronouns,
and indeed of everything that indicates an expression of individuality
or even of sex, replacing them by honorifics which occur in the most
surprising way. But the matter of language, though highly significant,
is somewhat technical, and his discussion can be left to those who care
to follow it in his book.

He turns next to nature and to art, pointing out how genuine, how
universal, and at the same time how little individual, how impersonal,
is the Japanese love of those things. Of them he says “that nature, not
man, is their _beau idéal_, the source to them of inspiration, is
evident again in looking at their art.” Incidentally, the account of the
succession of flower festivals throughout the year is a beautiful piece
of descriptive writing, glowing with the color it portrays and the
delight of the throngs of visitors.

On the subject of religion he has much to say. Shintoism, though
generally held by the people, and causing great numbers of them to go as
pilgrims to the sacred places on mountain tops, he regards as not really
a religion. That is the reason it is not inconsistent with Buddhism. “It
is not simply that the two contrive to live peaceably together; they are
actually both of them implicitly believed by the same individual.
Millions of Japanese are good Buddhists and good Shintoists at the same
time. That such a combination should be possible is due to the essential
difference in the character of the two beliefs. The one is extrinsic,
the other intrinsic, in its relations to the human soul. Shintoism tells
a man but little about himself and his hereafter; Buddhism, little but
about himself and what he may become. In examining Far Eastern religion,
therefore, for personality, or the reverse, we may dismiss Shintoism as
having no particular bearing upon the subject.” Turning to the other
system he says: “At first sight Buddhism is much more like Christianity
than those of us who stay at home and speculate upon it commonly
appreciate. As a system of philosophy it sounds exceedingly foreign, but
it looks unexpectedly familiar as a faith.” After dwelling upon the
resemblances in the popular attitude, he continues: “But behind all this
is the religion of the few,—of those to whom sensuous forms cannot
suffice to represent super-sensuous cravings; whose god is something
more than an anthropomorphic creation; to whom worship means not the
cramping of the body, but the expansion of the soul.”... “In relation to
one’s neighbor the two beliefs are kin, but as regards one’s self, as
far apart as the West is from the East. For here, at this idea of self,
we are suddenly aware of standing on the brink of a fathomless abyss,
gazing giddily down into that great gulf which divides Buddhism from
Christianity. We cannot see the bottom. It is a separation more profound
than death; it seems to necessitate annihilation. To cross it we must
bury in its depths all we know as ourselves.

“Christianity is a personal religion; Buddhism, an impersonal one. In
this fundamental difference lies the worldwide opposition of the two
beliefs. Christianity tells us to purify ourselves that we may enjoy
countless aeons of that bettered self hereafter; Buddhism would have us
purify ourselves that we may lose all sense of self for evermore.”

At the end of this chapter he sums up his demonstration thus: “We have
seen, then, how in trying to understand these peoples we are brought
face to face with impersonality in each of those three expressions of
the human soul, speech, thought, yearning. We have looked at them first
from a social standpoint. We have seen how singularly little regard is
paid the individual from his birth to his death. How he lives his life
long the slave of patriarchal customs of so puerile a tendency as to be
practically impossible to a people really grown up. How he practises a
wholesale system of adoption sufficient of itself to destroy any
surviving regard for the ego his other relations might have left. How in
his daily life he gives the minimum of thought to the bettering himself
in any worldly sense, and the maximum of polite consideration to his
neighbor. How, in short, he acts toward himself as much as possible as
if he were another, and to that other as if he were himself.

“Then, not content with standing stranger-like upon the threshold, we
have sought to see the soul of their civilization in its intrinsic
manifestations. We have pushed our inquiry, as it were, one step nearer
its home. And the same trait that was apparent sociologically has been
exposed in this our antipodal phase of psychical research. We have seen
how impersonal is his language, the principal medium of communication
between one soul and another; how impersonal are the communings of his
soul with itself. How the man turns to nature instead of to his
fellowman in silent sympathy. And how, when he speculates upon his
coming castles in the air, his most roseate desire is to be but an
indistinguishable particle of the sunset clouds and vanish invisible as
they into the starry stillness of all-embracing space.

“Now what does this strange impersonality betoken? Why are these peoples
so different from us in this most fundamental of considerations to any
people, the consideration of themselves? The answer leads to some
interesting conclusions.”

The final chapter is entitled “Imagination,” for he regards this as the
source of all progress, and the far orientals as particularly
unimaginative. Their art he ascribes to appreciation rather than
originality. They are, he declares, less advanced than the occidentals,
their rate of progress is less rapid and the individuals are more alike;
and he concludes that unless their newly imported ideas really take root
they will vanish “off the face of the earth and leave our planet the
eventual possession of the dwellers where the day declines.”

One cannot deny that he made a strong case for the impersonality of the
Japanese; and if it be thought that his conclusions therefrom were
unfriendly it must be remembered that he had a deep admiration and
affection for that people, wishing them well with all his heart.

Without attempting to survey the reviews and criticisms of the book,
which was translated into many languages, it may be interesting to
recall the comments of three Europeans of very diverse qualities and
experiences. Dr. Pierre Janet, the great French neurologist, said to a
friend of the author that as a study of Japanese mentality it seemed to
him to show more insight than any other he had ever read on the subject.

The second commentator is Lafcadio Hearn, a very different type of
person, given to enthusiasm. He had not yet been to Japan, and “The Soul
of the Far East” had much to do with his going there. In his book
“Concerning Lafcadio Hearn” George M. Gould says:

  “Perhaps I should not have succeeded in getting Hearn to attempt Japan
  had it not been for a little book that fell into his hands during the
  stay with me. Beyond question, Mr. Lowell’s volume had a profound
  influence in turning his attention to Japan and greatly aided me in my
  insistent urging him to go there. In sending the book Hearn wrote me
  this letter:

  “Gooley!—I have found a marvellous book,—a book of books!—a colossal,
  splendid, godlike book. You must read every line of it. For heaven’s
  sake don’t skip a word of it. The book is called “The Soul of the Far
  East,” but its title is smaller than its imprint.

                                                              Hearneyboy

  “P.S. Let something else go to H—, and read this book instead. May God
  eternally bless and infinitely personalize the man who wrote this
  book! Please don’t skip one solitary line of it, and don’t delay
  reading it,—because something, much! is going to go out of this book
  into your heart and life and stay there! I have just finished this
  book and feel like John in Patmos,—only a d——d sight better. He who
  shall skip one word of this book let his portion be cut off and his
  name blotted out of the Book of Life.”

Hearn had read the book on Korea and was impressed by that also, for in
a letter of 1889, he wrote, after commenting on another work he had been
reading, “How luminous and psychically electric is Lowell’s book
compared with it. And how much nobler a soul must be the dreamer of
Chosön!”[5]

After living in Japan Hearn came to different conclusions about
Percival’s ideas on the impersonality of the Japanese, but he never lost
his admiration for the book or its author. In May, 1891, he writes;

  “Mr. Lowell has, I think, no warmer admirer in the world than myself,
  though I do not agree with his theory in “The Soul of the Far East,”
  and think he has ignored the most essential and astonishing quality of
  the race: its genius of eclecticism.”[6]

And again,

  “I am not vain enough to think I can ever write anything so beautiful
  as his “Chosön” or “Soul of the Far East,” and will certainly make a
  poor showing beside his precise, fine, perfectly worded work.”[7]

And, finally, as late as 1902 he speaks of it as “incomparably the
greatest of all books on Japan, and the deepest.”[8]

The third European critic to be quoted is Dr. Clay Macauley, a Unitarian
missionary to Japan, who had been a friend of Percival’s there, and
after his death at Flagstaff in 1916 was still at work among the
Japanese. On January 24, 1917, he read before the Asiatic Society of
Japan a Memorial to him, in which he gave an estimate of “The Soul of
the Far East”:

  “The year after the publication of “Cho-son,” the book which has
  associated Lowell most closely with a critical and interpretative
  study of the peoples and institutions of this part of the world,
  appeared his much-famed “Soul of the Far East.” I have no time for an
  extended critique of this marvellous ethnic essay. “Marvellous” I name
  it, not only because of the startling message it bears and the
  exquisitely fascinating speech by which the message is borne, but also
  because of the revelation it gives of the distinctive mental measure
  and the characteristic personality of the author himself ... the book
  is really a marvellous psychical study. However, in reading it today,
  the critical reader should, all along, keep in mind the time and
  conditions under which Lowell wrote. His judgment of “The Soul of the
  Far East” was made fully a generation ago. Time has brought much
  change to all Oriental countries since then, especially to this “Land
  of the Rising Sun.”

He then refers to the author’s conviction that owing to their
impersonality the Oriental people, if unchanged and unless their newly
imported ideas take root, would disappear before the advancing nations
of the West, and proceeds:

  “Now, notice Lowell’s “ifs” and “unless.” He had passed his judgment;
  but he saw a possible transformation. And I know that he hailed the
  incoming into the East of the motive forces of the West as forerunner
  of a possible ascendancy here of the genius of the world’s advancing
  civilization, prophetic of that New East into which, now, the Far East
  is becoming wonderously changed.”

Japan certainly is not in a process of disappearing before the advancing
nations of the West; but it may be that this is not because her people
have radically changed their nature. The arts of the West, civil and
military, they have thoroughly acquired; but Percival Lowell may have
been right in his diagnosis and wrong in his forecast. His estimate of
their temperament may have been correct, and the conclusion therefrom of
their destiny erroneous. The strange identity with which all Japanese
explain the recent international events is not inconsistent with his
theory of impersonality, and it may be that from a national standpoint
this is less a source of weakness than of strength.




                              CHAPTER VII
                         SECOND VISIT TO JAPAN


Having got “The Soul of the Far East” off his hands, and into those of
the public, in 1888, he sailed in December for Japan, arriving on
January the eighth. As usual he took a house in Tokyo and on January 23
he writes to his mother about it. “My garden is a miniature range of
hills on one side, a dry pond on the other. One plum tree is blooming
now, another comes along shortly, and a cherry tree will peep into my
bedroom window all a-blush toward the beginning of April. A palm tree
exists with every appearance of comfort in front of the drawing room, a
foreground for the hills.

“The fictitious employment by the Japanese has developed into a real one
most amusingly—You know by the existing law a foreigner is not allowed
to live outside of the foreign reservation unless in the service of some
native body, governmental or private. Now Chamberlain got a Mr. Masujima
to arrange matters. The plan that occurred to him, Masujima, was to
employ me to lecture before the School of Languages of which he,
Masujima, is President. It was thought better to make the thing in part
real, a suggestion I liked, and the upshot of it is that I am booked to
deliver a lecture a week until I see fit to change. Chamberlain and
Masujima cooked up between them the idea of translating my initial
performance and then inserting it in a reader of lectures, sermons and
such in the colloquiae which Chamberlain is preparing—Subject—A homily
to the students to become superior Japanese rather than inferior
Europeans. Curious if you will in view of the fact that Masujima himself
is madly in love with foreigners and as C. says is a sort of universal
solvent for their quandaries.”

January 1889 proved a peculiarly fortunate time to arrive, for most
interesting events were about to take place, as he soon wrote to his old
college chum, Harcourt Amory, on February 21:

“Things have been happening since I arrived. Indeed I could hardly have
lit upon a more eventful month—from doings of the Son of Heaven to those
of Mother Earth—the transmigration from the old to the new palace, the
ceremony of the promulgation of the Constitution, and the earthquake,
and the assassination of Mori—and his burial the most huge affair of
years. How he was murdered on the morning of the great national event
just as he was setting out for the palace by a fanatic in the
ante-chamber of his own house because two years ago he trod on the mats
at Ise with his boots and poked the curtains aside with his cane—you
have probably already heard—For the affair was too dramatic to have
escaped European and American newspapers. The to us significant part of
the story is the quasi sublatent approval of large numbers of Japanese.
The whole procedure of the assassin commends itself in method to their
ideas of the way to do it. The long cherished plan, the visit to the
temples of Ise for corroboration of facts, the selection of the day, the
coolness shown beforehand, the facing of death in return, the very blows
à la hari-kiri etc., all tout-a-fait comme il faut. How he went to a
joroya (house of prostitution) the night before, saying that he wished
to have experienced as many phases of life as possible before leaving
it, how the official who received him at Mori’s house (he introduced
himself by the story that he had come to warn Mori of a plot to
assassinate him) could recall no signs of nervousness in him, except
that he lifted his teacup to drink once or twice after he had emptied
it.

“The whole affair appeals to their imaginations, showing still a pretty
state of society. They also admire the beautiful way the guard killed
him, decapitating him in the good old-fashioned way just leaving his
head hanging to his neck by a strip—Pleasing details.”

The story of the murder of Mori, and of the public festivities that were
going on at the time, he told under the title of “The Fate of a Japanese
Reformer” in the _Atlantic Monthly_ for November 1890. It is perhaps the
best of his descriptive writings, for the tragedy and its accessories
are full of striking contrasts which he brought out with great effect.
After a prelude on the danger of attempting changes too rapidly, he
gives a brief account of the life of Mori Arinori; how in his youth he
was selected to study abroad, how he did so in America, and became
enamored of occidental ways, returning in time for the revolution that
restored the Mikado. He threw himself into the new movement, rose in
office, and, as he did so, strove to carry out his ideas. He was the
first to propose disarming the _samurai_, which against bitter
opposition was accomplished. As Minister of Education he excluded
religion from all national instruction. He even suggested that the
native language should be superseded by a modified English, the American
people to adopt the changes also; but the plan obtained no support on
either side of the Pacific.

The Japanese reformers felt that like almost all Western nations Japan
should have a written constitution, and they set the date for its
promulgation at February 11th, 1889. This Percival thought a mistake
since it was the festival of Jimmu Tenno, the mythic founder of the
imperial house. Nevertheless, the reformers, who had virtual control of
the government, determined that the two celebrations should take place
on the same day; and he describes the gorgeous decoration of the city as
he saw it, the functions attending the grant of the constitution, and
processions of comic chariots in honor of Jimmu Tenno. To a foreigner
the strange mixture of native and partially imitated European costumes
was irresistibly funny; but the populace enjoyed themselves. “The rough
element,” he says, “so inevitable elsewhere was conspicuously absent.
There is this great gain among a relatively less differentiated people.
If you miss with regret the higher brains, you miss with pleasure the
lower brutes. _Bons enfants_ the Japanese are to a man. They gather
delight as men have learned to extract sugar, from almost anything....
As the twilight settled over the city, a horrible rumor began to creep
through the streets. During the day the thing would seem to have shrunk
before the mirth of the masses, but under the cover of gloom it spread
like night itself over the town. It passed from mouth to mouth with
something of the shudder with which a ghost might come and go. Viscount
Mori, Minister of State for Education, had been murdered that morning in
his own house....

“What had happened was this:—

“While Viscount Mori was dressing, on the morning of the 11th, for the
court ceremony of the promulgation of the new Constitution, a man,
unknown to the servants, made summons on the big bell hung by custom at
the house entrance, and asked to see the Minister on important business.
He was told the Minister was dressing, and could see no one. The unknown
replied that he must see him about a matter of life and death,—as indeed
it was. The apparent gravity of the object induced the servant to admit
him to an ante-chamber and report the matter. In consequence, the
Minister’s private secretary came down to interview him. The man, who
seemed well behaved, informed the secretary that there was a plot to
take the Minister’s life, and that he had come to warn the Minister of
it. Truly a subtle subterfuge; true to the letter, since the plot was
all his own. More he refused to divulge except to the Minister himself.
While the secretary was trying to learn something more definite, Mori
came down stairs, and entered the room. The unknown approached to speak
to him; then, suddenly drawing a knife from his girdle, sprang at him,
and crying ‘This for desecrating the shrines of Ise!’ stabbed him twice
in the stomach. Mori, taken by surprise, grappled with him, when one of
his body guards, hearing the noise, rushed in, and with one blow of his
sword almost completely severed the man’s head from his body.

“Meanwhile, Mori had fallen to the floor, bleeding fast. The secretary,
with the help of the guard, raised him, carried him to his room, and
despatched a messenger for the court surgeon.

“The clothes of the unknown were then searched for some clue to the
mystery; for neither Mori nor any of his household had ever seen him
before. The search proved more than successful. A paper was found on his
person, setting forth in a most circumstantial manner the whole history
of his crime, from its inception to its execution, or his own. However
reticent he seemed before the deed, he evidently meant nothing should be
hid after it, whether he succeeded or not. The paper explained the
reason.

“Because, it read, of the act of sacrilege committed by Mori Arinori,
who, on a visit to the shrines of Ise, two years before, had desecrated
the temple by pushing its curtain back with his cane, and had defiled
its floor by treading upon it with his boots, he, Nishino Buntaro, had
resolved to kill Mori, and avenge the insult offered to the gods and to
the Emperor, whose ancestors they were. To wipe the stain from the
national faith and honor, he was ready to lose his life, if necessary.
He left this paper as a memorial of his intent.”

In the meantime the messenger sent for the court surgeon failed to find
him, for he was at the palace. The same was true of the next in rank,
and when at last a surgeon was found Mori had lost so much blood that in
the night of the following day he died.

Both by his opinions and his tactless conduct as a minister Mori had
made himself unpopular and rumors that his life was in danger had been
current for two or three days. “If Mori was thus a very definite sort of
person, Nishino was quite as definite in his own way.” At the time of
his crime he held a post in the Home Department, where he brooded over
the insult to the gods. “He seems to have heard of it accidentally, but
it made so much impression upon him that he journeyed to Ise to find out
the truth of the tale. He was convinced, and forthwith laid his plans
with the singleness of zeal of a fanatic,” as appears from his
affectionate farewell letters to his father and his younger brother.

“But the strangest and most significant part of the affair was the
attitude of the Japanese public toward it. The first excitement of the
news had not passed before it became evident that their sympathy was not
with the murdered man, but with his murderer.... Nishino was an
unknown.... Yet the sentiment was unmistakable. The details of the
murder were scarcely common property before the press proceeded to
eulogize the assassin. To praise the act was a little too barefaced, not
to say legally dangerous.... But to praise the man became a journalistic
epidemic.... Nishino, they said, had contrived and executed his plan
with all the old time _samurai_ bravery. He had done it as a _samurai_
should have done it, and he had died as a _samurai_ should have died....
The summary action of the guard in cutting the murderer down was
severely censured. As if the guard had not been appointed to this very
end!... The papers demanded the guard’s arrest and trial.... Comment of
this kind was not confined to the press. Strange as it may appear, the
newspapers said what everybody thought.... There was no doubt about it.
Beneath the surface of decorous disapproval ran an undercurrent of
admiration and sympathy, in spots but ill hid. People talked in the same
strain as the journalists wrote. Some did more than talk. The geisha, or
professional singing girls of Tokyo, made of Nishino and his heroism a
veritable cult.... His grave in the suburbs they kept wreathed with
flowers. To it they made periodic pilgrimages, and, bowing there to the
gods, prayed that a little of the hero’s spirit might descend on them.
The practice was not a specialty of professionals. Persons of all ages
and both sexes visited the spot in shoals, for similar purposes. It
became a mecca for a month. The thing sounds incredible, but it was a
fact. Such honor had been paid nobody for years.”

This in abstract is Percival’s account of a terrible national tragedy,
and its amazing treatment by the public at large.

Before he had been long in Japan the old love of travel into regions
unknown to foreigners came back. He had already visited some of the less
frequented parts of the interior, and now scanning, one evening, the map
of the country his eye was caught by the pose of a province that stood
out in graphic mystery, as he said, from the western coast. It made a
striking figure with its deep-bosomed bays and its bold headlands. Its
name was Noto; and the more he looked the more he longed, until the
desire simply carried him off his feet. Nobody seemed to know much about
it, for scarcely a foreigner had been there; and, in fact, he set his
heart on going to Noto just because it was not known. That is his own
account of the motive for the journey he made early in May, 1889; which
turned out somewhat of a disappointment, for the place was not, either
in its physical features or the customs of its people, very different
from the rest of Japan; but for him proved adventurous and highly
interesting. Under the title of “Noto” he gave an account of it,—as
usual after his return home in the following spring,—first by a series
of articles in the _Atlantic_, and then as a book published in 1891. It
is a well-told tale of a journey, quite exciting, where he and his
porters, in seeking to scale a mountain pass, found their way lay along
precipices where the path had crumbled into the gorge below. The
descriptions of people and scenery are vigorous and terse; but the book
is not a philosophic study like those on Korea and on Japanese
psychology. Yet it is notable in showing his versatility, as is also the
fact that he gave the Φ Β Κ poem at Harvard in June of that year.

Hurrying home to deliver that poem, shortly after his return from Noto,
he found himself busy for a year and a half, writing, attending to his
own affairs, and to business, for he was part of the time, as Treasurer,
the manager of the Lowell Bleachery. Meanwhile his hours of leisure were
filled with a new and absorbing avocation, that of polo.

As a boy at Brookline, Patrick Burns, the coachman, trained at
Newcastle, had taught him to ride bareback with a halter for a
bridle—although he had never really cared for riding, just as in college
he had run races without taking much interest in athletics. But on
August 9, 1887, we find him writing that he has bought a polo pony, and
that “Sam Warren, Fred Stimson, et al. have just started a polo club at
Dedham, and have also in contemplation the erection of an inn there.” He
adds that he is in both schemes; and in fact the plan for an inn
developed into a clubhouse, where he lived in summer for some years when
about Boston. During the remainder of the first season the players
knocked the ball about—and rarely with a full team of four in a
side—tried to learn the game on a little field belonging to George
Nickerson, another member of the club. But the next year the number
increased, and Percival with his great quickness and furious energy soon
forged ahead, leading the list of home handicaps in the club with a
rating of ten, and becoming the first captain of the team.

By the autumn of 1888 they had become expert enough to play a match with
the Myopia club on its grounds at Hamilton, but with unfortunate
results. At that time it was the habit to open the game by having the
ball thrown into the middle of the field, and at a signal the leading
player from each side charged from his goal posts, each trying to reach
the ball first. Percival had a very fast pony, so had George von L.
Meyer on the other side, and by some misunderstanding about the rules of
turning there was a collision. In an instant both men and both horses
were flat on the field. Percival was the most hurt, and although he
mounted his horse and tried to play, he was too much stunned to be
effective, and had to withdraw from the game.

In the following years he played as captain other match games with
various teams; and, in fact, the Dedham Polo Club, which he came to
regard as his home, was certainly his chief resource for recreation and
diversion in this country until he built his Observatory in Arizona. Yet
it by no means absorbed his attention, for with all the vigor he threw
into anything he undertook he could maintain an intense interest in
several things at the same time, besides being always ready for new
ones, not least in the form of travel. So it happened that at the end of
January, 1890, he sailed again for Europe, and with Ralph Curtis, a
friend from boyhood and a college classmate, visited Spain—not in this
case to study the people or the land, although he observed what he saw
with care, but for the pleasure and experience. Like all good travellers
he went to Seville for Holy Week and the festivities following; but,
being sensitive, the bullfight was a thing to be seen rather than
enjoyed. He had heard people speak also of the cathedral of Burgos as
marvellous, in fact as the finest specimen in the world; so, at some
inconvenience, he went there on his way to France, and on seeing it
remarked that the praise bestowed upon it was due less to its merits
than to its inaccessibility. Later he noticed that having taken the
trouble to go to Burgos he never heard anyone speak of it again. So much
for people’s estimates of things someone else has not seen.

On his way home he passed through London and enjoyed the hospitality he
always found there.




                              CHAPTER VIII
                     JAPAN AGAIN—THE SHINTO TRANCES


The trip to Spain was merely an interlude; for, above all, at this time
he felt the attraction of Japan. Returning from Europe in June he spent
the summer in Dedham; but when winter came he started again for the Far
East, this time by way of Europe, where he picked up Ralph Curtis; and
then by the Red Sea to India and Burma, reaching Tokyo about the first
of April, 1891. By far the most interesting part of this visit to Japan
arose from a journey which he took with George Agassiz in July and
August, into the interior of the Island. Agassiz became a most devoted
friend, who followed his studies here, and later in Flagstaff, taking
part in his observations and writing a memorial after his death. Their
object was travel through a part of the mountainous region, ending at
Ontake, a high extinct volcano, one of Japan’s most sacred peaks. But
the holiness of the spot, or the religious pilgrimages thereto, were not
the motive of the visit; nor did they expect to see anything of that
nature with which they were not already familiar.

Leaving Tokyo by train on July 24, they soon reached a point where they
got off and took jinrikishas to descend later to their own feet on a
path that came “out every now and then over a view at spots where
Agassiz said one had to be careful not to step over into the view one’s
self.” For the next three days the lodging was not too comfortable, the
heat terrific and the footpath going over a steep mountain pass.
However, the weather improved; and without serious misadventure they
were, on August 6, ascending Ontake, and not far from the top, when they
saw three young men, clad as pilgrims, begin a devotional ceremony. One
of them seated on a bench before a shrine, went through what looked like
contortions accompanied by a chant, while another, at whom they were
directed, sat bowed on the opposite bench motionless until, beginning to
twitch, he broke into a paroxysm and ended by becoming stiff though
still quivering. Then the first leaned forward, and bowing down, asked
the name of the god that possessed his companion. The other in a strange
voice answered “I am Hakkai.” Whereat the first asked, as of an oracle,
questions that were answered; and after the god had finished speaking,
said a prayer and woke the other from his trance. But this was not the
end, for the same thing was repeated, the three changing places by
rotation until each of them had been petitioner and entranced. On
several more occasions the ceremony was enacted during the next
thirty-six hours, the young men fasting all that time. The whole scene
is more fully described in the opening chapter of Percival’s “Occult
Japan.”

With his temperament and literary ambition he thought at once of writing
about this extraordinary sight, which he connected as a phenomenon with
the fox possession he had already encountered on a lower plane. He
suggested the title “Ontake, a Pilgrimage,” but he soon saw the whole
matter on a larger scale. The cult seemed to be unknown beyond its
votaries, nothing did he find written upon it, the few foreigners who
had scaled the mountain had missed it altogether, although, as he says,
their guides or porters must have been familiar with it. Dr. Sturgis
Bigelow, who was a student and believer in Buddhism, had never heard of
it, which seemed strange, for although a Shinto, not a Buddhist, rite
many people accepted both faiths, and one Buddhist sect practiced
something akin to it. Moreover, its underlying idea of possession by
another spirit appeared to ramify, not only into fox possession, but in
many other directions. On inquiry he found that there was an
establishment of the Ontake cult in Tokyo, and the head of it the
Kwanchō, or primate of that Shinto sect. This man proved very friendly
and gave all the information about its rites, their significance and
underlying philosophy, within his knowledge,—perhaps beyond it,—and
arranged exhibits; all of which Percival carefully recorded in his
notebooks. Every motion made in inducing the trance, every implement
used in the ceremony, had its meaning and its function, which he strove
to learn. Moreover, there were miracles of splashing with boiling water,
walking over hot coals and up ladders with sword blades for rungs;
curing disease; consulting the fox and the raccoon-faced dog, which he
called Japanese table turning; and other less dignified performances
more or less connected with the idea of divine or demonic possession.
Some of these things he was able to witness by séances in his own house,
others by visits to the places where they were performed, often for his
special benefit.

All this took more time than he had expected to spend in Japan, and
delayed his sailing until the autumn was more than half over. Nor was
this enough to complete his researches. In December of the following
year he re-crossed the Pacific, and at Christmas we find him at
Yokohama. Again he hires a house, fits it up in Japanese style but with
occidental furniture; again he was travelling over the land, this time
in search less of scenery than of psychic phenomena and the lore
connected with their celebration. In July he is interviewing a Ryobu
Shinto priest and “eliciting much valuable information.”

For the trances, and the various miracles, a participant must be
prepared by a process of purification, long continued for the former,
always by bathing before the ceremony; and by Percival’s frequent
attendance, and great interest, he attained the repute for a degree of
purity that enabled him to go where others were not admitted. On this
ground he attended what he called the Kwanchō’s Kindergarten, but was
not allowed to bring a friend. The Kwanchō, as the head of the principal
Shinto sect that practised trances, had a class of boys and girls who
went through a preparation therefor by a series of what an unbeliever
might call ecstatic acrobatic feats, lasting a long time before they
were fitted for subjects of divine possession. He visited everything
relating to the mysteries that he could find, procured from the Kwanchō
an introduction that enabled him to see the interior grounds of the
great shrines of Ise, from which even the pilgrims were excluded, and to
see there a building whereof he learned the history and meaning that the
very guardian priests did not understand. At trances he was allowed to
examine the possessed, take their pulse, and even to stick pins into
them to test their sensibility, sometimes in a way that they were far
from not feeling afterwards. In short he was enabled as no one had ever
been before, to make a very thorough examination of the phenomena with
the object of discovering and revealing their significance; for he was
convinced that they were perfectly genuine, without a tinge of fraud,
and allied to the hypnotism then at the height of its vogue. In March,
1893 he gave the first of a series of papers on Esoteric Shintoism
before the Asiatic Society of Japan. These he worked up after his return
to America in the autumn, and published in 1895 with the title “Occult
Japan or the Way of the Gods.”

A casual reader might be misled by occasional cleverness of expression
into thinking the book less serious than it is. Perhaps that accounts in
part for Lafcadio Hearn’s calling it supercilious. Percival himself
says, in the first paragraph of the chapter on Miracles: “It is quite
possible to see the comic side of things without losing sight of their
serious aspect. In fact, not to see both sides is to get but a
superficial view of life, missing its substance. So much for the people.
As for the priests, it is only necessary to say that few are more
essentially sincere and lovable than the Shintō ones; and few religions
in a sense more true. With this preface for life-preserver I plunge
boldly into the miracles.” In fact, expressions that appear less serious
than the subject merits are few, and the descriptions, of the trances
for example, are almost strangely appreciative, and for a scientific
study keenly sympathetic and beautiful.

The book opens with an account of the trances of the three young men on
Mount Ontake, for that sight was the source of all these researches. He
next lays a foundation for the study of the subject by a short history
of the Japanese religions; how Shinto, the old cult, with its myriad
divinities and simple rites, was for a time overshadowed by Buddhism, to
be restored with the power of the Mikado; and how with its revival the
popularity of the trances returned. They had been kept alive by a single
Buddhist sect which had adopted them, but now they are even more widely
practised by two out of the ten Shinto sects, their sacred site being
Ontake. But before taking up the trances he describes the lesser, and
better known, cases of miraculous intervention for protection from
injury and for sanctification; notably, being sprinkled with boiling
water, walking over a bed of hot coals, and up and down a ladder of
sword blades; and he discusses why no injury occurs. The walking over
hot coals, at least, was even performed in his own garden; and, although
he does not say so in the book, he did it himself, without, however,
complete immunity to the soles of his feet.

After telling of what he terms objective, as distinguished from
subjective, miracles, such as bringing down fire from heaven; and saying
something of miraculous healing of disease, he comes to the main subject
of the book, the incarnations or trances. First he speaks of the
preparation for them, washing and fasting which are arduous and long,
the purification of persons and places, and a series of ceremonies
which, he says, tend to promote vacuity of mind. All these things are
absolutely sincere, for he declares that the first view of a trance
dispels any idea of sham. He then describes three typical trances: first
Ryobu, a Shinto-Buddhist sect, where one of the men possessed, on coming
back to himself, was disappointed that he had not spoken English, which
he did not know himself; for to his mind it was not he that spoke but
the god who entered into him. The second example was a Buddhist trance
with the full complement of eight persons filling their several offices
in the ceremony. This description is especially striking and
sympathetic. The third case is of a pure Shinto trance, much the same,
but with the simpler ceremonial of that cult. He describes also the
Kwanchō’s training school, which has already been referred to as the
Kindergarten. He notes the pulse, insensibility, the other physical
conditions and sensations of the possessed, the sex and number of the
gods who enter him, for the exorcist has no power to invoke the spirit
he would prefer, but simply calls for a god, and when one comes inquires
who it is. It may be a god or a goddess, and several of them may come in
succession. The main object of the proceeding being to obtain counsel or
prophecy, the exorcist, and he alone, can ask questions of him, but he
can do so on behalf of anyone else, and often did so for Percival about
his own affairs, although the prophecies appear never to have turned out
right.

A chapter is devoted to pilgrimages and the pilgrim clubs, which
included in the aggregate vast numbers of people, only a minute part of
whom, however, belonged to the trance sects. They subscribed small sums
to be used to send each year a few of their members to the shrine or
sacred mountain with which the club is associated; this feature of the
religious organization being as important from a social as a religious
point of view. Another chapter is given to the Gohei, or sacred cluster
of paper strips, used for all spiritual purposes, and essential in
calling down any god; an emblem which he compares with the crucifix,
while pointing out the difference in their use. This first part of the
book ends with an argument, apparently to one who knows nothing about
the matter conclusive, that the whole subject of these trances is of
Shinto not Buddhist origin; and in this connection he tells of his visit
to the shrines of Ise where a temple was built to the sun-goddess when
she possessed people, as she has long ceased to do at these shrines.

So far the book is scientific; that is, it consists of a description and
analysis of phenomena repeatedly observed and carefully tested. The
second part, which he calls Noumena, is an explanation of them on
general psychological principles, and thus belongs rather to philosophy
than science. It comprises discussions of the essence of self, of the
freedom of the will, of the motive forces of ideas, of individuality, of
dreams, hypnotism and trances. In these matters he was much influenced
by the recently published “Psychology” of William James, which he had
with him, and he draws comparisons with hypnotism, a more prominent
subject then than it is now. Bearing in mind his dominant thought about
the essential quality of the Japanese, it is not unnatural that he
should find in the greater frequency of such phenomena among them than
elsewhere a confirmation of his theory of their comparative lack of
personality.

Perhaps his own estimate of the relative value of the two parts of the
book and that of critics might not agree; but, however that may be, the
second part is penetrating, and the work as a whole a remarkable study
of a subject up to that time practically wholly concealed from the many
observers of Japanese life and customs. It was, in fact, his farewell to
Japan, for, leaving in the fall of 1893, he never again visited that
land. Ten years its people had been his chief intellectual interest, but
perhaps he thought he had exhausted the vein in which he had been at
work, or another interest may have dislodged it. He has left no
statement of why he gave up Japan for astronomy, but probably there is
truth in both of these conjectures.

Talking later to George Agassiz, Percival attributed the change to the
fact that Schiaparelli, who had first observed the fine lines on the
planet Mars which he called “canali,” found that his failing eyesight
prevented his pursuing his observations farther, and that he had
determined to carry them on. That may well have directed his attention
to the particular planet; but the interest in astronomy lay far deeper,
extending back to the little telescope of boyhood on the roof of his
father’s house at Brookline. We have seen that his Commencement Part at
graduation was on the nebular hypothesis, and he never lost his early
love of such things. In July, 1891, he writes to his brother-in-law,
William L. Putnam, about a project for writing on what he calls the
philosophy of the cosmos, with illustrations from celestial mechanics.
That was just before he went to Ontake and there became involved in the
study of trances, “which,” as he says in his next letter to the same,
“adds another to my budget of literary eventualities.” In fact, the
trances occupied most of his time for the next two years, without
banishing the thought of later taking up other things, or effacing the
lure of astronomy, for in 1892 he took with him to Japan a six-inch
telescope, no small encumbrance unless really desired, and he writes of
observing Saturn therewith. Whatever may have been the reason, it seems
probable from the rapidity with which he threw himself into astronomy
and into its planetary branch, that at least he had something of the
kind in his mind before he returned from Japan in the autumn of 1893.




                               CHAPTER IX
                      THE OBSERVATORY AT FLAGSTAFF


When, returning from Japan late in 1893, Percival Lowell found himself
quickly absorbed by astronomical research, he was by no means without
immediate equipment for the task. His mathematical capacity, that in
college had so impressed Professor Benjamin Peirce, had not been allowed
to rust away; for, when at home, he had kept it bright in the
Mathematical and Physical (commonly called the M. P.) Club, a group of
men interested in the subject, mainly from Harvard University and the
Massachusetts Institute of Technology. So fresh was it that we find him
using, at the outset, with apparent ease his calculus—both differential
and integral—tools that have a habit of losing edge with disuse.
Physically, also, he had a qualification of great importance for the
special work he was to undertake,—that of perceiving on the disks of the
planets, very fine markings close to the limit of visibility; for the
late Dr. Hasket Derby, then the leading practitioner in Ophthalmology in
Boston, told Professor Julian Coolidge that Percival’s eyesight was the
keenest he had ever examined.

One essential remained, to find the best atmosphere for his purpose. In
entering our air the rays of light from the stars are deflected, that is
bent, and bent again when they strike a denser or less dense stratum.
But these strata are continually changing with currents of warmer or
colder air rising and falling above the surface of the earth, and hence
the rays of light are being shifted a little from side to side as they
reach us. Everyone is familiar with the twinkling of the stars, caused
in this way; for before entering our atmosphere their light is perfectly
steady. Moreover, everyone must have observed that the amount of
twinkling varies greatly. At times it is unusually intense, and at
others the stars seem wonderfully still. Now, although the planets,
being near enough to show a disk visible through a telescope, do not
seem to twinkle, the same thing in fact occurs. The light is deflected,
and the shaking makes it very difficult to see the smaller markings.
Imagine trying to make out the detail on an elaborately decorated plate
held up by a man with a palsied hand. The plate would be seen easily,
but for the detail one would wish it held in a steadier grasp, and for
observing the planets this corresponds to a steadier atmosphere.

Percival’s own account of the reason for his expedition of 1894 to
observe the planet Mars, why he selected Flagstaff as the site, what he
did there and how the plan developed into the permanent observatory that
bears his name were told in what was intended to be an introduction to
the first volume of the Annals of the Observatory. Perhaps owing to the
author’s illness in the last years of the century this statement was
mislaid and was not found until February 22, 1901. It is here printed in
full.


                    Annals of the Lowell Observatory
                              INTRODUCTION

In the summer of 1877 occurred an event which was to mark a new
departure in astronomy,—the detection by Schiaparelli of the so-called
canals of the planet Mars. The detection of these markings has led to
the turning over of an entirely new page in cosmogony.

Schiaparelli’s discovery shared the fate of all important astronomical
advances,—even Newton’s theory of gravitation was duly combatted in its
day,—it, and still more the possibilities with which it was fraught,
distanced the comprehension of its time. In consequence, partly from
general disbelief, partly from special difficulty, no notable addition
was made to Schiaparelli’s own work until 1892, when Professor W. H.
Pickering attacked the planet at the Boyden Station of the Harvard
Observatory at Arequipa, Peru, and made the next addition to our
knowledge of our neighbor world.

Intrinsically important as was Pickering’s work, it was even more
important extrinsically. Schiaparelli’s discoveries were due solely to
the genius of the man,—his insight, not his eyesight, for at the
telescope eyes differ surprisingly little, brains surprisingly much;
Pickering’s brought into coöperation a practically new instrument, the
air itself. For at the same time with his specific advance came a
general one,—the realization of the supreme importance of atmosphere in
astronomical research. To the Harvard Observatory is due the first
really far-reaching move in this direction, and to Professor W. H.
Pickering of that observatory the first fruits in carrying it out.

It was at this stage in our knowledge of the possibilities in planetary
work and of the means to that end, in the winter of 1893-94, that the
writer determined to make an expedition which included the putting up of
an observatory for the primary purpose of studying, under the best
procurable conditions, the planet Mars at his then coming opposition,—an
opposition at which the planet, though not quite so close to us as in
1892, would be better placed for northern observers. In this expedition
he associated with himself Prof. W. H. Pickering and Mr. A. E. Douglass.

The writer had two objects in view:

1st, the determination of the physical condition of the planets of our
solar system, primarily Mars;

2d, the determination of the conditions conducive to the best
astronomical observations.

How vital was the inter-connection of the two was demonstrated by the
results.

Important as atmosphere is to any astronomical investigation, it is
all-important to the study of the planets. To get, therefore, within the
limits of the United States—limits at the time for several reasons
advisable—as steady air as possible, Prof. W. H. Pickering, who had
already had experience of Southern California as well as of Arequipa,
Peru, proposed Arizona as the most promising spot. Accordingly, Mr. A.
E. Douglass left Boston in March, 1894, with a six-inch Clark refractor
belonging to the writer, to make a test of the seeing throughout the
Territory. From his report, Flagstaff was selected for the observatory
site.

Flagstaff, then a town of eight hundred inhabitants, lies on the line of
the Atlantic and Pacific Railroad, in the centre of the great plateau of
northern Arizona, half way across the Territory from east to west, and
two fifths way down from north to south. This plateau, whose mean
elevation is between 6000 and 7000 feet, is a great pine oasis a hundred
miles or more in diameter, rising some 3000 feet from out the Arizona
desert. It culminates in the mass known as the San Francisco Peaks, ten
miles north of Flagstaff, whose highest summit rises 12,872 feet above
the level of the sea.[9]

The spot chosen was the eastern edge of the mesa (table-land) to the
west of Flagstaff. The site lay open to the east and south, and was
shielded on the north by the San Francisco Peaks. The distance from the
observatory to Mt. Agassiz, the most conspicuous of the Peaks from the
Flagstaff side, was about eight miles and three fifths in an air-line,
and the distance to the town about a mile and a quarter. As soon as the
site was selected, the town very kindly deeded to the observatory a
piece of land and built a road up to it.

The observatory stood 350 feet above the town, and 7250 feet above the
level of the sea, in latitude 35° 11′ north and longitude 111° 40′ west.

Prof. W. H. Pickering, to whose skill and ability was chiefly due the
successful setting up of the observatory, suggested arrangements with
Brashear for the use of an eighteen-inch refractor which Brashear had
recently constructed,—the largest glass to be had at the
time,—arrangements which were accordingly made. He then devised and
superintended the construction of a dome intended to be of a temporary
character, which worked admirably. The upper part of it was made in
sections in Cambridgeport, Mass., and then shipped West, the lower part
being constructed according to his specifications on the spot, under the
superintendence of Mr. Douglass.

The telescope was supported on one of the Clark mountings. The
bed-plate, clock-work, and a twelve-inch telescope were leased of the
Harvard College Observatory, and the mounting then altered by Alvan
Clark & Sons to carry both the twelve and the eighteen-inch telescopes.

Six weeks from the time ground was broken, on April 23, 1894, regular
observations with the eighteen-inch were begun.

The results of the year’s work surpassed anticipation. Details invisible
at the average observatory were presented at times with copper-plate
distinctness, and, what is as vital, the markings were seen hour after
hour, day after day, month after month. First sight; then system; and
the one of these factors was as fundamental to the results as the other.
Systematic work, first made possible and then properly performed, was
the open sesame to that most difficult branch of astronomical
observations, the study of our nearest neighbors in the universe.

The chief results obtained were:—

1st, the detection of the physical characteristics of the planet Mars to
a degree of completeness sufficient to permit of the forming of a
general theory of its condition, revealing beyond reasonable doubt first
its general habitability, and second its particular habitation at the
present moment by some form of local intelligence;

2d, corroboration and extension by Professor Pickering of his
discoveries at Arequipa with regard to the forms of Jupiter’s
Satellites;[10]

3d, the discovery and study by Mr. Douglass of the atmospheric causes
upon which good seeing depends.

It is of the observations connected with the first of these that the
present volume of the Annals alone treats.

As the publication of this volume has been so long delayed, it seems
fitting to add here a brief continuation of the history of the
observatory to the present time.

The results of the expedition in 1894, in the detection of planetary
detail, turned out to be so important an advance upon what had
previously been accomplished that the writer decided to form of the
temporary expedition a permanent observatory. Accordingly, he had Alvan
Clark & Sons make him a twenty-four-inch refractor, which fate decided
should be their last large glass; the Yerkes glass, although not yet in
operation at the time this goes to press, having been finished at nearly
the time his was begun. The glass received from Mantois happened to be
singularly flawless and its working the same. It was made twenty-four
inches in clear aperture, and of a focal length of thirty-one feet.
Alvan G. Clark accompanied the writer to Flagstaff and put the glass in
place himself.

The mounting for the telescope was likewise made by the Clarks. Rigidity
was the prime essential, in order to secure as stable an image as
possible, and this has been admirably carried out, the mounting being
the heaviest and most stable for a glass of its size yet made.

In July, 1896, Dr. T. J. J. See joined the observatory, to continue
there the line of research for which he was already well known—the study
of the double stars. This added to the two initial objects of the
observatory a third,—

3d, the study of double-star systems, including a complete catalogue of
those in the southern heavens.

During the summer and autumn of 1896 the importance of good atmosphere
was further demonstrated in an interesting and somewhat surprising
quarter. The air by day was found to be as practicable as that by night.
While Mars was being studied by night, the study of Venus and Mercury
was taken up during the daytime systematically, and the results proved
as significant as had been those on Mars. Instead of the vague diffused
patches hitherto commonly recorded, both planets’ surfaces turned out to
be diversified by markings of so distinct a character as not only to
disclose their rotation periods but to furnish the fundamental facts of
the physical conditions of their surfaces. We know now more about
Mercury and Venus than we previously knew of Mars.

As the winter in Flagstaff is not so good as the summer, it was thought
well to try Mexico during that season of the year. Accordingly, a new
dome was made; the telescope was taken down; and dome, mounting, and
glasses were carried to Mexico and set up for the winter at Tacubaya, a
suburb of the City of Mexico, at an elevation of 7500 feet. There the
observatory received every kindness at the hands of the President, the
Government, and the National Observatory.

Observations at Mexico fully corroborated those at Flagstaff with regard
to both Mars, Mercury and Venus, and enabled Mr. Douglass to make the
first full determination of the markings on Jupiter’s third and fourth
satellites, thus fixing their rotation periods.

Dr. See in the mean time, who while at Flagstaff had discovered a very
large number of new doubles, in Mexico added to his list;...

With the spring the observatory was shipped back again to Flagstaff.

Of the particular results in planetary work obtained, several papers
have been published in various astronomical journals, while of them
subsequent volumes of the Annals will speak in detail. In the meantime
two general conclusions to which they have led the writer may, as
possessing future interest, fittingly be mentioned here:

1st, that the physical condition of the various members of our solar
system appears to be such as evolution from a primal nebula would
demand;

2d, that what we call life is an inevitable detail of cosmic evolution,
as inherent a property of matter from an eventual standpoint as
gravitation itself is from an instant one: as a primal nebula or
meteoric swarm, actuated by purely natural laws, evolves a system of
bodies, so each body under the same laws, conditioned only by size and
position, inevitably evolves upon itself organic forms.

The reasons for the first of these conclusions have sprung directly from
the writer’s study of the several members of our own solar system; his
reason for the second, upon the further facts,—

1st, that where the physical conditions upon these bodies point to the
apparent possibility of life, we find apparent signs of life;

2d, where they do not, we find none.

This implies that, however much its detail may vary, life is essentially
the same everywhere, since we can reason apparently correctly as to its
presence or absence, a result which is in striking accord with the
spectroscopic evidence of a practical identity of material.


Evidently the expedition to observe Mars was undertaken quite suddenly,
but if it was to be made at all it must be done quickly. Anyone, however
unfamiliar with astronomy, will perceive that two planets revolving
about the sun in independent orbits will be nearest together when they
are on the same side of the sun and farthest apart when on opposite
sides of it, and that the difference is especially great if, as in the
case of the earth and Mars, their orbits are not far apart, for when on
the same side the separation is only the difference of their distances
from the sun, and when on opposite sides it is the sum of those
distances. Moreover, Mars being outside of the Earth its whole face is
seen in the full light of the sun when both bodies are on the same side
of it. Now such a condition, called opposition, was to occur in the
summer after Percival’s return from Japan, and therefore there was no
time to spare in getting an observatory ready for use.

From the experience of others elsewhere, Percival was convinced that the
most favorable atmospheric situations would lie in one of the two desert
bands that encircle a great part of the Earth, north and south of the
equator, caused by the sucking up of moisture by the trade winds; and
that a mountain, with the currents of air running up and down it, did
not offer so steady an atmosphere as a high table-land. The height is
important because the amount of atmosphere through which the light
travels is much less than at sea level. He was aware that the best
position of this kind might well be found in some foreign country; but
again there was no time to search for it, or indeed to build an
observatory far away, if it must be equipped by the early summer. The
fairly dry and high plateau of northern Arizona seemed, therefore, to
offer the best chance of a favorable site for this immediate and
temporary expedition.

With the aid of suggestions by Professor William H. Pickering, who knew
what was needed in observing Mars, he sent Mr. Douglass, with the
six-inch telescope brought back from Japan, to Arizona to inspect the
astronomic steadiness of the atmosphere. The instructions, apparently
drawn up by Professor Pickering, were dated February 28th, directing him
to observe on two nights each at Tombstone, Tucson and Phoenix; and
Percival, keeping in constant touch with Mr. Douglass by letter and
telegraph, added among other places Flagstaff. This was shortly followed
by instructions about constructing the circular vertical part of the
dome for the observatory by local contract as soon as the site was
selected, while the spherical part above, which was to be of parallel
arches covered with wire netting and canvas, was being made in the East
and to be shipped shortly. Meanwhile the pier was being built by Alvan
Clark & Sons (who had made most of the large telescopes in this country)
and the mounting for both the eighteen-inch and the twelve-inch
telescope thereon, balancing each other. Mr. Douglass was to report
constantly; and in April Percival wrote him to take a photograph of the
site of the observatory “now,” then every day as the work progressed,
and have the negatives developed, a blue print made of each as speedily
as possible and sent East. All this is stated here to show the speed,
and at the same time the careful thought, with which the work was done.
Percival and his colleagues came as near as possible to carrying out the
principle, “when you have made up your mind that a thing must be done,
and done quickly, do it yesterday.”

In fact Percival did not select any of the three places first examined,
but on consideration of Mr. Douglass’ reports preferred Flagstaff; and
his choice has been abundantly confirmed by the pioneering problems
undertaken there, and by the fact that this site was retained for the
later permanent Observatory. Everyone, indeed, deserves much credit for
the rapid work done at such a distance from principals busy with the
preparation of the instruments. It was characteristic of Percival that
he got the very best out of those who worked with and under him.

Although the closest point of the opposition did not occur until the
autumn, the two planets, travelling in the same direction, were near
enough together for fair observation some months earlier; and on May
28th, arriving at Flagstaff, Percival writes to his mother: “Here on the
day. Telescope ready for use tonight for its Arizonian virgin view....
After lunch all to the observatory where carpenters were giving their
finishing touches.... Today has been cloudy but now shows signs of a
beautiful night and so, not to bed, but to post and then to gaze.” The
sky was not clear that night, for an unprecedented rain came and lasted
several days, falling through the still uncanvased dome on Professor
Pickering and Percival, who had been lured by a “fairing” sky into
camping out there in the evening to be on time for the early rising
Mars. But it was not long before the weather cleared and the strenuous
work began. As the observatory was a mile and a half from the hotel in
the town, and uphill, it was uncomfortable to arrive there at three
o’clock in the morning, the hour when at that season Mars came in sight.
So in the summer a cottage was built hard by the dome, where they could
sleep and get their meals.

The observations were, of course, continuous throughout the rest of the
year; and except for two trips East on business, one for a few weeks at
the end of June, another in September, and a few days in Los Angeles,
Percival was there all the time. As usual he worked furiously; for
beside observing most of the night he spent much of the day writing
reports and papers, making drawings for publication in scientific and
other periodicals, and investigating collateral questions that bore upon
their significance; and while he had computers for mechanical detail, he
and his colleagues had to prepare and supervise their work. To his
mother he wrote, as a rule, every day; and in some of these letters he
gave an account of his time. On September 2nd, he writes of being up the
greater part of the night, and naturally perpetually sleepy. “But the
number of canals increases encouragingly—in the Lake of the Sun region
we have seen nearly all Schiaparelli’s and about as many more.” On
October 10th: “Observed the better part of last night, after being
welcomed by everybody—and have been as a busy as a beaver today, writing
an article, drawing for ditto etc, etc.”; and, two days later, “Chock
full of work; scrabbling each day for the post—proof etc. Mr. Douglass
is now on the hill observing Mercury. We all dine there at seven. Then I
take Mars and at 3 A.M. Professor Pickering, Jupiter. So you see none of
the planets are neglected.”

In one of these letters he encloses a clipping from a San Francisco
newspaper satirizing Professor Holden for saying that the canals of Mars
reported at Flagstaff were not confirmed by observations at Mount
Hamilton. Denial or doubt that he had really seen what—after many
observations confirmed by those of his colleagues—he reported as seen
always vexed Percival, and naturally so. Yet they were not uncommon and
sometimes attributed to defective vision. He was well aware that while a
belief that a thing exists may make one think he has seen it when he has
not, yet it is also true that one person perfectly familiar with an
object sought will find it when another, unacquainted with its precise
appearance, will miss it altogether. Everyone knows that people in the
habit of looking for four-leaved clovers are constantly picking them
while others never see them; or that a skilled archaeologist finds
arrowheads with much greater facility than a tyro, who will, however,
improve rapidly with a little experience; and all this is especially
true of things near the very limit of visibility. Gradually more and
more observers began to see the finer markings and the canals on Mars,
until finally the question of their existence was set at rest when it
became possible to photograph them.

But in spite of work and vexation the life was far from dull, for the
observatory was as hospitable as its limited quarters would allow.
Visitors were attracted by its growing reputation, and on August 25th he
writes: “Just as we were plodding up there last evening in the dark we
heard a carriage-full of folk coming down. We suspected what they had
been after and were not surprised when they challenged us with ‘Are you
observatory people?’ It seems they were, as they informed us
pathetically, people from the East and had gone up to look through the
glass, if they might, before taking the train at 12.30 that night. Of
course we could not resist their appeals and so, though we had thought
to turn in betimes because of early observations in the morning,
entertained these angels—half of them were women—on ‘just like diamonds’
as they said of the stars. The out-of-focus views pleased them the
most—as turns out to be the case generally. This morning when I went to
take Pickering’s place I found another angel in the shape of a Colorado
man, out here for his health, in the dome with Pickering—a nice fellow
he turned out. It was then 4 h. 8 m. o’clock in the morning,—a matutinal
hour for a man to trudge a mile and a half on no breakfast up to an
observatory on a hill—That shows real astronomical interest. He was
rewarded gastronomically with some coffee of my brewing, all three of us
breakfasting standing by the platform.”

There were occasional picnics and trips to the cave dwellings, the Grand
Cañon, the petrified forest and other sights. Moreover, Percival greatly
enjoyed the scenery about Flagstaff, and took an interest in the people
of the town, although well aware of inexperience in some matters. On
October 13th he says: “There was a grand republican rally last night and
the young Flagstaff band that is learning to play in tune serenaded the
speaker of the occasion under the hotel windows in fine style. When you
knew the air beforehand you could follow it with enthusiasm.”




                               CHAPTER X
                                  MARS


Meanwhile the work of the Observatory went on, partly in the direction
of the special lines of the several observers, but mainly in that of the
founder whose interest was then predominantly planetary, especially in
Mars; and from this the site of the dome came to be called Mars Hill.
The clear atmosphere yielded the results that had been hoped for, and
much was discovered about the planets, their period of rotation,
satellites etc., but above all were the Martian observations fruitful.
There the object was to watch the seasonal changes beginning with the
vernal equinox, or spring of the southern hemisphere, the one inclined
toward the earth when the two bodies approach most closely, and follow
them through the summer and autumn of our neighbor. For those not
familiar with the topography of Mars it may be said that the greater
part of its surface is a reddish or orange color interspersed with
patches or broken bands of a blue, or greenish blue, in the southern
temperate zone. These had been supposed to be seas, and are still known
by names recalling that opinion, while the lighter regions derived their
nomenclature from the theory that they are continents or islands
standing out of the water. This is confusing, but must be borne in mind
by anyone who looks at a map of the planet and tries to understand the
meaning of the terms. There are several reasons for thinking that the
dark areas are not seas: one that they change in depth of color with the
seasons; another that light reflected from water is polarized and in
this case it is not; also they never show a brilliant specular
reflection of the Sun as seas would do.

Now in the winter of the Martian southern hemisphere the region around
that pole turned white, that is it became covered by a mantle appearing
like snow or ice, and as the summer advanced this became less and less
until it disappeared altogether. Meanwhile there formed around it a dark
mass that spread downwards, toward the temperate zone and into the
bluish areas there, which assumed a darker hue. After the deepening
color had reached the edge of the wrongly called sea, very thin straight
lines appeared proceeding from it into the lighter reddish regions
(mistaken for continents) toward the equator, and increased rapidly in
number until there was a great network of them. It very often happened
that more than two of these intersected at the same point, and when that
occurred there usually came a distinct dot much larger than the
thickness of the lines themselves. After this process was fairly under
way the dark areas faded down again, and then similar fine lines
appeared in them, connecting with those in the light areas, and
apparently continuing toward the pole. Moreover, some of the lines in
the light region doubled, that is two parallel lines appeared usually
running in this case not to the centres, but to the two sides of the
dark dots. It is essential to add that the limit of thickness for any
line on Mars to be seen by their telescopes was estimated at about
fifteen miles, so that these fine lines must have been at least of that
width.

Such is in brief the outline of that which the observers saw. What did
these things mean? What was the interpretation of the phenomena, their
opinion on the causes and operation? This, with the details of the
observations, is given by Percival in his book “Mars,” written
immediately after this first year of observation, the preface bearing
the date November, 1895. But it must not be supposed that he started to
observe with any preconceived idea that the planet was inhabited, or
with the object of proving that the so-called canals were the work of
intelligent beings, for in the preface to the fourth edition he says:
“The theory contained in this book was conceived by me toward the end of
the first year’s work at Flagstaff. Up to that time, although the
habitability of Mars had been often suggested and strenuously opposed,
no theory based upon sufficient facts had ever been put forth that bound
the facts into a logical consistent whole—the final rivet perhaps was
when the idea of the oases occurred to me.” The oases were the dots at
the intersection of the fine lines which were called by Schiaparelli
“canali” and have retained the name canals.

“Mars” begins with a description of the planet, of its orbit, size and
shape, as compared with that of the Earth. By means of its trifling
satellites its mass was determined, and from this and its dimensions the
force of gravity at its surface, which was found to be a little over one
third of that on the Earth; so that living creatures, if any, could be
much larger than those of the same type here. From the markings that
could be seen on its face the period of rotation, that is the length of
the Martian day, was measured with great accuracy, being about forty
minutes longer than our own; while the Martian year, known from its
revolution round the sun, was about twice the length of ours. All this
led to a calculation of the nature of the planet’s seasons, which for
its southern hemisphere—the one turned toward the Earth when the two
bodies are near together as in 1894—gave a long cold winter and a summer
short and hot.

He then takes up the question of atmosphere, which, with water, is
absolutely necessary for life, and even for physical changes of any kind
“when once what was friable had crumbled to pieces under the alternate
roasting and refrigerating, relatively speaking, to which the body’s
surface would be exposed as it turned round on its axis into and out of
the sun’s rays. Such disintegration once accomplished, the planet would
roll thenceforth a mummy world through space,” like our own moon, as he
says, where, except for the possible tumbling in of a crater wall, all
is now deathly still. But on Mars changes occur on a scale vast enough
to be visible from the Earth, and he tells in greater detail the first
of those noted in the preceding summary, the formation and melting of
the polar snows. Moreover, a change was observed in the diameter of the
planet, which could be explained only by the presence of a twilight
zone, and this meant an atmosphere refracting the rays of the sun, a
phenomenon that he dwells upon at some length. He then turns to the
nature of the atmosphere, and from the relative cloudlessness and the
lesser force of gravity concludes that its density is probably about one
seventh of that on the surface of the Earth. So much for its quantity.
For its quality he considers the kinetic theory of gases, and calculates
that in spite of its lesser gravity it could retain oxygen, nitrogen,
water vapor, and in fact all the elements of our atmosphere.

He next considers the question of water, the other essential to the
existence of life, animal or vegetable; the phenomenon of the
diminution, and final disappearance, of the polar cap, the behavior of
the dark blue band which formed along it; and says: “That the blue was
water at the edge of the melting snow seems unquestionable. That it was
the color of water; that it so persistently bordered the melting snow;
and that it subsequently vanished, are three facts mutually confirmatory
to this deduction. But a fourth bit of proof, due to the ingenuity of
Professor W. H. Pickering, adds its weight to the other three. For he
made the polariscope tell the same tale. On scrutinizing the great bay
through an Arago polariscope, he found the light coming from the bay to
be polarized. Now, to polarize the light it reflects is a property, as
we know, of a smooth surface such as that of water is.” The great bay of
which he speaks is the widest part of the blue band. He discusses the
suggestion that the white cap is due, as had been suggested, to
congealed carbonic acid gas instead of ice or snow from water, and
points out that with the slight density of the Martian atmosphere this
would require a degree of cold impossible under the conditions of the
planet; an important conclusion later fully confirmed by radiometric
measures at Flagstaff and Mt. Wilson.

Assuming therefore that the polar cap is composed of snow or ice, he
traced its history, as observed more closely than ever before at
Flagstaff, and gives a map of its gradual shrinking and final
disappearance, with the corresponding condition of the blue water at its
edge. All this from June 3 to October 13 of our year, or from May 1 to
July 13 of the Martian seasons, and this was the first time the cap had
been seen to vanish wholly. It is interesting to note that in the early
morning of June 8 “as I was watching the planet, I saw suddenly two
points like stars flash out in the midst of the polar cap. Dazzlingly
bright upon the duller white background of the snow, these stars shone
for a few moments and then slowly disappeared. The seeing at the time
was very good. It is at once evident what the other-world apparitions
were,—not the fabled signal lights of Martian folk, but the glint of
ice-slopes flashing for a moment earthward as the rotation of the planet
turned the slope to the proper angle ... nine minutes before they reach
Earth they had ceased to be on Mars, and, after their travel of one
hundred millions of miles, found to note them but one watcher, alone on
a hill-top with the dawn.”

Seven years before Green, at Madeira, had seen the same thing at the
same spot on the planet, drawn the same conclusion, and named the
heights the Mitchell Mountains, after the man who had done the like in
1846. Later the blue belt below the cap turned brown; “of that mud-color
land does from which the water has recently been drained off,” and at
last, “where the polar ice-cap and polar sea had been was now one ochre
stretch of desert.”

The geography of Mars he describes, but what he tells cannot be made
intelligible without the twelve successive views he gives of the planet
as it turns around; while the names of places, given in the main by
Schiaparelli, are based in large part on the mistaken impression that
the dark regions were seas and bays, the light ones continents and
islands. “Previous to the present chart,” Percival writes, “the most
detailed map of the planet was Schiaparelli’s, made in 1888. On
comparison with his, it will be seen that the present one substantially
confirms all his detail, and adds to it about as much more. I have
adopted his nomenclature, and in the naming of the newly found features
have selected names conformable to his scheme, which commends itself
both on practical and on poetic grounds.” By this, of course, he does
not mean to commend naming the dark areas as seas, for his description
of the features on the planet’s surface is followed by a statement of
the reasons, apparently conclusive, for assuming that the blue-green
regions cannot be seas, but must be vegetation; while the reddish ochre
ones are simply desert.

“Upon the melting of its polar cap, and the transference of the water
thus annually set free to go its rounds, seem to depend all the seasonal
phenomena on the surface of the planet.

“The observations upon which this deduction is based extend over a
period of nearly six months, from the last day of May to the 22d of
November. They cover the regions from the south pole to about latitude
forty north. That changes analogous to those recorded, differing,
however, in details, occur six Martian months later in the planet’s
northern hemisphere, is proved by what Schiaparelli has seen.” In order
that the reader may not be confused, and wonder why the changes at the
north pole do not begin shortly after those in the southern hemisphere
are over, he must remember that the Martian year has 687 days, and is
thus nearly twice as long as ours, or in other words that the period of
these observations covered only about four months in Mars.

“So soon as the melting of the snow was well under way, long straits, of
deeper tint than their surroundings, made their appearance in the midst
of the dark areas,” although the dark areas were then at their darkest.
“For some time the dark areas continued largely unchanged in appearance;
that is, during the earlier and most extensive melting of the snow-cap.
After this their history became one long chronicle of fading out. Their
lighter parts grew lighter, and their darker ones less dark. For, to
start with, they were made up of many tints; various shades of
blue-green interspersed with glints of orange-yellow.... Toward the end
of October, a strange, and, for observational purposes, a distressing
phenomenon took place. What remained of the more southern dark regions
showed a desire to vanish, so completely did those regions proceed to
fade in tint throughout.” He points out that such a change is
inexplicable if the dark areas were water, for there was no place for it
to go to. “But if, instead of being due to water, the blue-green tint
had been due to leaves and grasses, just such a fading out as was
observed should have taken place as autumn came on, and that without
proportionate increase of green elsewhere; for the great continental
areas, being desert, are incapable of supporting vegetation, and
therefore of turning green.” By the continental areas he meant the
barren regions, formerly thought to stand out from seas in contrast with
the darker ones supposed to be water.

“Thus we see that several independent phenomena all agree to show that
the blue-green regions of Mars are not water, but, generally at least,
areas of vegetation; from which it follows that Mars is very badly off
for water, and that the planet is dependent on the melting of its polar
snows for practically its whole supply.

“Such scarcity of water on Mars is just what theory would lead us to
expect. Mars is a smaller planet than the Earth, and therefore is
relatively more advanced in his evolutionary career.” And as a planet
grows old its water retreats through cracks and caverns into its
interior. The so-called seas were, he thinks, once such, and “are still
the lowest portions of the planet, and therefore stand to receive what
scant water may yet travel over the surface.” With this agrees the fact
that the divisions between the dark and light areas run south-east
north-west; as they would if made by currents in water flowing from the
pole toward the equator.

“Now, if a planet were at any stage of its career able to support life,
it is probable that a diminishing water supply would be the beginning of
the end of that life, for the air would outlast the available water.[11]
...

“Mars is, apparently, in this distressing plight at the present moment,
the signs being that its water supply is now exceedingly low. If,
therefore, the planet possess inhabitants, there is but one course open
to them in order to support life. Irrigation, and upon as vast a scale
as possible, must be the all-engrossing Martian pursuit....

“At this point in our inquiry, when direct deduction from the general
physical phenomena observable on the planet’s surface shows that, were
there inhabitants there, a system of irrigation would be an
all-essential of their existence, the telescope presents us with perhaps
the most startling discovery of modern times,—the so-called canals of
Mars.”

He then takes up these so-called canals or lines which start from the
edge of the blue-green regions, proceed directly to what seem centres in
the middle of the ochre areas, where they meet other lines that come, he
says, “with apparently a like determinate intent. And this state of
things is not confined to any one part of the planet, but takes place
all over the reddish-ochre regions,” that is the arid belt of the
planet. “Plotting upon a globe betrays them to be arcs of great circles
almost invariably, even the few outstanding exceptions seeming to be but
polygonal combinations of the same.” These two facts, that the lines are
great circles, or the shortest distance between points on the surface of
the planet, and that several of them often meet at the same place, must
be borne in mind, because they are essential elements in his argument
that they are the result of an intelligent plan.

The lines are of enormous length, the shortest being 250 miles, and the
longest 3,540, and at times three, four, five, and even seven come
together at one spot. By them the whole region is cut up, and how many
there may be cannot now, he says, be determined, for the better the air
at the observatory the more of them become visible. At Flagstaff they
detected 183, seen from once to 127 times, and there were in the
aggregate 3,240 records made of them.[12]

In seeking for the origin of the lines he begins by discarding natural
causation on the ground first of their straightness, and second of their
uniform width, regularities not to be found to any such a degree in the
processes of nature. His third ground is “that the lines form a system;
that, instead of running anywhither, they join certain points to certain
others, making thus, not a simple network, but one whose meshes connect
centres directly with one another.... If lines be drawn haphazard over
the surface of a globe, the chances are ever so many to one against more
than two lines crossing each other at any point. Simple crossings of two
lines will of course be common in something like factorial proportion to
the number of lines; but that any other line should contrive to cross at
the same point would be a coincidence whose improbability only a
mathematician can properly appreciate, so very great is it.... In other
words, we might search in vain for a single instance of such encounter.
On the surface of Mars, however, instead of searching in vain, we find
the thing occurring _passim_; this _a priori_ most improbable
rendezvousing proving the rule, not the exception. Of the crossings that
are best seen, all are meeting places for more than two canals.”

He then takes up the question of cracks radiating from centres of
explosion or fissure, and points out that such cracks would not be of
uniform breadth. There are cracks on the moon which look like cracks,
while the lines on Mars do not. Moreover, the lines fit into one another
which would not be true of cracks radiating from different centres. The
lines cannot be rivers for those would not be the same width throughout,
or run on arcs of great circles. Nor can the lines be furrows ploughed
by meteorites, since these would not run straight from one centre to
another; in short the objection from the infinitesimal chance of several
lines crossing at the same point applies. “In truth,” he concludes, “no
natural theory has yet been advanced which will explain these lines.”

The development, or order in the visibility, of the canals throws light
on their nature. Early in the Martian spring they were invisible, then
those nearest to the melting snows of its south pole appeared, and in a
general succession those farther and farther away; but when they did
appear they were always in the same place where they had been seen
before. Each canal, however, did not darken all at once, but gradually;
and this he accounts for by saying that what we see is not water but
vegetation which takes time to develop. “If, therefore, we suppose what
we call a canal to be, not the canal proper, but the vegetation along
its banks, the observed phenomena stand accounted for. This suggestion
was first made some years ago by Professor W. H. Pickering.

“That what we see is not the canal proper, but the line of land it
irrigates, disposes incidentally of the difficulty of conceiving a canal
several miles wide. On the other hand, a narrow, fertilized strip of
country is what we should expect to find; for, as we have seen, the
general physical condition of the planet leads us to the conception, not
of canals constructed for waterways,—like our Suez Canal,—but of canals
dug for irrigation purposes. We cannot, of course, be sure that such is
their character, appearances being often highly deceitful; we can only
say that, so far, the supposition best explains what we see. Further
details of their development point to this same conclusion.” Such as
that with time they darken rather than broaden.

To the objection that canals could not be built in straight lines
because of mountain ranges he replies that the surface of Mars is
surprisingly flat, and this he proves by careful observations of the
terminator, that is the edge of that part of the planet lighted by the
Sun, where any considerable sudden changes of elevation on the surface
of the planet would appear, and do not.

He then tells of the discovery by Mr. Douglass of the canals in the dark
regions toward the south pole. They could not be seen while those
regions remained dark, but when they faded out the canals became
visible, and supplied the missing link explaining how the water from the
melting polar cap was conveyed to the canals in the arid space north and
south of the equator. Mr. Douglass found no less than forty-four of
them, almost all of which he saw more than once, one on as many as
thirty-seven occasions.

Then came the phenomenon that convinced Percival of an artificial system
of irrigation: “Dotted all over the reddish-ochre ground of the desert
stretches of the planet ... are an innumerable number of dark circular
or oval spots. They appear, furthermore, always in intimate association
with the canals. They constitute so many hubs to which the canals make
spokes”; and there is not a single instance of such a spot, unconnected
by a canal, and by more than one, with the rest of the system. These
spots are in general circular, from 120 to 150 miles in diameter, and
make their appearance after, but not long after, the canals that lead to
them, those that appear first becoming after a time less conspicuous,
those seen later more so. In short they behave as oases of vegetation
would when a supply of water had reached them, and thus give “an end and
object for the existence of canals, and the most natural one in the
world, namely, that the canals are constructed for the express purpose
of fertilizing the oases.... This, at least, is the only explanation
that fully accounts for the facts. Of course all such evidence of design
may be purely fortuitous, with about as much probability, as it has
happily been put, as that a chance collection of numbers should take the
form of the multiplication table.” He does not fail to point out that
great circles for the canals, and circular shapes for the oases, are the
forms most economical if artificially constructed; nor does his
reasoning rest upon a small number of instances, for up to the close of
observations at that time fifty-three oases had been discovered.

Finally he deals with the corroborating phenomena of double canals and
the curious dark spots where the canals in the dark regions debouch into
those that run through the deserts.

In his conclusion he sums up his ideas as follows:

“To review, now, the chain of reasoning by which we have been led to
regard it probable that upon the surface of Mars we see the effects of
local intelligence. We find, in the first place, that the broad physical
conditions of the planet are not antagonistic to some form of life;
secondly, that there is an apparent dearth of water upon the planet’s
surface, and therefore, if beings of sufficient intelligence inhabited
it, they would have to resort to irrigation to support life; thirdly,
that there turns out to be a network of markings covering the disk
precisely counterparting what a system of irrigation would look like;
and, lastly, that there is a set of spots placed where we should expect
to find the lands thus artificially fertilized, and behaving as such
constructed oases should. All this, of course, may be a set of
coincidences, signifying nothing; but the probability points the other
way.”

Such was the harvest of facts and ideas garnered from Mars at the
Observatory during this summer of tireless watching. Both the facts and
the conclusions drawn from them were received with incredulity by
astronomers whose atmospheres and unfamiliarity with the things to be
observed hindered their seeing the phenomena, and to whom the
explanations seemed fantastic. With more careful observation skepticism
about the phenomena decreased, one observer after another seeing the
change of color on the planet, the growth of vegetation, and in some
form the lines and the dots, although many skilled observers still see
them as irregular markings rather than as fine uniform lines. The
hypothesis of artificial construction of the canals by intelligent
beings has met with much more resistance. It runs against the blade of
Occam’s razor, that nothing should be attributed to conscious
intelligent action unless it cannot be explained by natural forces.
Percival seems to have made a very strong argument against any natural
cause yet suggested, and a rational case for an intelligent agency if no
natural one can be found. There, for the present, his hypothesis may be
said to rest.

The favorable period for observation during the opposition of Mars
having come to an end, the two larger telescopes, which had been hired
or borrowed for the expedition, were returned in the spring to their
owners, the observatory at Flagstaff being dismantled, and the rest of
the apparatus brought East and stored; but plans for further work on
Mars were by no means given up; and Percival—bent on still better
equipment for the next opposition of Mars, in the summer of
1896—arranged with Alvan Clark & Sons for the manufacture of a 24-inch
refractor lens. The Clarks were then the most successful makers of large
lenses in the world; for up to that time it had not been possible to
cast and cool these large pieces of glass so that they were perfectly
uniform in density, and the art of the Clarks consisted in grinding and
rubbing the surface so as to make its slight departure from the
calculated curves compensate for any unevenness in density; and to a
less extent it is still necessary. It required a skill of eye and hand
unequalled elsewhere, and Percivals’ lens was one of the most perfect
they ever made.

Where the telescope should be set up was not yet decided; for it will be
remembered that he wanted to make his observations in any accessible
place in the world where the clearest, and especially the steadiest,
atmosphere would be found. As already explained, he believed this lay in
one of the two great desert belts that encircle the Earth north and
south of the equator; and, for practical purposes, that meant Arizona,
Mexico and South America in the Western Hemisphere, and the Sahara in
the Eastern. Mr. Douglass had therefore been sent—probably with the
faithful 6-inch telescope—to Mexico and South America, while Percival
proposed to examine the Sahara himself.




                               CHAPTER XI
            THE PERMANENT OBSERVATORY—INTERLUDES AND TRAVELS


The year following his return to Boston, at the end of November, 1894,
was filled with the arrangements for his new telescope and apparatus,
and in writing the book on Mars. At this time he lived at 11 West Cedar
Street, the little house he had bought some time before; for it was
characteristic that, while lavishing whatever was needed on his
observatory, he was modest in his expenditure on himself. By the end of
the year his book was published, his work for the coming observatory was
done, and he went to Europe; but his Mother had died in March, and the
daily stream of loving letters, which told about himself, had ceased to
flow.

On December 10, 1895, he sailed on the _Spree_ with Alvan G. Clark, the
last surviving brother of the telescope-making family. The voyage,
though very rough at times, was uneventful, until as they were entering
the Solent the vessel struck, and stuck fast, on Warden’s Ledge, just
inside the Needles. “Fault of the pilot” Percival recorded, “aged 73 and
bordering on imbecility.” With all his travels about and around the
world this is the nearest he ever came to shipwreck; nor was it for him
very near, for since the ship could not get herself clear tugs came down
the next day and took off the passengers, who were landed at Southampton
and went up to London. Two days later he was in Paris, and for nearly
three weeks he and Clark saw astronomical friends,—among others having
to lunch and dinner Edouard Mantois, the great glass manufacturer who
had cast the new 24-inch refractor for his telescope. Percival enjoyed a
most interesting dinner at the house of Flammarion, the astronomer and
novelist, who was devoted to Mars and had followed his work at
Flagstaff. As he wrote to his Father—“There were fourteen of us, and all
that could sat in chairs of the zodiac, under a ceiling of a pale blue
sky, appropriately dotted with fleecy clouds, and indeed most prettily
painted. Flammarion is nothing if not astronomical. His whole apartment,
which is itself au cinquieme, blossoms with such decoration.

“At the dinner I made the acquaintance of Miss Klumpke of the Paris
Observatory, who has just translated my last article for the Bulletin of
the Société Astronomique.”

In fact before he left Paris for Africa he gave a talk to that society,
on his observations of Mars. At Marseilles, meeting his old friend,
Ralph Curtis, they crossed to Algiers and made excursions to Boghari and
Biskra to test the atmosphere on the border of the Sahara. Not finding
this satisfactory, he organized a small private caravan of his own for a
journey of a few days into the desert, taking the telescope—doubtless
the faithful six-inch—on a mule. His going off by himself across country
seems to have worried his companions for fear he would lose his way; but
he always turned up in the afternoon, and in time to observe when the
stars came out. Curiously enough, he found that although the air was
very clear they twinkled badly, so that while the atmosphere was
transparent it was distinctly unsteady, for his purpose a very grave
defect which excluded North Africa from the possible sites for his
observatory. Satisfied on this point, he left Algiers in February.

From Marseilles he took the opportunity to visit Schiaparelli, to whom
he owed so much of the incentive to study Mars, and found him at his
observatory in Brera near Milan. With him he compared observations, much
to his own satisfaction. The veteran looked middle-aged, but did not
expect to make more discoveries, and said that at the preceding
opposition the weather had been so bad that he saw almost nothing. So
his mantle had definitely fallen on Percival when he began his
observations at Flagstaff the year before.

Leaving Milan he started to visit Leo Brenner, who was also interested
in Mars, and had his observatory at Lussinpiccolo, a rather inaccessible
spot on the eastern coast of the Adriatic. In getting there he was much
delayed by a heavy storm, and beguiled the time by working out a
mathematical theory of the tides. Finally, he decided to go by rail to
Pola, and thence by boat to Lussinpiccolo, where Brenner met him,
insisting that he should stay with them. They proved most hospitable and
kind, but he was not favorably impressed by the observatory or its work;
and after a stay of a few days he returned through Cannes, Paris and
London, sailing for America on March 19th, to land in New York on the
28th.

Meanwhile, the work on the lens and its apparatus had been finished; but
it could not be set up until he was there, and arriving at the end of
March there was no time to spare. For although the opposition of Mars
did not occur until December 10th the planets would then be far past
their nearest point, and there was much to see months before. In fact
he, with Clark, arrived at Flagstaff shortly after the middle of July,
and proceeded at once to put the glass into the telescope—no small
difficulty, for the tube was so tight a fit in the dome which had housed
the Brashear telescope that the lens had to be hoisted up and let into
it through the shutter opening,—“quite a job,” as he wrote, “for so
delicate and yet heavy a thing as a 24-inch lens.” However, it was
successfully done, and the next morning at half past two observing
began, and thereafter the dome knew no rest.[13]

In the letter last quoted he says that he has “taken a brand new house,
finished indeed after I arrived, a little gem of a thing.” Before long
he had three houses on the hill there, and began that succession of
charming hospitalities ending only with his life. Friends like Professor
and Mrs. Barrett Wendell and Professor Charles S. Sargent visited there,
while Professor Edward S. Morse and George R. Agassiz, who were
interested in his investigations, paid him long visits; and since
Flagstaff was on the direct road to Southern California, a paradise
becoming more and more fashionable, many others stopped off on the way
to see him and his observatory, whom he was always delighted to
entertain, for he had an unusual capacity for doing so without
interrupting the course of his work. Then there were excursions to the
cave dwellings, the petrified forest, and other places of interest in
the neighborhood, for he loved the country about him, and took pleasure
in showing it to others. Sometimes these trips were unusual. “We all
rode,” he writes to a friend, “twelve miles out into the forest on the
cow-catcher of a logging train, visited there a hole in the ground
containing, if you crawl down through the chinks in the rocks several
hundred feet, a thing we were not accoutered to do, real ice in
midsummer; came back on the cow-catcher; and immensely enjoyed the
jaunt. The acmes of excitement were the meeting of cattle on the track
who showed much more unconcern of us than we of them. Indeed it was
usually necessary for the fireman to get down and shoo them off....
Nevertheless we saw a real bull fight in a pretty little valley far from
men where Greek met Greek for the possession of the herd. The two
champions toed the line with great effect.” Nor did his interest in
literature abate, for a few weeks later he wrote to the same
correspondent: “Send me, an’ you love me, the best Chaucer at my
expense.”

Meanwhile the observations of Mars and the other planets went on with
success, and he was naturally gratified when his telescope revealed
something that others had failed to find, such as Professor “See’s
detection of the companion to Sirius which astronomers have been looking
for in vain since its immersion some years ago in the rays of its
primary due to its place in its orbit. The Lick hunted for it
unsuccessfully last year”; the last remark being pointed by the fact
that this rival had again been casting doubt upon his discoveries on
Mars.

He observed without a break all summer and autumn, but aware that the
atmosphere at Flagstaff was not so good in the winter, he decided to try
that of Mexico, and thither he went in December taking the 24-inch
telescope. Before the dome therefor was built he saw well with the
six-inch; but for the larger glass the results were on the whole
disappointing. Yet the observations in Mexico were by no means
unproductive. To his father he writes: “In addition to all that I have
told you before, Mr. Douglass has just made some interesting studies of
Jupiter’s satellites, seeing them even better than we did at Flagstaff,
and detecting markings on them so well that they promise to give the
rotation periods and so lead to another pregnant chapter in tidal
evolution.” And in another letter to him: “Mercury, Venus, Mars, and
Jupiter’s satellites have all revealed new things about themselves. I
intend to embody all of these things some day in a series of volumes on
the planets.” Meanwhile, as during the observations of two years before,
he was sending papers to various scientific journals, American and
foreign, about results obtained on Mars, Mercury and Venus; and about
this time Sir Robert Hart asked through Professor Headland permission to
translate “Mars” into Chinese. One may add that the first volume of the
“Annals of the Lowell Observatory” appeared that year (1897), the next
in 1900.




                              CHAPTER XII
                          ILLNESS AND ECLIPSE


But his personal hopes of contributing further to science, or diffusing
the knowledge learned, were destined to be sadly postponed. In the
spring he left Mexico, and the telescope was returned to Flagstaff in
May; but although he could stand observing day and night without
sufficient sleep while stimulated by the quest, the long strain proved
too much, and he came back to Boston nervously shattered. Such a
condition is not infrequent with scholars who work at high speed, and
although the diagnosis is simple the treatment is uncertain. The
physicians put him to bed for a month in his father’s house in
Brookline, a measure that he always thought a mistake, believing that he
would not have collapsed so completely under a different regimen. The
progress everyone knows who has seen it, a very slow regaining of
strength, with ups and downs, and after much discouragement—in his case
about three years—a return to normal health.

After the doctors let him up from bed he sought rest in divers places,
but the progress was slow and uneven, as it must be in such cases.
Naturally letters at this period are few, short and far between. Only
two, written to his father, appear to have been preserved, one from
Bermuda, January 22, 1898:

  “Dear Father:

  I enclose what I think you will like to see, a copy made for you of a
  letter just received. _Festina lente_ is nature’s motto for me, and I
  try to make _nulla vestigia retrorsum_.

                           Affectionately your son
                                                               Percival”

The copy enclosed is evidently of the letter from Professor Headland
conveying Sir Robert Hart’s request to translate “Mars” into Chinese.
The other letter is on January 17, 1899, with no place—date, and it
says: “Was much better; now can’t sleep well. So it wags.”

A year later, although not yet recovered, he was so much improved as to
plan with Professor Todd of Amherst an expedition to Tripoli to observe
a total eclipse of the sun. They took a 24-inch lens, from the
observatory at Amherst, with a very light tube for transportation in
four joints that would slip inside one another, and a device for
photographing the solar corona; the lens of the telescope being the
largest yet used in such an expedition. Sending the apparatus by
freight, they themselves sailed on the German Steamship _St. Paul_ from
New York on January 17, 1900. He had regained his humor, if nothing
else, for he heads his private journal of this exploit: “An Eclipse trip
to Tripoli being the sequel to The Valet and the Valetudinarian”—not
that he ever wrote anything under this last title, but it was a
reference to what he had been through in the preceding two and a half
years—and after inserting two flamboyant newspaper clippings, for which
he was not responsible, he writes: “Further notices there were of which
no notice need be taken; literary and professional murders all, of
various degrees of atrocity.”

After a few days in London, where he exchanged comments on the spectrum
of Mars with Sir William Huggins, he passed on to Paris, and then
Marseilles and Costabella where his widowed sister, Katharine Roosevelt,
was staying. The eclipse was not to occur until the end of May, but
there was much to be done in setting up the instruments, at which he was
not needed; so as he saw his sister off for Italy he also bade good-bye
for a time to Professor Todd, who left him to look up the telescopic
apparatus and get it in place at Tripoli, while he stayed to recuperate
for three months on the Riviera.

Here he found William James who, with his wife, was on a like quest to
recruit from a similar case of neurasthenia, and at the same time to
prepare his Gifford lectures. To his father Percival wrote on April 7:
“Professor William James is living here now and we see each other all
the time. He is pleased at having just been elected a corresponding
member of the Academy of Sciences of Berlin, more for his children’s
sake than his own. This when he thought he should never be able to work
again, and he wanted them to feel that their father had done something.
Now, however, he is stronger and polishes off some Gifford lectures
daily, a bit of it.” They saw much of each other, being highly
sympathetic physically and intellectually. Like himself, James had
recovered, or not lost, his sense of humor, and quoted a remark he had
heard “that ethics was a tardy consolation for the sins one had
neglected to commit.” And Percival was impressed by his saying that he
“considered Darwin’s greatness due to his great detail as increasing the
probabilities; showing again how mere detail, mere bulk impresses,
though probability be not furthered a bit.” The last part of the
sentence may be Percival’s own conclusion rather than that of James, but
it had clearly a bearing on his own minute study of the phenomena of
Mars.

On the Riviera he made a number of pleasant acquaintances and he was
well enough to enjoy seeing people; but, although he was writing a
memoir for the American Academy on Venus, he was not yet up to really
hard work. After trying in vain to think out mechanical explanations for
the small ellipticity in the orbits of the planetary satellites he gave
it up, and noted: “I actually am taking pleasure in chronicling this
small beer (his solitary walks); pure thought proves so thorny to
press.” On April 3d he writes to his father: “I am trying to catch up
with you and grandfather _Sed longo intervallo_ so as to solace my
solitary walks with fixed acquaintances.” Both of these forebears had
been interested in botany. In fact he walked much alone, studying the
trees, shrubs and insects, and he writes: “I can converse with plants
because they don’t talk back, nor demand attention but accept it.”

The time for the eclipse was drawing near, so after going to Florence to
spend a few days more with his sister, he sailed from Genoa on May 16;
trans-shipped at Naples, and going ashore in Sicily and Malta while the
steamer was in port, reached Tripoli on May 24th. Travelling to
out-of-the-way places in the Mediterranean was not a rapid process, and
Tripoli then belonged to Turkey; but he found everything prepared by
Professor Todd in the grounds of the American Consulate, and,
fortunately, when the eclipse occurred four days later the sky was clear
and everything went well. He was amused by the comments of the ignorant.
“The Arabs,” he wrote in his private journal, “the common folk, told
their friends (beforehand) that the Christians lied, and when the affair
came off, that they had no business to know being infidel.” But he was
as always interested in their ways and habits, mousing about the town
with our consul and others, learning about the Turkish troops, and the
Tuaureg camel drivers, inspecting a bakery, a macaroni factory,
threshing and the weekly fair.

On June 3rd they sailed by an Italian steamer for Malta, but he left it
at Tunis to go to the ruins of Carthage, which impressed him greatly;
catching the boat again at Biserta, and at Malta trans-shipping again
for Marseilles, he made his way to Paris. There the exhibition was open,
and among other things he found his exhibit from Flagstaff, “poor waif,
in a corner of the Palais de l’Optique and in another place stood
confronted by four of my own drawings of Mars, unlabelled, unsubscribed.
Felt badly for the poor orphans.” He did not stay long, but went to
England, and after spending a few days at the country house of some
friends he had made on the Riviera, he sailed for home on July 4th.
Shortly before leaving he had received telegrams telling of his father’s
unexpected death under an operation, cutting another link with his
earlier life.

As yet not well enough to resume his work, he hired a farm house at
Chocorua, and settled there on August 3rd for the rest of the summer. He
enjoyed seeing the friends and neighbors who spent their vacations
there; but, like some other men of science incapacitated by illness, he
turned his attention to a field other than his own. As on the Riviera,
this was flowers, butterflies, and especially trees; but he studied them
more systematically, and with fuller notes. In October he gives a list,
covering more than three pages, of the trees and shrubs in the woods,
fields and swamps about him in the order of their abundance. This
interest he kept up in later years at Flagstaff, corresponding with
Professor Charles S. Sargent, the Director of the Arnold Arboretum, and
sending him specimens of rare or unknown varieties, some of which were
named after him. So highly, indeed, did Sargent rate him that after
Percival’s death he wrote a memoir of him in _Rhodora_,[14] which it is
well to transcribe in full:

  “That Percival Lowell took an active interest in trees was probably
  not known to many persons, for he published only one botanical paper
  and he had no botanical associates except in this Arboretum. It is not
  surprising that a man with his active and inquiring mind brought up in
  New England should, when he found himself in Arizona, want to know
  something of the strange plants which grew everywhere about him and
  which were so entirely unlike the plants which he had known as a boy
  in Massachusetts, and later in Japan and Korea. The love of plants,
  too, was in his blood and only needed the opportunity of this new
  field to make itself felt.

  “Percival Lowell’s great great grandfather, John Lowell, was one of
  the original members of the Massachusetts Society for Promoting
  Agriculture and its second President, serving from 1796 until his
  death in 1802. He is less well known for his connection with rural
  affairs than his son John Lowell, spoken of generally in his day as
  “the Norfolk Farmer,” and a generous and successful promoter of
  scientific agriculture and horticulture in Massachusetts, whom Daniel
  Webster called “the uniform friend of all sorts of rural economy.” The
  second John Lowell became a member of the Agricultural Society in 1816
  and served from the time of his election until 1830 as its
  Corresponding Secretary, and as one of the editors of its publication,
  _The Massachusetts Agricultural Repository and Journal_. During these
  years articles by him on agriculture, horticulture and forestry are
  found in almost every number. In volume v. published in 1819 there is
  an important paper by John Lowell on “The Gradual Diminution of the
  Forests of Massachusetts, and the importance of early attention to
  some effectual remedy, with extracts from the work of M. Michaux on
  the Forest Trees of North America.” Volume vii. contains articles from
  his pen on “Some slight notice of the Larch tree (_Pinus Larix_),
  known in various parts of the country under the several names of
  Juniper, Hackmatack, and Larch”; on “Fruit Trees,” signed by the
  Norfolk Gardener, and on “Raising the Oak from the Acorn and the best
  way of doing it.” The last volume of this publication which appeared
  in 1832, when he was seventy-one years old, contains an article by
  John Lowell on “The Extraordinary Destruction of the last Year’s Wood
  in Forest Trees and the probable Causes of it”; and on “Live Hedges
  for New England.” The second John Lowell was active in establishing
  and maintaining the Botanic Garden of Harvard College and was one of
  the original members of the Massachusetts Horticultural Society. To
  the first annual festival of the Horticultural Society held in the
  Exchange Coffee House on State Street, September 19, 1829, he sent
  from his greenhouses in Roxbury Orange-trees covered with flowers and
  fruit and a bunch of grapes weighing three pounds.

  “John Amory Lowell, the son of the second John Lowell and the
  grandfather of Percival Lowell, was deeply interested in botany and in
  1845, thirty years after his graduation from Harvard College, began
  the collection of an herbarium and botanical library with the purpose
  of devoting himself seriously to the study of plants. He had made
  valuable collections and a large botanical library when the financial
  troubles of 1857 forced him to abandon botany and devote himself again
  to business affairs. His most valuable books were given by him to his
  friend Asa Gray and now form an important part of the library of the
  Gray Herbarium. His herbarium and his other botanical books were given
  to the Boston Society of Natural History. John Amory Lowell, like his
  father and grandfather, was a member of the Massachusetts Society for
  Promoting Agriculture. He was succeeded by his son John Lowell, who in
  turn was succeeded by his son, another John Lowell, who of the fifth
  generation in direct descent from its second president is now a
  Trustee of this Society.

  “Percival Lowell’s love of plants certainly came to him naturally. I
  first met him in the Arboretum many years ago examining the collection
  of Asiatic Viburnums in which he was interested at that time, but it
  was not until 1910 that he began to send specimens to the Arboretum,
  including that of an Oak which he had found growing near his
  observatory and which so far as it is possible to judge is an
  undescribed species. Interest in this Oak led him to look for other
  individuals and to extend his botanical explorations. During these he
  visited Oak Creek Canyon, a deep cut with precipitous sides in the
  Colorado plateau which heads about twenty miles south of Flagstaff and
  carries in its bottom a small stream which finally finds its way into
  the Verde northwest and not far from Camp Verde. Lowell appears to
  have been the first botanist who visited the upper part, at least, of
  this canyon where he found a number of interesting plants, notably
  _Platanus Wrightii_ and _Quercus arizonica_, which before his
  explorations were not known to extend into the United States from
  Mexico beyond the canyons of the mountain ranges of southern Arizona
  and New Mexico. In Oak Creek Canyon Lowell found a new Ash-tree
  somewhat intermediate between _Fraxinus quadrangulata_ of the east and
  _F. anomala_ of our southwestern deserts which will bear his name.
  Later Lowell explored Sycamore Canyon which is west of Oak Creek
  Canyon and larger and deeper than Oak Creek Canyon and, like it, cuts
  through the Colorado plateau and finally reaches the Verde near the
  mouth of Oak Creek.

  “Juniperus in several species abound on the Colorado plateau, and
  Lowell became deeply interested in these trees and was preparing to
  write a monograph of our southwestern species. His observations on the
  characters and altitudinal range of the different species, illustrated
  by abundant material, have been of great service to me.

  “Lowell’s only botanical paper, published in the May and June issues
  of the _Bulletin of the American Geographic Society_ in 1909, is
  entitled “The Plateau of the San Francisco Peaks in its Effect on Tree
  Life.” In this paper, which is illustrated by photographs made by the
  author of all the important trees of the region, he discusses the
  altitudinal distribution of these trees, dividing his region into five
  zones which he illustrates by a number of charts showing the
  distribution of vegetation in each. It contains, too, an important and
  interesting discussion of the influence on temperature and therefore
  on tree growth of the larger body of earth in a plateau as compared
  with a mountain peak where, on account of greater exposure, the earth
  cools more rapidly.[15]

  “A bundle of cuttings of what is probably a new species of Willow, to
  obtain which Lowell had made a long and hard journey, with his last
  letter and a photograph of the Willow, came only a few days before the
  telegram announcing his death. Botany therefore occupied his thoughts
  during his last days on earth.

  “The death of Percival Lowell is a severe loss to the Arboretum. He
  understood its purpose and sympathized with its efforts to increase
  knowledge. Few collectors of plants have shown greater enthusiasm or
  more imagination, and living as he did in what he has himself
  described as “one of the most interesting regions of the globe” there
  is every reason to believe that as a botanist Percival Lowell would
  have become famous.”




                              CHAPTER XIII
                          MARS AND ITS CANALS


By the early spring of 1901 Percival was well over his illness, and fit
to return to the Observatory for the oppositions of Mars in that year,
in 1903 and in 1905. Shortly after he came back the services of Mr.
Douglass came to an end, and he was fortunate in obtaining Dr. V. M.
Slipher in 1901 and Mr. C. O. Lampland in the following year—two young
men who were not only invaluable assistants to him, but during his
lifetime, and ever since, have made distinguished contributions to
science. Observing at all hours of the night was exacting work; and to
anyone less enthusiastic, who did not see through the detail to its
object, it might have been monotonous and wearisome. As he wrote
himself, “Patient plodding is the road to results in science, and the
shortest road in the end. Each year out here has seemed to me the best,
which merely means that I hope I learn a little and that there is a vast
deal to learn.” He felt strongly the need of diligence and strict
impartiality in ascertaining the facts, and distinguished it sharply
from the imagination to be used in interpreting them. In describing his
delineation of the canals he says, “Each drawing, it should be
remembered, was as nearly an instantaneous picture of the disk as
possible. It covered only a few minutes of observation, and was made
practically as if the observer had never seen the planet before. In
other words, the man was sunk in the manner. Such mental effacement is
as vital to good observation as mental assertion is afterward to
pregnant reasoning. For a man should be a machine in collecting his
data, a mind in coördinating them. To reverse the process, as is
sometimes done, is not conducive to science.” But through all the
exacting labor of the search he felt keenly the joy of discovery,
comparing himself to the explorers of the Earth, and in the first
chapter of “Mars and its Canals” he tells us of the pleasure of a winter
night spent in the Observatory.

The oppositions in 1901, 1903 and 1905 were not so favorable as those of
1894 and 1906-1907, because Mars was not so near the Earth; the
eccentricities in the orbits of the two planets causing them to pass
each other when Mars was far from the Sun and therefore from the Earth
whose eccentricity is less. Yet they had an advantage in the fact that,
unlike the earlier occasions, the south pole was tipped away from the
Earth, and the north pole was toward it, thus giving a good view of the
northern polar cap, sub-arctic and higher temperate zones, which had not
been visible before. Thus the seasonal changes could be observed in the
opposite hemisphere,—not an inconsiderable gain, because the dark and
light areas, that is, the natural vegetation and the deserts, are not
equally distributed over the planet, for the dark ones occupy a much
larger part of the southern, and the deserts of the northern,
hemisphere. Moreover, the use of a larger lens and better atmosphere had
shown that observations could be carried on profitably for a longer
period before and after the actual opposition; until in 1905 it was
possible to cover what had been left unobserved of the Martian year in
the northern half of Mars.

No sooner was the third of these oppositions past than he wrote another
book on the subject, with the title “Mars and its Canals”; and this in
no sense a supplement to the earlier one, but an entirely new and
independent presentation of the subject, covering the old ground and
much more. He was enabled to do this because the copyright of the
earlier work belonged to him. The later one was published by The
Macmillan Company in December 1906, and dedicated to Schiaparelli. Like
the earlier book, he wrote it by no means for astronomers alone, but for
the interested public; and in the preface he tells why he did so: “To
set forth science in a popular, that is in a generally understandable,
form is as obligatory as to present it in a more technical manner. If
men are to benefit by it, it must be expressed to their comprehension.
To do this should be feasible for him who is master of his subject, and
is both the best test of, and the best training to that post.... Nor is
it so hard to make any well-grasped matter comprehensible to a man of
good general intelligence as is commonly supposed. The whole object of
science is to synthesize, and so simplify; and did we but know the
uttermost of a subject we could make it singularly clear.” At the same
time there was nothing in these writings of the nature of what is
commonly called popularizing science. He expounded his subject in a
strictly scientific way, but avoided unfamiliar technical terms if
possible, and sought to raise his readers or audience to his level of
thought, not to descend to theirs. Such statements for the public were
very often preceded by technical ones in the Bulletins of the
Observatory or elsewhere, and yet it cannot be doubted that the former
tended to alienate some scientific scholars who were slow to admit his
discoveries, and did not sympathize with his method of presenting them,
or perhaps with the attractive style of the man of letters as well as of
exact thought.

Still there are pitfalls in taking the public into one’s confidence; as
he found in December 1900, when a telegram sent by the usual channels to
the astronomical world, that the night before a projection had been
observed on Mars that lasted seventy minutes, was taken by the press to
mean an attempt by Martians to signal to the Earth, and as such was
proclaimed all over America and Europe. The cause of the excitement, as
he explained a year later to the American Philosophical Society in
Philadelphia, was the reflection from a cloud on the horizon of the
planet.

“Mars and its Canals” is frankly a demonstration that the planet is
habitable, and that from what takes place there it must in fact be
inhabited by highly intelligent beings. For that purpose the book is
divided into four parts, entitled: Natural Features; Non-Natural (that
is, artificial) Features; The Canals in Action; and Explanation. His
general thesis, which he was to expound more fully later (and which
although not essential to his argument for life on Mars he connected
therewith) was that all planets go through the same process of
development—varying, however, with their size which determines their
power to retain the gases of their atmosphere—and that one element
therein is the gradual leakage of water through cracks into its interior
as the planet cools. He cites geologists to prove that the oceans
formerly covered much more of the surface of the Earth than they do now;
argues that the desert belts around it are of comparatively recent
geologic origin, as shown by the petrified forest of Arizona; and points
out the similarity in color, as seen from the San Francisco Peaks, of
the forested hills and the painted desert there, to that of the
blue-green and reddish-ochre spaces of Mars as presented by the
telescope. He notes also that to get water in our deserts plants and
animals have sought the higher altitudes, and are able to exist and
multiply in an air less dense and a climate cooler with a shorter warm
season than in their natural habitat, adjusting themselves to these
conditions.

This idea of the lack of water on Mars he derives from observation of
its surface and the changes thereon; for the supply of water is in great
part locked up in the snow or ice of the polar caps during the Martian
winters of the two hemispheres and distributed over its surface as
summer comes on. Therefore he naturally begins his account of the
natural features of the planet by a description of these polar snow
caps, their formation and melting. In doing so he cannot resist a
sarcastic reference to the endless enthusiasm, useless expenditure of
money and labor, and the scientific futility of arctic exploration.

“Polar expeditions exert an extreme attraction on certain minds, perhaps
because they combine the maximum of hardship with the minimum of
headway. Inconclusiveness certainly enables them to be constantly
renewed, without loss either of purpose or prestige. The fact that the
pole has never been trod by man constitutes the lodestone to such
undertakings; and that it continues to defy him only whets his endeavor
the more. Except for the demonstration of the polar drift-current
conceived of and then verified by Nansen, very little has been added by
them to our knowledge of the globe. Nor is there specific reason to
suppose that what they might add would be particularly vital. Nothing
out of the way is suspected of the pole beyond the simple fact of being
so positioned. Yet for their patent inconclusion they continue to be
sent in sublime superiority to failure.

“Martian polar expeditions, as undertaken by the astronomers, are the
antipodes of these pleasingly perilous excursions in three important
regards, which if less appealing to the gallery commend themselves to
the philosopher. They involve comparatively little hardship; they have
accomplished what they set out to do; and the knowledge they have
gleaned has proved fundamental to an understanding of the present
physical condition of the planet.”

Then follows the story of the melting of the polar snows, the darkening
of the blue-green areas by the growth of vegetation due to the flow of
water; and a summary, at the close of [Part I] (Natural Features), of
the reasons for believing that from its atmosphere, temperature, and the
actual, though scanty, supply of water, Mars is capable of supporting
life. In fact the presence of vegetation proves that life of that kind
does exist, in spite of the fact that five-eighths of the surface is
desert; and if plants can live animals might also. But, unlike
vegetation, they could not be readily seen, and save in the case of
intelligent operation on a large scale, their presence could not be
detected. This is the significance of the canals, to which much of the
observation of the last three oppositions was directed.

Close to the limit of vision, and only to be seen at moments when the
atmosphere is steady, the fainter canals are very hard to observe.
Percival describes the experience in this way:

“When a fairly acute eyed observer sets himself to scan the telescopic
disk of the planet in steady air, he will, after noting the dazzling
contour of the white polar cap and the sharp outlines of the blue-green
areas, of a sudden be made aware of a vision as of a thread stretched
somewhere from the blue-green across the orange areas of the disk. Gone
as quickly as it came, he will instinctively doubt his own eyesight, and
credit to illusion what can so unaccountably disappear. Gaze as hard as
he will, no power of his can recall it, when, with the same startling
abruptness, the thing stands before his eyes again. Convinced, after
three or four such showings, that the vision is real, he will still be
left wondering what and where it was. For so short and sudden are its
apparitions that the locating of it is dubiously hard. It is gone each
time before he has got its bearings.

“By persistent watch, however, for the best instants of definition,
backed by the knowledge of what he is to see, he will find its coming
more frequent, more certain and more detailed. At last some particularly
propitious moment will disclose its relation to well known points and
its position be assured. First one such thread and then another will
make its presence evident; and then he will note that each always
appears in place. Repetition _in situ_ will convince him that these
strange visitants are as real as the main markings, and are as permanent
as they.”

Strangely enough fine lines, from the continuity of the impression they
make upon the eye, can be recognized when of a thickness that would be
invisible in the case of a mere dot. To determine how narrow a line on
Mars would be perceptible, experiments were made with a wire of a
certain size, noting the limit of distance at which it could be seen;
and then, from the magnifying power of the telescope, it was found that
a Martian canal would be visible down to about a mile wide. From this
the conclusion was drawn that the canals probably ran from two or three
up to fifteen or twenty miles in width, the minimum being much less than
had been thought at earlier oppositions. The distance apart of the two
branches of double canals he estimated at about seventy-five to one
hundred and eighty miles, save in one case where, if a true instance of
doubling, it is over four hundred. Of the oases, whereof one hundred and
eighty-six had been observed, much the larger part were from
seventy-five to one hundred miles in diameter.

The later oppositions enabled him also to complete the topography of the
planet, showing that the canals were a vast system, running from the
borders of both polar caps, through the dark areas of natural vegetation
where they connected, at obviously convenient points, with a still more
complex network in the ochre, or desert, regions, and thus across the
equator into the corresponding system in the other hemisphere. By this
network the greater part of the canals could receive water alternately
from the melting of the north and south polar caps, or twice yearly, the
Martian year, however, being almost twice as long as our own. But to
perfect his proof that this actually takes place he had to show that the
canals, that is the streaks of vegetation bordering waterways, sprang
into life—thereby becoming visible or darker—in succession as the water
spread from the poles to the tropics; and this he did with his usual
thoroughness at the opposition of 1903.

Since there was then no mechanical means of measuring the variations in
visibility of the canals,—and under the atmospheric conditions at any
place in the world perhaps there never will be,—the record had to be
made by the eye, that is in drawings by the observer as he saw the
canals; and these, as he said, must be numerous, consecutive and
extended in time. The consecutive could not be perfectly carried out
because “as Mars takes about forty minutes longer to turn than the
Earth, such confronting (of the observer) occurs later and later each
night by about forty minutes, until finally it does not occur at all
while Mars is suitably above the horizon; then the feature passes from
sight to remain hidden till the difference of the rotations brings it
round into view again. There are thus times when a given region is
visible, times when it is not, and these succeed each other in from five
to six weeks, and are called presentations. For about a fortnight at
each presentation a region is centrally enough placed to be well seen;
for the rest of the period either ill-placed or on the other side of the
planet.” But with changes as gradual and continuous as those of the
darkening of the canals this did not prove a serious drawback to the
continuity of the record.

There was another element in the problem. The drawing being the estimate
of the observer on the comparative darkness of the markings from time to
time it was of the greatest importance to avoid any variation in
personal estimates, and therefore Percival made all the drawings
himself. From April 6 to May 26 he drew the planet every twenty-four
hours, and although “the rest of the time did not equal this perfection,
no great gap occurred, and one hundred and forty-three nights were
utilized in all.... But even this does not give an idea of the mass of
the data. For by the method employed about 100 drawings were used in the
case of each canal, and as 109 canals were examined this gave 10,900
separate determinations upon which the ultimate result depended.”

For each canal he plotted the curve of its diminishing or increasing
visibility as the season advanced, and this curve he called the
cartouche of the canal. Now combining the cartouches of all the canals
in each zone of latitude, he found that those in the several zones began
to become more distinct—that is the vegetation began to come to life—in
a regular and approximately uniform succession, taking from the northern
arctic down to the equator and past it to the southern sub-tropic about
eighty Martian days. From north latitude 72° to the equator, a distance
of 2,650 miles, took fifty-two of these days, at a speed of fifty-one
miles a day, or 2.1 miles an hour. Now all this is precisely the
opposite of what happens on the Earth, where vegetation in the spring
starts in the part of the temperate zone nearest to the equator, and as
the season advances travels toward the pole; the reason for the
difference being, he says, that what is needed on Earth to make the sap
run is the warmth of the sun, what is needed on Mars is water that comes
from the melting of the polar snows. He points out also that the water
cannot flow through the canals by nature, because on the surface of a
planet in equilibrium gravity would not draw it in any direction toward
or away from the equator. “No natural force propels it, and the
inference is forthright and inevitable that it is artificially helped to
its end. There seems to be no escape from this deduction.” In short,
since water certainly cannot flow by gravity both ways in the same
canal, the inhabitants of Mars have not only dug the canals, but pump
the water through them.

    [Illustration: OBSERVING AND DRAWING THE CANALS OF MARS]

    [Illustration: Drawing]

In recapitulating the reasons for the artificial character of the canals
he shows a most natural annoyance with people who doubted the validity
of his observations; and, in dealing with the evidence to be drawn from
the fact that they run on great circles, that is on the shortest lines
from one point to another, he writes: “For it is the geodetic precision
which the lines exhibit that instantly stamps them to consciousness as
artificial. The inference is so forthright as to be shared by those who
have not seen them to the extent of instant denial of their objectivity.
Drawings of them look too strange to be true. So scepticism imputes to
the draftsman their artificial fashioning, not realizing that by so
doing it bears unconscious witness to their character. For in order to
disprove the deduction it is driven to deny the fact. Now the fact can
look after itself and will be recognized in time.”

This last prophecy was largely verified before these three oppositions
of the planet came to an end. In 1901 photography was tried without
success so far as the canals were concerned. For the stars it had worked
very well, for to quote again: “Far less sensitive than the retina the
dry plate has one advantage over its rival,—its action is cumulative.
The eye sees all it can in the twentieth of a second; after that its
perception, instead of increasing, is dulled, and no amount of
application will result in adding more. With the dry plate it is the
reverse. Time works for, not against it. Within limits, themselves long,
light affects it throughout the period it stands exposed and, roughly
speaking, in direct ratio to the time elapsed. Thus the camera is able
to record stars no human eye has ever caught and to register the
structure of nebulae the eye tries to resolve in vain.

“Where illumination alone is concerned the camera reigns supreme; not so
when it comes to a question of definition. Then by its speed and agility
the eye steps into its place, for the atmosphere is not the void it
could be wished, through which the light-waves shoot at will. Pulsing
athwart it are air-waves of condensation and rarefaction that now
obstruct, now further, the passage of the ray. By the nimbleness of its
action the eye cunningly contrives to catch the good moments among the
poor and carry their message to the brain. The dry plate by its slowness
is impotent to follow. To register anything it must take the bad with
the better to a complete confusion of detail. For the air-waves throw
the image first to one place and then to another, to a blotting of
both.”

There lay the difficulty which Mr. Lampland, then new to the
Observatory, took up in 1903. The photographs, though better, still did
not show the canals. Various adjustments were then made with the
telescope; all manner of plates were tried between the rapid and the
well-defining ones; and finally in 1905 upon the plates canals appeared,
thirty-eight in all and one of them double.[16] On learning of the
success Schiaparelli wrote in wonder to Percival, “I should never have
believed it possible”; and the British Royal Photographic Society
awarded its medal to Mr. Lampland.

With the observations of 1905 ended until the next opposition of the
planet an exploration and a romance of which he wrote:

“To some people it may seem that the very strangeness of Martian life
precludes for it an appeal to human interest. To me this is but a
near-sighted view. The less the life there proves a counterpart of our
earthly state of things, the more it fires fancy and piques inquiry as
to what it be. We all have felt this impulse in our childhood as our
ancestors did before us, when they conjured goblins and spirits from the
vasty void, and if our energy continue we never cease to feel its force
through life. We but exchange, as our years increase, the romance of
fiction for the more thrilling romance of fact. As we grow older we
demand reality, but so this requisite be fulfilled the stranger the
realization the better we are pleased. Perhaps it is the more vivid
imagination of youth that enables us all then to dispense with the
hall-mark of actuality upon our cherished visions; perhaps a deeper
sense of our own oneness with nature as we get on makes us insist upon
getting the real thing. Whatever the reason be, certain it is that with
the years a narration, no matter how enthralling, takes added hold of us
for being true. But though we crave this solid foothold for our
conceptions, we yield on that account no jot or tittle of our interest
for the unexpected.”




                              CHAPTER XIV
                            THE SOLAR SYSTEM


In the intervals of personal observation Percival was often giving
lectures or writing on astronomical subjects for the publications of the
Observatory, and for scientific societies and periodicals. The substance
of most of these found their way into his books, which are summations or
expositions of his conclusions. In December 1902, for example, he gave
six lectures on “The Solar System” at the Massachusetts Institute of
Technology, of which he was a non-resident professor, and they were
published by Houghton, Mifflin & Company. Then in the autumn of 1906 he
gave a course of eight lectures at the Lowell Institute in Boston on
“Mars as the Abode of Life.” These were so crowded that they had to be
repeated, were then printed as six papers in the _Century Magazine_, and
finally re-published by The Macmillan Company under the same title. Two
years later, in the winter of 1909, he gave at the Massachusetts
Institute of Technology, another course of six lectures on “Cosmic
Physics: The Evolution of Worlds,” which were brought out in December by
the same publisher with the latter half of the title. Although their
names are so diverse, and far more is told of Mars in the book whose
title contains its name, they all deal essentially with the same
subject, the evolution of the planets and the development and end of
life upon them. In the Preface to “Mars as the Abode of Life,”—for a
preface, although printed at the beginning, is always written after the
book is finished, and is the author’s last word to the reader, giving
his latest thought as the work is being launched,—he tells us:[17]
“Though dealing specifically with Mars, the theme of the lectures was
that of planetary evolution in general, and this book is thus a
presentation of something which Professor Lowell has long had in mind
and of which his studies of Mars form but a part, the research into the
genesis and development of what we call a world; not the mere
aggregating of matter, but what that aggregation inevitably brings
forth. The subject which links the Nebular Hypothesis to the Darwinian
Theory, bridging the evolutionary gap between the two, he has called
planetology, thus designating the history of the planet’s individual
career. It is in this light that Mars is here regarded: how it came to
be what it is and how it came to differ from the Earth in the process.”

At each opposition, in fact at every opposition during Percival’s life
and long thereafter, Mars was observed at Flagstaff and more detail was
discovered confirming what had been found before. He tells of a slight
change in the estimated tilt in its axis; the fact that the temperature
is warmer than was earlier supposed;[18] and he had found how to
discover the gases by spectroscopic analysis applied according to an
ingenious device of his own known as “Velocity Shift” and much used
thereafter.[19] He tells also of an ingenious and elaborate experiment
with wires, and with lines on a wooden disk, which showed that such
lines can be perceived at a greater distance and therefore of smaller
size than had been supposed, so that the canals might have less width
than had been assumed. It is, however, needless, in describing his
planetary theory, to do more than allude to his evidence of Martian
habitation drawn from the canals, with which the reader is already
familiar. Curiously enough, however, it is interesting to note that on
September 9, 1909, about the time when “The Evolution of Worlds” was
going to press, a strange phenomenon appeared in Mars. Two striking
canals were seen where none had ever been seen before, and the most
conspicuous on that part of the disk. Moreover, they were photographed.
After examining all the maps of canals made at Flagstaff and elsewhere,
Percival discussed them in the Observatory Bulletin No. 45, and
concluded that they must not only be new to us, but new to Mars since
its previous corresponding season of two of our years before: “something
_extra ordinem naturae_.” We may here leave Mars for the time, and turn
to the more extensive study of the evolution of the planetary system.

The desire to rise from a particular case to a more general law was
characteristic of his attitude of mind, constructive and insatiable, and
appears throughout these volumes. It may have been influenced by his
great master Benjamin Peirce, who ever treated any mathematical formula
as a special instance of a more comprehensive one. In such a subject as
the evolution of the planets, especially of life on them, it involved
dipping into many sciences, beyond the physical laws of matter; and he
says in the same preface: “As in all theses, the cogency of the
conclusion hangs upon the validity of each step in the argument. It is
vital that each of these should be based on all that we know of natural
laws and the general principles underlying them.” This did not mean that
all his premises would be universally accepted, but that he found out
all he could about them, convincing himself of their accuracy and of the
validity of the conclusions he draws therefrom. That is all any man of
science can do in a subject larger than his own special, and therefore
limited, field.

But from the time of his resumption of research and the direction of the
observatory in 1901, he was constantly enlarging his own field by the
study of astrophysical subjects, and the methods for their
determination. With this object he was initiating and encouraging
planetary photography. He was constantly writing Dr. V. M. Slipher about
procuring and using spectrographic apparatus and about the results
obtained by him therefrom. By this process the rotations of planets were
determined; and the spectra of the major ones—often reproduced in
astronomical works—have been a puzzle to astrophysicists until their
interpretation in very recent years. He was interested also in nebulae,
especially in spiral ones, taking part in Dr. Slipher’s pioneering
spectrographic work at the observatory, which showed that they were vast
aggregations of stars of different spectral types, moving with great
speed, and far beyond the limits of our universe. For over fifteen years
the observatory was almost alone in this field of research, as well as
in that of globular clusters. It is in fact, the discovery of the rapid
motion of the spiral nebulae away from the solar system that has given
rise to the conception of an expanding universe.

But these discoveries were still largely in the future, and to return to
his books on the planetary system it may be noted that in the two larger
and more popular ones the general planetary theory is expounded in the
text, while the demonstrations of the more complex statements made, and
the mathematical calculations involved, are relegated to a mass of notes
at the end of the volume.

The first of his books on the solar system is the small volume bearing
that title; but since all three of the books here described are several
expositions of the same subject it may be well to treat his views on
each topic in connection with the work in which he deals with it most
fully. Indeed, “The Solar System” is not a general treatise, but rather
a discussion of some striking points, and it is these which one thinks
of in connection therewith.

In considering the origin of the planets he had become much interested
in the meteors, shooting stars, meteoric streams and comets, all or
almost all of which he regarded as parts of the solar system, revolving
about the Sun in elliptic orbits, often so eccentric as to appear
parabolas.[20] The old idea that comets came from outer space and
therefore travelled in hyperbolas can, he points out, be true of few, if
any, of them. “Very few, three or four perhaps, hint at hyperbolas. Not
one is such beyond question.” Many of them are associated with the
meteoric streams with which everyone is familiar at certain seasons of
the year. Indeed seventy-six of these associations were then known, and
comets sometimes break up into such streams.

Now if the comets are travelling in orbits around the Sun they must be
throughout their course within its control, and not within that of some
other star; and therefore he computes how far the Sun’s control extends.
Taking for this purpose our nearest star, α Centauri, a double with a
total mass twice that of the Sun, at a distance of 275,000 astronomical
units, in other words that number of times our distance from the Sun, he
finds that the point at which its attraction and that of the Sun become
equal is 114,000 of these units. This he calls the extent of the Sun’s
domain, certainly an area large enough for any, or almost any, comet
known.[21]

He then turns to some of the planets,—Mercury to show the effect of
tidal action in slowing the rotation of a planet or satellite, and
causing it to turn the same face always to its master.[22] This involved
a highly interesting comparison of Newton’s theory of the tides, long
generally accepted, but not taking enough account of the planet’s
rotation, and that of Sir George Darwin based upon the effect of such
rotation. The general conceptions are even more different than the
results, and the later theory is less concerned with the tides in
oceans, which probably affect only our Earth, than with those of a
planet in a fluid or viscous condition, which may still continue to some
extent after the surface has become partly solidified. He therefore
studies the tide raising force, and the tendency to retardation of
rotation, by the Sun on the planets, and by these on their satellites
while still in a fluid state, tabulating some very striking results.

What he says about Mars is more fully dealt with in his other writings;
and the same is true of Saturn’s rings, except for the reference to the
calculation by Edward Roche of the limit of possible approach by a fluid
satellite to its planet without being disrupted, and for the fact that
this limit in Saturn’s case falls just beyond the outer edge of the
rings. In discussing Saturn’s satellites he brings out a curious analogy
between the order of distribution of these attendants of the three best
known major planets and the order of the planets themselves about the
Sun. In each case the largest of the bodies so revolving is nearly in
the centre of the line, as in the case of Jupiter among the planets; the
second largest the next, or not far, beyond, as in the case of Saturn;
while there is another maximum farther in, for as the Earth is larger
than any planet on either side until Jupiter is reached, so a like order
is found in the satellites of Jupiter, Saturn and Uranus. In other
words, the size in each case rises with increasing distance, falls off,
then rises again to the largest and thence declines. This he believed
cannot be an accidental coincidence, but the result of a law of
development as yet unexplained.

To the ordinary reader the most novel thing he says about Jupiter
relates to its family of comets, for no less than thirty-two of these
bodies have their aphelia, or greatest distance from the Sun, near its
orbit. Moreover, their ascending nodes—that is the place where their
paths if inclined to the plane of the ecliptic pass through it—are close
to its orbit. At some time, therefore, in the vast ages of the past they
must have passed close to the planet, and if so have had their orbits
greatly changed by its attraction. He considers the various effects
Jupiter may have upon a comet, and shows—contrary to the opinion of
Professor H. A. Newton—that any such body moving by the attraction of
the Sun would be going too fast for Jupiter to capture completely. Then
he takes up other effects of deflection. The comet’s speed may be
accelerated and its direction changed even so much as to drive it out of
the solar system; it may be retarded so that its path is contracted and
the aphelion drawn nearer to the planet’s orbit. After calculating the
possible conditions and analyzing the actual orbits of Jupiter’s family,
he comes to the provisional conclusion that these comets have been drawn
from the neighborhood. “It is certain,” he says, “that Jupiter has swept
his neighborhood.... If we consider the comet aphelia of short-period
comets, we shall notice that they are clustered about the path of
Jupiter and the path of Saturn, thinning out to a neutral ground
between, where there are none. Two-thirds of the way from Jupiter’s
orbit to Saturn’s, space is clear of them, the centre of the gap falling
at 8.4 astronomical units from the sun....

“Jupiter is not the only planet that has a comet family. All the large
planets have the like. Saturn has a family of two, Uranus also of two,
Neptune of six; and the spaces between these planets are clear of comet
aphelia; the gaps prove the action.

“Nor does the action, apparently, stop there. Plotting the aphelia of
all the comets that have been observed, we find, as we go out from the
Sun, clusters of them at first, representing, respectively, Jupiter’s,
Saturn’s, Uranus’, and Neptune’s family;[23] but the clusters do not
stop with Neptune. Beyond that planet is a gap, and then at 49 and 50
astronomical units we find two more aphelia, and then nothing again till
we reach 75 units out.

“This can hardly be accident; and if not chance, it means a planet out
there as yet unseen by man, but certain sometime to be detected and
added to the others. Thus not only are comets a part of our system now
recognized, but they act as finger-posts to planets not yet known.”

We shall hear more of this last suggestion hereafter.

In both “Mars as the Abode of Life” and “The Evolution of Worlds,” he
accepts the proposition that our present solar system began with a
collision with some dark body from interstellar space, as had been
suggested by Chamberlin and Moulton a few years before. He points out
that stars which have finished contracting, grown cold and ceased to be
luminous, must exist, and although we cannot see them directly we know
about some of them,—such as the dark companion of Algol, revolving
around it and cutting off two-thirds of its light every three days. Many
dark wanderers there must be, and the _novae_, as he says, are
sometimes, at least, due to a collision with such a body,—not
necessarily an actual impact, but an approach so near that the star is
sprung asunder by the tidal effect. In such a case the opposite sides of
the victim would be driven away from it, and if it was rotating would
form spirals. Now we know that the apparently empty spaces in our solar
system still contain a vast number of little meteoric particles, which
as judged from their velocity do not fall from outer space, but are
members of our system travelling in their own orbits around the sun. As
he puts it, “Could we rise a hundred miles above the Earth’s surface we
should be highly sorry we came, for we should incontinently be killed by
flying brickbats. Instead of masses of a sunlike size we should have to
do with bits of matter on the average smaller than ourselves[24] but
hardly on that account innocuous, as they would strike us with fifteen
hundred times the speed of an express train.” That these meteorites are
moving in the same direction as the Earth he shows by an ingenious
calculation of the proportion that in such a case would be seen at
sunrise and sunset, which accords with the observed facts. Moreover,
their chemical composition shows that they were once parts of a great
hot body from which they have been expelled.

The meteorites that are seen because they become hot and luminous in
traversing our atmosphere, and occasionally fall upon the Earth, are the
remnants of vastly larger numbers formerly circling about the sun, but
which, by collision and attraction, were, as he describes, gathered into
great masses, thus forming the planets. The force of gravity gradually
compacted these fragments closer and closer together, thereby generating
heat which if the body were homogeneous would be in proportion to the
square of its mass. The larger the planet therefore the more heat it
would generate, and owing to the fact that mass is in proportion to the
cube and its radiating surface to the square of the diameter the slower
it would radiate, and thus lose, its heat, so that the larger ones would
be hotter and remain hot longer than the smaller ones.

Some of the planets may once have been white-hot, and luminous of
themselves, some were certainly red-hot, some only darkly warm; all
growing cooler after the amount radiated exceeded the amount generated.
Now by the difference in the heat generated and retained by the larger
and smaller bodies he explains the diverse appearance of those whose
surfaces we know, the Earth, Mars and the Moon. As the surface cools it
forms a crust, but if the interior still remains molten it will continue
to contract, the crust will be too large for it and crinkle, like the
skin of a dried apple; and this will be more true of a large than a
small body. “In like manner is volcanic action relatively increased, and
volcanoes arise, violent and widespread, in proportion; since these are
vents by which the molten matter under pressure within finds exit
abroad.” By a calculation, which agrees with the formula of Laplace, he
finds that the effective internal heat of the Earth might be 10,000
degrees Fahrenheit, enough to account for all the phenomena; and for
Mars only 2,000, which is below the melting point of iron, and would not
cause volcanic action. Now the observations of Mars at Flagstaff show
that there can be no mountains on it more than two or three thousand
feet high, and that the surface is singularly flat.

But here he met a difficulty; for the Moon ought to be flatter still if
it had evolved in the ordinary way, whereas it has enormous volcanic
cones, craters 17,000 feet high, some exceeding 100 miles in diameter,
and a range of mountains rising to nearly 30,000 feet. An explanation he
finds in the analysis of the action of the tides in the Earth-Moon
system by Sir George Darwin, who showed that when traced backward it
“lands us at a time when the Moon might have formed a part of the
Earth’s mass, the two rotating together as a single pear-shaped body in
about five hours.... For in that event the internal heat which the Moon
carried away with it must have been that of the parent body—the amount
the Earth-Moon had been able to amass. Thus the Moon was endowed from
the start of its separate existence with an amount of heat the falling
together of its own mass could never have generated. Thus its great
craters and huge volcanic cones stand explained. It did not originate as
a separate body, but had its birth in a rib of Earth.”[25]

The Flagstaff site having been selected for the purpose of planetary
observation yielded facts less easily detected elsewhere. Mercury, for
instance, is so near the Sun that it could be observed in the dark only
a short time after sunset and before sunrise, an obstacle that gave rise
to errors of fact. Schiaparelli led the way to better results by
observing this planet in broad daylight. Up to that time it had been
supposed to rotate on its axis in about twenty-four hours, and therefore
to have a day and night like those of the Earth, but daylight
observation showed him markings constant on its illuminated face, and
therefore that it turns nearly the same side to the Sun. Before knowing
his conclusions, and therefore independently, the study of Mercury was
taken up at Flagstaff in 1896, and the result was a complete
corroboration of his work. It showed that, as in the case of the Moon
with the Earth, tidal action on the still partially fluid mass had
slowed its rotation until it has little with regard to the central body
around which it revolves. He discovered also other facts about Mercury,
which Schiaparelli had not, that its size, mass and density had not been
accurately measured.

A similar discovery about the period of rotation had been made in the
case of Venus. For more than two centuries astronomers had felt sure
that this period was just under twenty-four hours, figured, indeed, to
the minute. But again it was Schiaparelli who doubted, and once more by
observing the planet at noon; when he noted that the markings on the
disk did not change from day to day, and concluded that the same side
was always pointed at the Sun. At Flagstaff in 1896 his observations
were verified and the inference later confirmed by the spectroscope,
which was, indeed, first brought to the Observatory for that purpose.
Thus Venus, which from its distance from the Sun, its size and density,
is most like the Earth, turns out to be in a totally different
condition, one face baked by unending glare, the other chilled in
interstellar night, and as he puts it: “To Venus the Sun stands
substantially stock-still in the sky,— ... No day, no seasons,
practically no year, diversifies existence or records the flight of
time. Monotony eternalized,—such is Venus’ lot.”[26]

On the movements and physical condition of the Earth it was needless to
dwell, and he passed to the asteroids. He describes how they began to be
discovered at the beginning of the last century by searching for a
planet that would fill a gap in Bode’s law. This, a formula of
arithmetical progression for the distances of the planets from the Sun,
has proved not to be a law at all, especially since the discovery of
Neptune which is much nearer than the formula required; but for nearly a
century it had a strong influence on astronomic thought, and the gap in
the series between Mars and Jupiter was searched for the missing link.
Two were found, then two more, about the middle of the last century
another, and then many, smaller and smaller, until by the time Percival
wrote six hundred were known, and their number seems limitless. Only the
four first found, he remarks, exceed a hundred miles in diameter, the
greater part being hardly over ten or twenty. But here he points out a
notable fact, that they are not evenly distributed throughout this
space; and although massed in a series growing thicker toward its centre
there are many gaps, even close to the centre, where few or no asteroids
are found. Now it is the large size and attraction of Jupiter by which
Percival explains the presence of asteroids with gaps in their ranks,
instead of a planet, in the space between it and Mars; but we shall hear
much more of this subject when we come to his work on Saturn’s rings and
the order in the distribution of the planets.

Jupiter, he tells us, having a mass 318 times that of the Earth, and a
volume 1400 times as large, is much less dense, not much more than
water, in short still fluid; and as it has a tremendous spin, rotating
in less than ten hours, it is more oblate than the Earth; that is, the
diameter at its equator is larger in proportion to that from pole to
pole. The observations at Flagstaff brought out some interesting facts:
first, that the dark belts of cloud that surround it are red, looking as
if the planet within were still molten;[27] second, that the bright
central belt lies exactly upon its equator, without regard to, and hence
independent of, its tilt toward the Sun, and that the belts of cloud on
each side appear at the planet’s morning just as they left it in the
evening. All which shows that Jupiter’s cloud formation is not due to
the Sun, but to its own internal heat, an interpretation of the
phenomena that has a direct bearing on his explanation of the Earth’s
carboniferous age.

Saturn is still less dense, even more oblate; but its most extraordinary
feature is of course the rings. Assumed by the early astronomers to be
solid and continuous, they were later shown to have concentric
intervals, and to be composed of discrete particles. They have usually
been supposed flat, but when the position of the planet was such that
they were seen on edge knots or beads appeared upon them; and in 1907
these were studied critically at Flagstaff, when it was found that the
shadows of the rings on the planet were not uniform, but had dark cores;
these thicker places lying on the outer margin of each ring where it
came to one of the intervals. These phenomena he explained in the same
way as the distribution of the intervals among the asteroids.[28]

About Uranus and Neptune he tells us in this book little that was not
known, and save for their orbits, masses and satellites not much was
known of their condition. But later, in 1911, the spectroscope at
Flagstaff determined the rotation period of Uranus, afterwards precisely
duplicated at the Lick; and later still the spectral bands in the vast
atmosphere of the giant planets were identified as due to methane, or
marsh, gas.[29]




                               CHAPTER XV
                     LATER EVOLUTION OF THE PLANETS


After the planets had been formed through the aggregation of revolving
fragments driven off by the catastrophic collision from the Sun, and
after they had attained their maximum heat in the process, they began,
he says, to go through six stages:

I. The Sun-Stage, when they were white-hot and gave out light. This
could have been true only of the largest ones if any.

II. The Molten Stage, when they were still red-hot, but not enough to
give light, in which are now the four great outer planets.

III. The Solidifying Stage, when a crust formed, and the surface
features of the planet began to assume their character. Here the science
of geology takes its start with the metamorphic rocks, and it is the
dividing line between the inner, smaller, and the outer, larger,
planets.

IV. The Terraqueous Stage, when the surface has become substantially
stable, there are great oceans gradually diminishing in size, and land
gradually increasing. This is the stage of the sedimentary rocks, the
time when the planet passes from its own supply of heat to dependence
upon that of the sun; the stage when life begins, and the one in which
the Earth is now.

V. The Terrestrial Stage, when the oceans have disappeared, and water is
scarce, the one in which Mars is now.

VI. The Dead Stage, where are already the Moon and the satellites of
other planets.

On the question of the origin of life Percival took the mechanistic
view: “Upon the fall of the temperature to the condensing point of
water, occurred another event in the evolution of our planet, the Earth,
and one of great import to us: life arose. For with the formation of
water, protoplasm (the physical basis of all plants and animals) first
became possible, what may be called the life molecule then coming into
existence. By it, starting in a simple, lowly way, and growing in
complexity with time, all vegetable and animal forms have since been
gradually built up. In itself the organic molecule is only a more
intricate chemical combination of the same elements of which the
inorganic substances which preceded it are composed.... There is now no
more reason to doubt that plants grew out of chemical affinity than to
doubt that stones did. Spontaneous generation is as certain as
spontaneous variation, of which it is, in fact, only an expression.”

Life, he believed, began in the oceans soon after they had cooled below
the boiling point, and spread all over them; seaweeds and trilobites
existed in France, Siberia and the Argentine, their nearest relatives
being now confined to the tropics; coral reefs, now found only in warm
equatorial seas, have left their traces within eight degrees of the
pole. This looks as if in paleozoic times the oceans were uniformly
warm. The same record he finds in the plants of the carboniferous age.
Gigantic ferns and other cryptogams grew to an immense size, with vast
rapidity and without stopping, for there are no annual rings of growth,
no signs of the effect of seasons, no flowers, and little or no color.
“Two attributes of the climate this state of things attests. First, it
was warm everywhere with a warmth probably surpassing that of the
tropics of to-day; and, second, the light was tempered to a half-light
known now only under heavy clouds. And both these conditions were
virtually general in locality and continuous in time.” In the later
volume he adds, to corroborate the general darkness, that many of the
earlier trilobites, who lived in shallow water, were blind, while others
had colossal eyes.

Various theories have been advanced to explain the carboniferous age,
which he reviews, showing why they do not account for the facts. His own
is that while the oceans were still hot a vast steaming must have gone
up from them, forming clouds of great density that would keep the sun’s
heat and light out, and the warmth of the Earth in. “In paleozoic times,
then, it was the Earth itself, not the Sun, to which plant and animal
primarily stood beholden for existence. This gives us a most instructive
glimpse into one planetologic process. To the planet’s own internal heat
is due the chief fostering of the beginnings of life upon its
surface.”[30]

But he points out that a time must have come when the Earth, and
especially its seas, had cooled, the envelope of dense cloud had
gradually been pierced, and the sun’s rays let in. Then began the sharp
alternation of day and night, the changes in the seasons and the
diversity of climates, when the palms descended to the tropics, and the
flora and fauna as we know them started to develop. This is the period
when the Sun was dominant, or the Sun-Sustained Stage, the one in which
we live.

Later the Earth went through another experience of which the facts are
well known, but the date and cause have puzzled astronomers and
geologists alike, for it lies in the twilight zone between the regions
they illuminate. It is the Glacial Periods. He discusses the theory of
Croll, once largely accepted but now abandoned, that these periods were
due to a change in the eccentricity of the Earth’s orbit, combined with
a progression of the equinoxes, which so altered the seasons that the
northern hemisphere would have summers hot but too short to melt the
snow and ice accumulated in the long cold winters. In fact Percival had
already reviewed this theory some years before in a paper presented to
the American Philosophic Society (Proc. Vol. XXXIX, No. 164) in which he
showed that the eccentricity and inclination of axis in Mars are very
close to those Croll had attributed to the Earth, and yet a glacial
period does not exist there. In the case of Mars it is the southern
hemisphere that should be glaciated, but in fact, although that pole has
the larger extent of snow in winter this sometimes disappears wholly in
the summer, which is never true at the northern pole. If, indeed, the
amount of ice formed were much larger it would not be melted, so that
the amount of water falling and frozen, and not the eccentricity or
inclination of the axis, would be the cause of an ice age.

But he had another reason for rejecting Croll’s theory, and, indeed, for
disbelieving in a general ice age altogether. It was that the glaciation
does not appear to proceed from the pole, but from various distinct
centres, moving from them in all directions, north as well as south;
while some places, like northern Siberia, that one would expect to be
covered with ice, were not so covered. Nor was the greater cold confined
to the northern hemisphere, for on some mountains at the equator, and
even at the south pole, there was more ice and snow than there is
to-day. His explanation is that certain parts of the Earth’s surface
were for some reason raised higher than they are now; and from the snow
mountains or plateaus so formed the sheets of ice flowed down.

The remainder of the book on “Mars as the Abode of Life”—and it is the
larger part of it—contains the reasons for believing that Mars is
inhabited, the canals artificial, and that the Earth will in like manner
gradually lose its supply of water. But this argument need not be
retraced here, because with it the reader has already been made
familiar. “The Evolution of Worlds” ends with a chapter entitled “Death
of a World”; for to him the whole theory of planetary evolution is a
vast drama, albeit with a tragic close. He describes four ways in which
a planet, and all life thereon, may be destroyed. Three of these are:
the effect of tidal action that would bring the same face always toward
the Sun; the loss of water and atmosphere; and the cooling and final
extinction of the Sun. All these things he cheerfully reminds us are
sure to happen, but at a time enormously distant. The other is a
collision with a star—“That any of the lucent stars, the stars commonly
so called, could collide with the Sun, or come near enough to amount to
the same thing, is demonstrably impossible for aeons of years. But this
is far from the case for a dark star. Such a body might well be within a
hundredth of the distance of the nearest of our known neighbors.... Our
senses could only be cognizant of its proximity by the borrowed light it
reflected from our own Sun.” A collision of this kind might happen at
any time, but he consoles us by saying that “judged by any scale of time
we know, the chance of such occurrence is immeasurably remote.” In an
earlier part of the book he describes what its advent would be:

“We can calculate how much warning we should have of the coming
catastrophe. The Sun with its retinue is speeding through space at the
rate of eleven miles a second toward a point near the bright star Vega.
Since the tramp would probably also be in motion with a speed comparable
with our own, it might hit us coming from any point in space, the
likelihood depending upon the direction and amount of its own speed. So
that at the present moment such a body may be in any part of the sky.
But the chances are greatest if it be coming from the direction toward
which the Sun is travelling, since it would then be approaching us head
on. If it were travelling itself as fast as the Sun, its relative speed
of approach would be twenty-two miles a second.

“The previousness of the warning would depend upon the stranger’s size.
The warning would be long according as the stranger was large. Let us
assume it the mass of the Sun, a most probable supposition. Being dark,
it must have cooled to a solid, and its density therefore be much
greater than the Sun’s, probably something like eight times as great,
giving it a diameter about half his or four hundred and thirty thousand
miles. Its apparent brightness would depend both upon its distance and
upon its intrinsic brightness or albedo, and this last would itself vary
according to its distance from the Sun.... We shall assume, therefore,
that its brilliancy would be only that of the Moon, remembering that the
last stages of its fateful journey would be much more resplendently set
off.

“With these data we can find how long it would be visible before the
collision occurred. As a very small telescopic star it would undoubtedly
escape detection. It is not likely that the stranger would be noticed
simply from its appearance until it had attained the eleventh magnitude.
It would then be one hundred and forty-nine astronomical units from the
Sun or at five times the distance of Neptune. But its detection would
come about not through the eye of the body, but through the eye of the
mind. Long before it could have attracted man’s attention to itself
directly its effects would have betrayed it. Previous, indeed, to its
possible showing in any telescope the behavior of the outer planets of
the system would have revealed its presence. The far plummet of man’s
analysis would have sounded the cause of their disturbance and pointed
out the point from which that disturbance came. Celestial mechanics
would have foretold, as once the discovery of another planet, so now the
end of the world. Unexplained perturbations in the motions of the
planets, the far tremors of its coming, would have spoken to astronomers
as the first heralding of the stranger and of the destruction it was
about to bring. Neptune and Uranus would begin to deviate from their
prescribed paths in a manner not to be accounted for except by the
action of some new force. Their perturbations would resemble those
caused by an unknown exterior planet, but with this difference that the
period of the disturbance would be exactly that of the disturbed
planet’s own period of revolution round the Sun.

“Our exterior sentinels might fail thus to give us warning of the
foreign body because of being at the time in the opposite parts of their
orbits. We should then be first apprised of its coming by Saturn, which
would give us less prefatory notice.

“It would be some twenty-seven years from the time it entered the range
of vision of our present telescopes before it rose to that of the
unarmed eye. It would then have reached forty-nine astronomical units’
distance, or two-thirds as far again as Neptune. From here, however, its
approach would be more rapid. Humanity by this time would have been made
acquainted with its sinister intent from astronomic calculation, and
would watch its slow gaining in conspicuousness with ever growing alarm.
During the next three years it would have ominously increased to a first
magnitude star, and two years and three months more have reached the
distance of Jupiter and surpassed by far in lustre Venus at her
brightest.

“Meanwhile the disturbance occasioned not simply in the outer planets
but in our own Earth would have become very alarming indeed. The seasons
would have been already greatly changed, and the year itself lengthened,
and all these changes fraught with danger to everything upon the Earth’s
face would momentarily grow worse. In one hundred and forty-five days
from the time it passed the distance of Jupiter it would reach the
distance of the Earth. Coming from Vega, it would not hit the Earth or
any of the outer planets, as the Sun’s way is inclined to the planetary
planes by some sixty degrees, but the effects would be none the less
marked for that. Day and night alone of our astronomic relations would
remain. It would be like going mad and yet remaining conscious of the
fact. Instead of following the Sun we should now in whole or part,
according to the direction of its approach, obey the stranger. For
nineteen more days this frightful chaos would continue; as like some
comet glorified a thousand fold the tramp dropped silently upon the Sun.
Toward the close of the nineteenth day the catastrophe would occur, and
almost in merciful deliverance from the already chaotic cataclysm and
the yet greater horror of its contemplation, we should know no
more.”[31]




                              CHAPTER XVI
                               INTERLUDES


Naturally Percival’s observations of Mars, and still more the
conclusions he drew from them, provoked widespread attention among
astronomers, some of whom were convinced, while some withheld judgment
and others were very frankly disbelievers. This did not amaze him, for
he felt that new ideas made their way slowly, and had always done so. He
met objections, argued his case and expected ultimate acceptance of his
views. Perhaps not less naturally the popular interest was also great.
Newspapers as well as periodicals all over America, in England, France,
Germany and other countries, published and discussed his views,
especially, of course, on the existence of intelligent beings on Mars
and their artificial canals upon its surface. Marconi was reported as
saying that within a few years we should be in wireless communication
with them.

Meanwhile his life had been going on at the usual furious pace;
lecturing here and there; writing for scientific journals, mostly, but
not wholly, on planets, satellites etc.; managing his own property and
his father’s estate; keeping in constant touch with his computers in
Boston and his observers at Flagstaff, worrying over the health of one
of them whom he urges to take a vacation and recruit; and also standing
his watch as observer himself. A watch it was, “Jupiter before dinner
and Mars at 4 A.M.” There was also a large correspondence with
astronomers and others who were interested in his work. To one of the
latter he writes on December 14, 1907: “In answer to your note of Dec.
5, which has been forwarded to me here, I beg to say that the best and
final education must always be given by one’s self.”

Although the canals had already been photographed, he was not yet free
from the doubters of the actuality of his observations, for on May 15th
of that year we find him writing to Professor Simon Newcomb—then at the
height of his great reputation who had suggested that the comparative
continuity of the canals was an optical illusion, a long letter giving
the reasons for believing that this could not be so, but that they must
be as observed.[32] The proof of this he was seeking to make more clear,
and in this same year he sent Dr. Slipher, with Professor Todd of
Amherst College, on an expedition to the Andes to take more photographs
of Mars, which appeared in the _Century_ for December.

But it was not all work. The hospitality of the Observatory was kept up;
visiting astronomers and friends lent a gayety to the place. Mr. George
Agassiz, for example, long his friend in many labors, was there for many
months in 1907 and 1909, helping greatly in his observations;[33] the
late Professor Edward S. Morse at sundry times, and Professor Robert W.
Willson in 1909 and 1914. He was also in kindly relations with his
neighbors, who were “courteous enough to ask me to talk, and I am deep
in addresses.” In fact some of them were constantly urging him to stand
for Senator from the State. He was interested also in children, and in
March, 1908, he is sending word to Dr. Slipher about a little girl from
Texas eight years old who is to pass through Flagstaff, and asks
permission to look through his big telescope as she “just loves
astronomy.” He was fond of telling about his meeting a negro tending
chickens to whom he suggested keeping a watch on them the next day
because they would go to roost about eleven o’clock; and they did, for
there was an eclipse of the sun. Some days later he met the negro again,
who expressed astonishment at his knowing in advance that the chickens
would go to roost, and asked if he had known it a week before. Yes, he
had known it then. “Did you know it a month before?” “Yes, I knew it a
month before.” “Did you know it a year before?” “Yes, I knew it a year
before.” “But those chickens weren’t born then!” Had he lived to the
present day he might have discovered a resemblance to some tendencies in
ideas about the present depression.

Nor were his thoughts confined to this country, for in August, 1905, he
writes to a friend: “I go to Japan this autumn, but how and when I have
not yet decided.” His old interest remained, and in April 1908, he
arranged an exhibition in Boston by a Shinto priest of walking over hot
coals and up a ladder of sword blades. “The place,” he says, “was full
and the audience gratified at being asked. While in the distance people
outside the pale stood on carts and boys even to the tops of far off
houses, one perched on the tip of a chimney. Dr. Suga cut himself
slightly but not seriously. He did very well considering, though it was
not possible of course for a poor lone priest to come up to what he
might have done in Japan. The rite was beautifully set forth and the
setting of the whole enclosure worthy the most artistic people in the
world. Policemen kept out the crowd and stared aghast, and altogether it
was a relished function.”

He probably would have been greatly grieved had he been told that he
would never revisit the land where he had spent so much of his earlier
life and thought; but astronomy was now his dominant occupation, and was
constantly presenting new questions to engross his attention and fill
his time. Yet in the years when Mars was not in opposition this did not
prevent, indeed it rather stimulated, visits to Europe, where he saw his
astronomical friends, and lectured on his discoveries; for he was a
member of the National Astronomic Societies of France and Germany, had
received from the former in 1904 the Janssen medal for his researches on
Mars, and in 1907 Mr. Lampland that of the Royal Photographic Society of
Great Britain for the work on the planets. We find him across the ocean
in the summer of 1906, lunching with Sir Robert Ball in Cambridge,
Deslandres and Flammarion in Paris, and “pegging away” there at his
lectures.

Two years later, on June 10, 1908, he married Miss Constance Savage
Keith, and they went abroad at the end of the month. When in London they
met his first cousin, A. Lawrence Rotch, the meteorologist, who like him
had established and directed, at his own expense, an observatory for the
study of his subject; in this case on Blue Hill near Boston. Percival
wanted to photograph measurable lines to see how they appeared in a
camera from the air. So he went up with his cousin in a balloon, and
obtained photographs of the paths in Hyde Park which came out very well.
His wife also went up with them; and, what with his reputation, the
ascent in a balloon and their recent marriage, the event was too much
for a reporter to resist; and there appeared in a newspaper an imaginary
picture of an astronomer and a bride in a wedding dress taking their
honeymoon in the basket of a balloon. They travelled together in
England, Switzerland, Germany and France, and she recalls, when he was
giving a lecture at the Sorbonne, a sudden exclamation from a Frenchman
directly behind her: “Why! He is even clever in French!”

Mrs. Lowell has written an account of the diligence, the enthusiasm, the
hardships of Percival and his colleagues, and the spirit of Flagstaff:

“In October, soon after our return from Europe, I discovered that the
scientist’s motto is—“Time is sacred.” I was to meet him on the train
for Flagstaff leaving the South Station at 2 P.M.; anxious to impress
him with my reputation for being punctual, I boarded the train about ten
minutes before two. Percival came into the car, holding his watch in his
hand, just about two minutes before two. He turned to me: “What time
were you here?” I answered triumphantly: “Oh, I got here about ten
minutes ago.” His reply was: “I consider that just as unpunctual as to
be late. Think how much could have been accomplished in ten minutes!” I
have never forgotten that remark. Percival never wasted minutes.

“Late in the afternoon of the third day, as we were nearing Flagstaff,
through the dusk we could see that there had been a heavy fall of snow,
so deep that when the train stopped our Pullman, being far in the rear,
was where the snow—not having been shovelled—was almost level with the
upper step. The men from the Observatory were there, and their first
words were ‘Seeing Good.’ Percival jumped into the deep snow, and taking
Mr. E. C. Slipher with him, drove to the telescope.

“Astronomers take much for granted so far as the details of domestic
life are concerned, and I made up my mind to be a help and not a
hindrance. Dr. V. M. Slipher’s wife came to the rescue, and under her
supervision things were soon adjusted even to a hot supper and
preparation for breakfast the next morning. She was, and always is, a
wonder. Though the wife be not an astronomer a happy asset is it if she
can appreciate her husband’s work, his sacrifices and self-denials. Many
times have I seen their frost-bitten ears and thumbs; hungry and tired
men, but never complaining—patience personified. They are slaves to the
laws that rule the celestial.

“The house we lived in on Mars Hill was a long rambling one, both roof
and sides shingled. Inside all but two rooms were finished, and
partitioned. Two were papered; one of them I papered because no paper
hanger happened to be in town. Occasionally Percival would come in to
see how the work was progressing, and help by steadying the ladder or
stirring the paste. The sitting room—or den, as it was referred to more
often—was lined with half logs from which the bark had not been
stripped. In the ceiling were logs used as beams. During the evening,
when all was quiet, one might hear insects busily working out some
scheme of their own. Open spaces were beamed and, as the logs did not
exactly fit, through the spaces trade-rats would descend from the attic.

“To love nature, and the one for whom one works, it matters not where
one is; that is what one realizes when on Mars Hill. One learns to go
without things. They seem of such minor importance to that for which the
men are seeking; one gets ashamed of oneself to think otherwise. Each
man moves with a definite purpose, indefatigable workers, no thought of
themselves when skies are clear, always watching, cold or torrid heat
makes no difference, work goes on just the same.

“I became deeply impressed with the necessity of obedience to laws. I
said once to Percival that I had been asked if it were true that he was
an atheist, a non-believer. His answer was that he believed in keeping
the laws; what chaos would happen if they were not. Often he would quote
passages from the Bible—[Genesis I, 14-20]. The laws made on Mount
Sinai, he said, are still the same laws to obey. To live in the
atmosphere of such men accomplishing great things, deprived of many
material comforts, makes one feel humble and spurs one on to ‘Help and
not to hinder.’

“Servants we often had to do without. They would come out with us, and
then after a few days, learning of the nearness to the Pacific coast,
the lure of California would bring from them some lame excuse to leave,
at once! To obtain others, when none were to be had in the town, I would
have to go to Los Angeles. Finally, after several had left, I persuaded
Percival to let me try to do the cooking; and later he would refer to
that time as happy peaceful days. With the help of the kind wives, Mrs.
Slipher and Mrs. Lampland, I learned much, how to make bread and
soup,—two very essential articles in our household,—and to get up
camping outfits and quick meals for unexpected guests.

“Lonesome, monotonous—never. Distant as Mars Hill may be from large
cities, something of interest was happening continually. The State
Normal School of Arizona is in the town, and on certain nights classes
of students were brought up the hill to look through the telescope.
Flagstaff is on the main line of the Santa Fe. There were three incoming
trains from the East each day, and as many from the West, and many
people stop off there to visit the different points of interest, the
Lowell Observatory being one.

“In August, 1910, a group of astronomers, representing the International
Union for Coöperation in Solar Research, debarked from the train, on
their way to Pasadena; Professor Herbert H. Turner from England among
them. He it was who many years later suggested for Percival’s ‘Planet X’
the name Pluto. The group, of about thirty, arrived by the first morning
train and stayed at the Observatory until the last train left at night.
The one thing that I was successful in getting enough of for lunch and
dinner was watermelon. It proved a happy hit; for a year or two
afterward, when telling how much they enjoyed their visit, the
watermelons were spoken of as being such a treat. It was a hot day and
the melons were cold; probably that explained their enthusiasm.

“One Christmas we invited all the children of Flagstaff to come to the
Observatory for a Christmas tree and supper. Percival dressed as Santa
Claus and spoke to them down the chimney; then he came down into the
Library where they were gathered about the tree, and gave a present and
candy to every child. That was twenty-seven years ago. When I was in
Flagstaff this spring, the little child I had held in my lap while
Percival read ‘The Night Before Christmas’ came to speak to me and told
me never would she forget that Christmas, and that her two little
children repeatedly asked her to tell them the story of that Christmas
and all that happened at the Santa Claus party on Mars Hill.”

In a recent letter to Mrs. Lowell, Dr. Lampland also gives a glimpse
into Percival’s life at Flagstaff; and though written to refresh her
recollections she preferred to insert it as it stands.

“Fresh in memory and pleasant to recall are your many visits to
Flagstaff and your activities at the Observatory, where you were
designing and supervising architect, carrying through the additions to
the director’s residence, the garage, and the new administration
building. And I also remember your valued help to us in connection with
the house in which we live and your telegram ‘Mr. Lowell gives
benediction and sanction to plans. Proceed.’”

He then goes on to tell of Percival’s friends from both West and East,
and continues:

“You remember he was an enthusiastic gardener and always had a garden
here at the Observatory. He had great success with many flowers and I
recall especially fine displays of hollyhocks, zinnias, and a
considerable variety of bulbs. Gourds, squashes and pumpkins were also
great favorites. You will remember one year the especially fine
collection of gourds and that bumper crop of huge pumpkins, many prize
specimens being sugar fed. At times Dr. Lowell could be seen in the
short intervals he took for outdoor recreation, busy with his little
camel’s hair brush pollenizing some of the flowers. And perhaps you will
remember the little record book lying on the back veranda containing his
observations of the daily growth of the diameter of the gourds, all
measured carefully with little calipers. Then the frequent, almost
daily, walks on the mesa. Certainly he knew all the surrounding country
better than anyone here. He would refer to the different places such as
Wolf Canyon, Amphitheatre Canyon, Indian Paint Brush Ridge, Holly
Ravine, Mullein Patch, etc. In these walks he seemed to be constantly
observing something new and of course trees, flowers, and wild life
always interested him. Trees were an endless source of interest to him
and he took many trips to more distant localities for these studies.
Cedars or junipers seemed to be favorite subjects for study, though
other varieties or kinds were not overlooked. An oak and an ash were
named after him, new species that were discovered on the Observatory
mesa and in Sycamore Canyon.

“At every season of the year he always found something in wild life to
fascinate him, and you will remember his observations and notes of
butterflies, birds, squirrels, rabbits, coyotes, deer and other
inhabitants of the mesa. These friends must never be disturbed or
harmed. But it was permissible to hunt with a camera! And he himself
delighted with his kodak, photographing footprints, etc., and often
attempting to get exposures of the creatures themselves. The Observatory
grounds were a sanctuary for wild life.

“For many of us an interesting side of eminent personages is to know
something about their activities, such for example as reading, outside
of their professional occupations. In Dr. Lowell’s case you should find
ample opportunity to treat a subject that will not admit of monotony. It
would seem that practically every field of knowledge interested him. For
the lighter reading as a relaxing and restful diversion you will
remember the full bookshelves of detective stories, travel, exploration,
etc. Accounts of adventure and discoveries, if well written, were
welcome to his list of miscellaneous reading. The Latin classics were
always near at hand, and widely and well had he read them, and much were
they prized as friends in his later life.

“As you know, it is not easy for the observing astronomer to lead a
strictly regular life in that the hours at the telescope often make it
necessary to use, for the much needed rest, part of the daily hours
usually given to work. His intense occupation with his research
problems, however, was broken with great regularity for short intervals
before lunch and dinner. These times of recreation were given to walks
on the mesa or work in the garden. When night came, if he was not
occupied at the telescope, he was generally to be found in his den. It
was not always possible for him to lay aside his research problems at
this time of the day, but he did have some wholesome views on the
necessity of recreation and a necessary amount of leisure to prevent a
person from falling into the habit of the ‘grind.’ To those who came to
his den the picture of some difficult technical work near his chair,
such as Tisserand’s _Mechanique Celeste_ will be recalled, though he
might at the time be occupied with reading of a lighter character. And
occasionally during the evening he might be seen consulting certain
difficult parts upon which he was pondering....

“The famous outing to the White Mountains was often the subject of much
amusement at the dinner parties when Dr. Lowell and Judge Doe were both
there. In later years that famous expedition seemed to be an
inexhaustible source of fun—the voracious mosquitoes, the discomforts of
a camp and beds under water, atrocious coffee, and so on!!

“And this reminds me of many dinner parties on Dr. Lowell’s and Judge
Doe’s birthdays. These were jolly gatherings, and the brilliant repartee
passing between Dr. Lowell and the Judge was a great delight to those
who were present.

“Many things about the place often remind me of the intensely busy days
before Dr. Lowell passed away. There were several excursions for his
tree studies, to Sycamore Canyon, an arduous trip, and to other
localities near Flagstaff for further studies of different species of
junipers in their native habitat. The specimens were carefully sorted
and packed for Professor Sargent of the Arnold Arboretum. Then I
remember helping him plant many bulbs on the last two days before he was
fatally stricken. The squills he planted at that time in the little bed
under the oak tree near the entrance of the B. M. return every
spring.”[34]




                              CHAPTER XVII
                   THE EFFECT OF COMMENSURATE PERIODS
                    The Asteroids and Saturn’s Rings


Ever inquiring, ever fertile, his mind turned to seek the explanation of
divers astronomical phenomena. In 1912, for example, under the title
“Precession and the Pyramids,” we find him discussing in the _Popular
Science Monthly_ the pyramid of Cheops as an astronomical observatory,
with its relation to the position of the star then nearest to the North
Pole, its lines of light and shadow, in a great gallery constructed with
the object of recording the exact changes in the seasons.

But leaving aside these lesser interests, and the unbroken systematic
observation of the planets, his attention in the later years of his life
was chiefly occupied by two subjects, not unconnected, but which may be
described separately. They are, first, the influence over each other’s
position and orbits of two bodies, both revolving about a far larger
one; and, second, the search for an outer planet beyond the path of
Neptune. Each of these studies involved the use of mathematics with
expanding series of equations which no one had better attempt to follow
unless he is fresh and fluent in such forms of expression. For accurate
and quantitative results they are absolutely essential, but an
impression of what he was striving to do may be given without them.

Two bodies revolving about a common centre at different distances, and
therefore different rates of revolution, will sometimes be on the same
side of the central body, and thus nearer together; sometimes on
opposite sides, when they will be much farther apart. Now it is clear
that the attraction of gravity, being inversely as the square of the
distance, will be greatest when they are nearest together; and if this
happens at the same point in their orbits every time they approach each
other the effect will be cumulative, and in the aggregate much larger
than if they approach at different parts of their orbits and hence pull
each other sometimes in one direction and sometimes in another. To use a
homely, and not altogether apt, illustration: If a man, starting from
his front door, walk every day across his front lawn in the same track
he will soon make a beaten path and wear the grass away. If, instead, he
walk by this path only every other day and on the alternate days by
another, he will make two paths, neither of which will be so much worn.
If he walk by three tracks in succession the paths will be still less
worn; and if he never walk twice in the same place the effect on the
grass will be imperceptible.

Now, if the period taken by the outer body to complete its orbit be just
twice as long as that taken by the inner, they will not come close
together again until the outer one has gone round once to the inner
one’s twice, and they will always approach at the same point in their
orbits. Hence the effects on each other will be greatest. If the outer
one take just two turns while the inner takes three they will approach
again only at the same point, but less frequently; so that the pull will
be always the same, but repeated less often. This will be clearly true
whenever the rates of the revolution differ by unity: _e.g._, 1 to 2, 2
to 3, 3 to 4, 4 to 5, etc.

Take another case where the periods differ by two; for example, where
the inner body revolves about the central one three times while the
outer one does so once; in that case the inner one will catch up with
the outer when the latter has completed half a revolution and the inner
one and a half; and again when the outer has completed one whole
revolution and the inner three. In this case there will be two strong
pulls on opposite sides of the orbits, and, as these pulls are not the
same, the total effect will be less than if there were only one pull in
one direction. This is true whenever the periods of revolution differ by
two, _e.g._, 1 to 3, 3 to 5, 5 to 7. If the periods differ by three the
two bodies will approach three times,—once at the starting point, then
one third way round, and again two thirds way round, before they reach
the starting point; three different pulls clearly less effective.

In cases like these, where the two bodies approach in only a limited
number of places in their orbits the two periods of revolution are
called commensurate, because their ratio is expressed by a simple
fraction. The effect is greater as the number of such places in the
orbit is less, and as the number of revolutions before they approach is
less. But it is clearly greater than when the two bodies approach always
at different places in their orbits, never again where they have done so
before. This is when the two periods are incommensurate, so that their
ratio cannot be expressed by any vulgar fraction. One other point must
be noticed. The commensurate orbit, and hence the distance from the Sun,
and the period of revolution, of the smaller and therefore most affected
body, may not be far from a distance where the orbits would be
incommensurate. To take the most completely incommensurate ratio known
to science, that of the diameter of a circle to the circumference, which
has been carried out to seven hundred decimal places without repetition
of the figures. This is expressed by the decimal fraction .314159 etc.
and yet this differs from the simple commensurate 1/3 or .333333 etc. by
only about five per cent.; so that a smaller body may have to be pulled
by the larger, only a very short way before it reaches a point where it
will be seriously affected no more.

The idea that commensurateness affects the mutual attraction of bodies,
and hence the perturbations in their orbits, especially of the smaller
one, was not new; but Percival carried it farther, and to a greater
degree of accuracy, by observation, by mathematics and in its
applications. The most obvious example of its effects lay in the
influence of Jupiter upon the distribution of the asteroids, that almost
innumerable collection of small bodies revolving about the Sun between
the orbits of Jupiter and Mars, of which some six hundred had been
discovered. These are so small, compared with Jupiter, that, not only
individually but in the aggregate, their influence upon it may be
disregarded, and only its effect upon them be considered. In its
immediate neighborhood the commensurate periods, Percival points out,
come so close together (100 to 101, 99 to 100, etc.) that although
occasions of approach would be infrequent they would be enough in time
to disturb any bodies so near, until the planet had cleared out
everything in its vicinity that did not, by revolving around it, become
its own satellite.

Farther off Jupiter’s commensurate zones are less frequent, but where
they occur the fragments revolving about the Sun would be so perturbed
by the attraction of the planet as to be displaced, mainly, as Percival
points out, to the sunward side. This has made gaps bare of such
fragments, and between them incommensurate spaces where they could move
freely in their solar orbits. Here they might have gathered in a nucleus
and, collecting other fragments to it, form a small planet, were it not
that the gaps were frequent enough to prevent nuclei of sufficient size
arising anywhere. Thus the asteroids remained a host of little bodies
revolving about the Sun, with gaps in their ranks—as he puts it “embryos
of planets destined never to be born.”

The upper diagram in the plate opposite page 166 shows the distribution
and relative densities of the asteroids, with the gaps at the
commensurate points. The plate is taken from his “Memoir on Saturn’s
Rings,”[35] and brings us to another study of commensurate periods with
quite a different set of bodies obeying the same law. Indeed, among the
planets observed at Flagstaff not the least interesting was Saturn, and
its greatest peculiarity was its rings.

In Bulletin No. 32 of the Observatory (Nov. 24, 1907) Percival had
written: “Laplace first showed that the rings could not be, as they
appear, wide solid rings inasmuch as the strains due to the differing
attraction of Saturn for the several parts must disrupt them. Peirce
then proved that even a series of very narrow solid rings could not
subsist and that the rings must be fluid. Finally Clerk-Maxwell showed
that even this was not enough and that the rings to be stable must be
made up of discrete particles, a swarm of meteorites in fact. But, if my
memory serves me right, Clerk-Maxwell himself pointed out that even such
a system could not eternally endure but was bound eventually to be
forced both out and in, a part falling upon the surface of the planet, a
part going to form a satellite farther away.

“Even before this Edward Roche in 1848 had shown that the rings must be
composed of discrete particles, mere dust and ashes. He drew this
conclusion from his investigations on the minimum distance at which a
fluid satellite could revolve around its primary without being disrupted
by tidal strains.

“The dissolution which Clerk-Maxwell foresaw can easily be proved to be
inevitable if the particles composing the swarm are not at considerable
distances from one another, which is certainly not the case with the
rings as witnessed by the light they send us even allowing for their
comminuted form. For a swarm of particles thus revolving round a primary
are in stable equilibrium _only in the absence of collisions_. Now in a
crowded company collisions due either to the mutual pulls of the
particles or to the perturbations of the satellites must occur. At each
collision although the moment of momentum remains the same, energy is
lost unless the bodies be perfectly elastic, a condition not found in
nature, the lost energy being converted into heat. In consequence some
particles will be forced in toward the planet while others are driven
out and eventually the ring system disappears.

“Now the interest of the observations at Flagstaff consists in their
showing us this disintegration in process of taking place and
furthermore in a way that brings before us an interesting case of
celestial mechanics.”

He examines the rings mathematically, as the result of perturbations
caused by the two nearest of the planet’s satellites, Mimas and
Enceladus.

The effect is the same that occurs in the case of Jupiter and the
asteroids, Saturn taking the place of the Sun, his satellites that of
Jupiter, and the rings that of the asteroids. In spite of repetition it
may be well to state in his own words the principle of commensurate
periods and its application to the rings:[36]

“The same thing can be seen geometrically by considering that the two
bodies have their greatest perturbing effect on one another when in
conjunction and that if the periods of the two be commensurate they will
come to conjunction over and over in these same points of the orbit and
thus the disturbance produced by one on the other be cumulative. If the
periods are not commensurate the conjunctions will take place in ever
shifting positions and a certain compensation be effected in the
outstanding results. In proportion as the ratio of periods is simple
will the perturbation be potent. Thus with the ratio 1:2 the two bodies
will approach closest only at one spot and always there until the
perturbations induced themselves destroy the commensurability of period.
With 1:3 they will approach at two different spots recurrently; with 1:4
at three, and so on....

“We see, then, that perturbations, which in this case will result in
collisions, must be greatest on those particles which have periods
commensurate with those of the satellites. But inasmuch as there are
many particles in any cross-section of the ring there must be a
component of motion in any collision tending to throw the colliding
particles out of the plane of the ring, either above or below it.

“Considering, now, those points where commensurability exists between
the periods of particle and satellite we find these in the order of
their potency:

  With Mimas,           1:2
                        1:3
                        1:4
  With Enceladus,       1:3

2:3 of Mimas and 1:2; 2:3 of Enceladus falling outside the ring system.
1:2 of Mimas and 1:3 of Enceladus fall in Cassini’s division, which
separates ring A from ring B.... 1:3 of Mimas’ period falls at the
boundary of ring B and ring C at 1:50 radii of Saturn from the centre.”

In the following years this supposition was reinforced by the discovery
of six new divisions in the rings. Three of them were in ring A and
three in ring B, two of them in each case seen by Percival for the first
time. This led to very careful measurements of Saturn’s ball and rings
in 1913-14 and again in 1915; recorded in Bulletins 66 and 68 of the
Observatory. Careful allowance was made for irradiation, and the results
checked by having two sets of measurements, one made by Percival, the
other by Mr. E. C. Slipher. The observations were, of course, made when
the rings were so tilted to the Earth as to show very widely, the tilt
on March 21, 1915, showing them at their widest for fifteen years.

But unfortunately, as it seemed, the divisions in the rings did not come
quite where the commensurate ratios with the two nearest satellites
should place them. They came in the right order and nearly where they
ought to be, but always a little farther from Saturn. It occurred to
Percival that this might be due to an error in the calculation of the
motion of the rings, that if the attraction of Saturn were slightly more
than had been supposed the revolutions of all parts of the rings would
be slightly faster, and the places in them where the periods would be
commensurate with the satellites would be slightly farther out, that is
where the divisions actually occur. Everyone knows that the earth is not
a perfect sphere but slightly elliptical, or oblate, contracted from
pole to pole and enlarged at the equator; and the same is even more true
of Saturn on account of its greater velocity of rotation. Now its
attraction on bodies as near it as the rings, and to a less extent on
its satellites, is a little greater than it would be if it were a
perfect uniform sphere; and it would be greater still if it were not
uniform throughout, but composed of layers increasing in density, in
rapidity of rotation, and hence in oblateness, toward the centre.
Percival made, therefore, a highly intricate calculation on what the
attraction of such a body would be (“Observatory Memoir on Saturn’s
Rings,” Sept. 7, 1915), and found that it accounted almost exactly for
the discrepancy between the points of computed commensurateness and the
observed divisions in the rings. Such a constitution of Saturn is by no
means improbable in view of its still fluid condition and the process of
contraction that it is undergoing. He found it noteworthy that a study
of the perturbations of the rings by the satellites should bring to
light the invisible constitution of the planet itself:

“Small discrepancies are often big with meaning. Just as the more
accurate determination of the nitrogen content of the air led Sir
William Ramsay to the discovery of argon; so these residuals between the
computed and the observed features of _Saturn’s_ rings seem to lead to a
new conception of _Saturn’s_ internal constitution. That the mere
position of his rings should reveal something within him which we cannot
see may well appear as singular as it is significant.” (p. 5); and he
concludes: (pp. 20-22).

“All this indicates that _Saturn_ has not yet settled down to a uniform
rotation. Not only in the spots we see is the rate different for
different spots but from this investigation it would appear that the
speed of its spin increases as one sinks from surface to centre.[37]

“The subject of this memoir is of course two-fold: first, the observed
discrepancy, and second, the theory to account for it. The former
demands explanation and the latter seems the only way to satisfy it.
From the positions of the divisions in its rings we are thus led to
believe that _Saturn_ is actually rotating in layers with different
velocities, the inside ones turning the faster. If these layers were two
only, or substantially two, this would result in _Saturn’s_ being
composed of a very oblate kernel surrounded by a less oblate husk of
cloud.”

    [Illustration: ASTEROIDS and SATURN’S RINGS]

                               MAJOR AXES
    DISTANCES AT WHICH PERIODS ARE COMMENSURATE WITH THAT OF JUPITER
                1/4 1/3 3/8 2/5 3/7 4/9 5/11 1/2 3/5 2/3

  DISTANCES AT WHICH PERIODS ARE COMMENSURATE WITH THOSE OF MIMAS AND
                               ENCELADUS
         1/4 1/3 1/4E. 3/8 2/5 3/7 4/9 5/11 1/2 2/5E. 3/5 3/7E.

The divisions so made in Saturn’s rings by its satellites may be seen in
the lower of the two diagrams opposite; the three fractions followed by
an E indicating the divisions caused by Enceladus, the rest those caused
by Mimas. The upper diagram represents, as already remarked, the similar
effects by Jupiter on the asteroids. A slight inspection shows their
coincidence.




                             CHAPTER XVIIII
                       THE ORIGIN OF THE PLANETS


In a paper presented to the American Academy in April, 1913, and printed
in their Memoirs[38] Percival explained the “Origin of the Planets” by
the same principle of commensurate periods. In addition to what has
already been said about the places where these periods occur coming
closer and closer together as an object nears the planet, so that it is
enabled to draw neighboring small bodies into itself, he points out that
in attracting any object outside of its own orbit a planet is acting
from the same side as the Sun thereby increasing the Sun’s attraction,
accelerating the motion of the particle and making it come sunward.
Whereas on a particle inside its orbit the planet is acting against the
Sun, thereby diminishing its attraction, slowing the motion of the
particle and causing it to move outward. “Thus a body already formed
tends to draw surrounding matter to itself by making that matter’s mean
motion nearly synchronous with its own.” These two facts, the
close—almost continuous—commensurate points, and the effects on the
speed of revolution of particles outside and inside its own orbit,
assist a nucleus once formed to sweep clear the space so far as its
influence is predominant, drawing all matter there to itself, until it
has attained its full size. “Any difference of density in a revolving
nebula is thus a starting point for accumulation. So soon as two or
three particles have gathered together they tend by increased mass to
annex their neighbors. An embryo planet is thus formed. By the same
principle it grows crescendo through an ever increasing sphere of
influence until the commensurate points are too far apart to bridge by
their oscillation the space between them.”

So much for the process of forming a planet; but what he was seeking was
why the planets formed just where they did. For this purpose he worked
out intricate mathematical formulae, based on those already known but
more fully and exactly developed. These it is not necessary to follow,
for the results may be set forth,—so far as possible in his own words.
“Beyond a certain distance from the planet the commensurate-period
swings no longer suffice to bridge the intervening space and the
planet’s annexing power stops. This happens somewhat before a certain
place is reached where three potent periodic ratios succeed each
other—1:2, 2:5, 1:3. For here the distances between the periodic points
is greatly increased....

“At this distance a new action sets in. Though the character of its
occasioning be the same it produces a very different outcome. The
greater swing of the particles at these commensurate points together
with a temporary massing of some of them near it conduces to collisions
and near approaches between them which must end in a certain permanent
combining there. A nucleus of consolidation is thus formed. This
attracts other particles to it, gaining force by what it feeds on, until
out of the once diffused mass a new planet comes into being which in its
turn gathers to itself the matter about it.

“A new planet tends to collect here: because the annexing power of the
old has here ceased while at the same time the scattered constituents to
compose it are here aided to combine by the very potent commensurability
perturbations of its already formed neighbor.

“So soon as it has come into being another begins to be beyond it,
called up in the same manner. It could not do so earlier because the
most important _deus ex machina_ in the matter, the perturbation of its
predecessor, was lacking.

“So the process goes on, each planet acting as a sort of elder sister in
bringing up the next.

“That such must have been the genesis of the several planets is evident
when we consider that had each arisen of itself out of surrounding
matter there would have been in celestial mechanics nothing to prevent
their being situated in almost any relative positions other than the
peculiar one in which they actually stand....

“It will be noticed that the several planets are not quite at the
commensurate points. They are in fact all just inside them.... Suppose
now a particle or planet close to the commensurable point inside it. The
mean motion in consequence of the above perturbation will be permanently
increased, and therefore the major axis be permanently decreased. In
other words, the particle or planet will be pushed sunward. If it be
still where” the effect of the commensurateness is still felt “it will
suffer another push, and so on until it has reached a place where the
perturbation is no longer sensible.” He then goes on to show from his
formulae that if the particle were just within the outer edge of the
place where the perturbation began to be effective it would also be
pushed sunward, and so across the commensurable point until it joined
those previously displaced.

“We thus reach from theory two conclusions:

“1. All the planets were originally forced to form where the important
and closely lying commensurable points 1:2, 2:5, or 1:3, and in one case
3:5, existed with their neighbors; which of these points it was being
determined by the perturbations themselves.

“2. Each planet was at the same time pushed somewhat sunward by
perturbation.”

He then calculates the mutual perturbations of the major axes of the
outer planets taken in pairs and of Venus and the Earth.

“From them we note that:

“1. The inner planet is _caeteris paribus_ more potent than the outer.

“2. The greater the mass of the disturber and, in certain cases, the
greater the excentricity of either the disturber or the disturbed the
greater the effect.”

As he points out, the effect of each component of the pair is masked by
the simultaneous action of the other, and refers to the case of Jupiter
and the asteroids, where the effect they have upon it is imperceptible,
and we can see its effect upon them clearly.

Thus he shows that a new planet would naturally arise near to a point
where its orbit would be commensurate with that of the older one next to
it. But the particular commensurate fraction in each case is not so
certain. In general it would depend upon the ratio of the two pulls to
each other, for if “the action of the more potent planet greatly exceeds
the other’s it sweeps to itself particles farther away than would
otherwise be possible”; if it does not so greatly exceed it would not
sweep them from so far and hence allow the other planet to form nearer.
Now of the four commensurate ratios mentioned, near which a planet may
form its neighbor, that of 3:5 means that the two planets are relatively
nearest together, for the inner one makes only five revolutions while
the outer makes three, that is the inner one revolves around the Sun
less than twice as fast as the outer one. The ratio 1:2 means that the
inner one revolves just twice as fast as the outer; while 2:5 means that
it revolves twice and a half as fast, and 1:3 that it does so three
times as fast. Thus the nearer equal the pulls of any pair of forming
planets the larger the fraction and the nearer the relative distance
between them. Relative, mind, for as we go away from the Sun all the
dimensions increase and the actual distances between the planets among
the rest.

Venus is smaller than the Earth, but her interior position gives her an
advantage more than enough to make up for this, with the result that the
pulls of the two are more nearly equal than those of any other pair, the
commensurate ratio being 3:5. The next nearest equality of pull is
between Uranus and Neptune, where the commensurate ratio is 1:2; the
next between Jupiter and Saturn, and Venus and Mercury, where it is 2:5;
the least equality being between Saturn and Uranus, where it is only
1:3. Mars seems exceptional for, as Percival says, from the mutual pulls
we should expect its ratio with the Earth to be 1:3 instead of 1:2 as it
is, and he suggests as the explanation, “the continued action of the
gigantic Jupiter in this territory, or it may be that a second origin of
condensation started with the Earth while Jupiter fashioned the outer
planets.”

He brings the Memoir to an end with the following summary:

“From the foregoing some interesting deductions are possible:

“1. The planets grew out of scattered material. For had they arisen from
already more or less complete nuclei these could not have borne to one
another the general comensurate relation of mean motions existent
to-day.

“2. Each brought the next one into being by the perturbation it induced
in the scattered material at a definite distance from it.

“3. Jupiter was the starting point, certainly as regards the major
planets; and is the only one among them that could have had a nucleus at
the start, though that, too, may equally have been lacking.

“4. After this was formed Saturn, then Uranus, and then Neptune.” (This
he shows from the densities of these planets.)

“5. The asteroids point unmistakably to such a genesis, missed in the
making.

“6. The inner planets betray _inter se_ the action of the same law, and
dovetail into the major ones through the 2:5 relation between Mars and
the asteroids.

“We thus close with the law we enunciated: _Each planet has formed the
next in the series at one of the adjacent commensurable-period points,
corresponding to 1:2, 2:5, 1:3, and in one instance 3:5, of its mean
motion, each then displacing the other slightly sunward, thus making of
the solar system an articulated whole, an inorganic organism, which not
only evolved but evolved in a definite order, the steps of which
celestial mechanics enables us to retrace_.

“The above planetary law may perhaps be likened to Mendelief’s law for
the elements. It, too, admits of prediction. Thus in conclusion I
venture to forecast that when the nearest trans-Neptunian planet is
detected it will be found to have a major axis of very approximately
47.5 astronomical units, and from its position a mass comparable with
that of Neptune, though probably less; while, if it follows a feature of
the satellite systems which I have pointed out elsewhere, its
excentricity should be considerable, with an inclination to match.”

The last paragraph we shall have reason to recall again.

This paper on the “Origin of the Planets” has been called the most
speculative of Percival’s astronomical studies, and so it is; but it
fascinated him, and is interesting not more in itself, than as an
illustration of the inquiring and imaginative trend of his mind and of
the ease with which intricate mathematical work came to the aid of an
idea.

Meanwhile his reputation was growing in Europe. At the end of 1909 he is
asked to send to the German National Museum in Munich some
transparencies of his fundamental work on Mars and other planets with
Dr. Slipher’s star spectra, and Dr. Max Wolf of Heidelberg who writes
the letter adds: “I believe there is no American astronomer, except
yours, [sic] invited till now to do so.” A year later the firm in Jena
which had just published a translation of his “Soul of the Far East”
wants to do the same for “Mars as the Abode of Life.” In August 1914 he
writes to authorize a second French edition of this last book which had
been published with the title “Evolution des Mondes.” Every other year,
he took a vacation of a few weeks in Europe to visit his astronomic
friends, and to speak at their societies. We have seen how he did so
after his marriage in 1908. He went with Mrs. Lowell again in the spring
of 1910, giving lectures before the Société Astronomique in Paris, and
the Royal Institution in London, and once more, two years later, when we
find him entertained and speaking before several scientific bodies in
both Paris and London. That autumn he was confined to the house by
illness; and although he improved and went to Flagstaff in March, he
writes of himself in August 1913 as “personally still on the retired
list.” In the spring it was thought wise for him to take another
vacation abroad; and since his wife was recovering from an operation he
went alone. He saw his old friends in France and England and enjoyed
their hospitality; but he did not feel well, and save for showing at the
Bureau des Longitudes “some of our latest discoveries” he seems to have
made no addresses. He sailed back on the _Mauretania_ on August 1, just
before England declared war, and four days later she was instructed to
run to Halifax, which she did, reaching it the following day.

That was destined to be his last voyage, for although he seemed well
again he was working above his strength. His time in these years was
divided between Flagstaff, where his days and nights were spent in
observing and calculating, and Boston, where the alternative was between
calculations and business. He was always busy and when one summer he
hired a house at Marblehead near to his cousins Mr. and Mrs. Guy Lowell
he would frequently drop in to see them; and was charming when he did
so; but could not spare the time to take a meal there, and never stayed
more than five minutes.




                              CHAPTER XIX
                THE SEARCH FOR A TRANS-NEPTUNIAN PLANET


We must now return to the last paragraph of his “Memoir on the Origin of
the Planets,” where he suggests the probable distance of a body beyond
Neptune. In fact he had long been interested in its existence and
whereabouts. By 1905 his calculations had given him so much
encouragement that the Observatory began to search for the outer planet,
which he then expected would be like Neptune, low in density, large and
bright, and therefore much more easily detected than it turned out to
be. But the photographs taken in 1906, with a well planned routine
search the next year revealed nothing, and he became distrustful of the
data on which he was working. In March 1908, one finds in his
letter-books from the office in Boston the first of a series of letters
to Mr. William T. Garrigan of the Naval Observatory and Nautical
Almanack about the residuals of Uranus—that is the residue in the
perturbations of its normal orbit not accounted for by those due to the
known planets. He suggests including later data than had hitherto been
done; asks what elements other astronomers had taken into account in
estimating the residuals; points out that for different periods they are
made up on different theories in the publications of Greenwich
Observatory, and that some curious facts appear from them. About his own
calculation he writes on December 28, 1908: “The results so far are both
interesting and promising.” He was hard at work on the calculations for
such a planet, based upon the residuals of Uranus, and assisted by a
corps of computers, with Miss Elizabeth Williams, now Mrs. George Hall
Hamilton of the Observatory at Mandeville, Jamaica, at their head.

Before trying to explain the process by which he reached his results it
may be well to give his own account of the discovery of Neptune by a
similar method:[39]

“Neptune has proved a planet of surprises. Though its orbital revolution
is performed direct, its rotation apparently takes place backward, in a
plane tilted about 35° to its orbital course. Its satellite certainly
travels in this retrograde manner. Then its appearance is unexpectedly
bright, while its spectrum shows bands which as yet, for the most part,
defy explanation, though they state positively the vast amount of its
atmosphere and its very peculiar constitution. But first and not least
of its surprises was its discovery,—a set of surprises, in fact. For
after owing recognition to one of the most brilliant mathematical
triumphs, it turned out not to be the planet expected.

“‘Neptune is much nearer the Sun than it ought to be,’ is the
authoritative way in which a popular historian puts the intruding planet
in its place. For the planet failed to justify theory by not fulfilling
Bode’s law, which Leverrier and Adams, in pointing out the disturber of
Uranus, assumed ‘as they could do no otherwise.’ Though not strictly
correct, as not only did both geometers do otherwise, but neither did
otherwise enough, the quotation may serve to bring Bode’s law into
court, as it was at the bottom of one of the strangest and most
generally misunderstood chapters in celestial mechanics.

“Very soon after Uranus was recognized as a planet, approximate
ephemerides of its motion resulted in showing that it had several times
previously been recorded as a fixed star. Bode himself discovered the
first of these records, one by Mayer in 1756, and Bode and others found
another made by Flamsteed in 1690. These observations enabled an
elliptic orbit to be calculated which satisfied them all. Subsequently
others were detected. Lemonnier discovered that he had himself not
discovered it several times, cataloguing it as a fixed star. Flamsteed
was spared a like mortification by being dead. For both these observers
had recorded it two or more nights running, from which it would seem
almost incredible not to have suspected its character from its change of
place.

“Sixteen of these pre-discovery observations were found (there are now
nineteen known), which with those made upon it since gave a series
running back a hundred and thirty years, when Alexis Bouvard prepared
his tables of the planet, the best up to that time, published in 1821.
In doing so, however, he stated that he had been unable to find any
orbit which would satisfy both the new and the old observations. He
therefore rejected the old as untrustworthy, forgetting that they had
been satisfied thirty years before, and based his tables solely on the
new, leaving it to posterity, he said, to decide whether the old
observations were faulty or whether some unknown influence had acted on
the planet. He had hardly made this invidious distinction against the
accuracy of the ancient observers when his own tables began to be out
and grew seriously more so, so that within eleven years they quite
failed to represent the planet.

“The discrepancies between theory and observation attracted the
attention of the astronomic world, and the idea of another planet began
to be in the air. The great Bessel was the first to state definitely his
conviction in a popular lecture at Königsberg in 1840, and thereupon
encouraged his talented assistant Flemming to begin reductions looking
to its locating. Unfortunately, in the midst of his labors Flemming
died, and shortly after Bessel himself, who had taken up the matter
after Flemming’s death.

“Somewhat later Arago, then head of the Paris observatory, who had also
been impressed with the existence of such a planet, requested one of his
assistants, a remarkable young mathematician named Leverrier, to
undertake its investigation. Leverrier, who had already evidenced his
marked ability in celestial mechanics, proceeded to grapple with the
problem in the most thorough manner. He began by looking into the
perturbations of Uranus by Jupiter and Saturn. He started with Bouvard’s
work, with the result of finding it very much the reverse of good. The
farther he went, the more errors he found, until he was obliged to cast
it aside entirely and recompute these perturbations himself. The
catalogue of Bouvard’s errors he gave must have been an eye-opener
generally, and it speaks for the ability and precision with which
Leverrier conducted his investigation that neither Airy, Bessel, nor
Adams had detected these errors, with the exception of one term noticed
by Bessel and subsequently by Adams.[40] The result of this
recalculation of his was to show the more clearly that the
irregularities in the motion of Uranus could not be explained except by
the existence of another planet exterior to him. He next set himself to
locate this body. Influenced by Bode’s law, he began by assuming it to
lie at twice Uranus’ distance from the Sun, and, expressing the observed
discrepancies in longitude in equations, comprising the perturbations
and possible errors in the elements of Uranus, proceeded to solve them.
He could get no rational solution. He then gave the distance and the
extreme observations a certain elasticity, and by this means was able to
find a position for the disturber which sufficiently satisfied the
conditions of the problem. Leverrier’s first memoir on the subject was
presented to the French Academy on November 10, 1845, that giving the
place of the disturbing planet on June 1, 1846. There is no evidence
that the slightest search in consequence was made by anybody, with the
possible exception of the Naval Observatory at Washington. On August 31
he presented his third paper, giving an orbit, mass, and more precise
place for the unknown. Still no search followed. Taking advantage of the
acknowledging of a memoir, Leverrier, in September, wrote to Dr. Galle
in Berlin asking him to look for the planet. The letter reached Galle on
the 23rd, and that very night he found a planet showing a disk just as
Leverrier had foretold, and within 55′ of its predicted place.

“The planet had scarcely been found when, on October 1, a letter from
Sir John Herschel appeared in the _London Athenaeum_ announcing that a
young Cambridge graduate, Mr. J. C. Adams, had been engaged on the same
investigation as Leverrier, and with similar results. This was the first
public announcement of Mr. Adams’ labors. It then appeared that he had
started as early as 1843, and had communicated his results to Airy in
October, 1845, a year before. Into the sad set of circumstances which
prevented the brilliant young mathematician from reaping the fruit of
what might have been his discovery, we need not go. It reflected no
credit on any one concerned except Adams, who throughout his life
maintained a dignified silence. Suffice it to say that Adams had found a
place for the unknown within a few degrees of Leverrier’s; that he had
communicated these results to Airy; that Airy had not considered them
significant until Leverrier had published an almost identical place;
that then Challis, the head of the Cambridge Observatory, had set to
work to search for the planet but so routinely that he had actually
mapped it several times without finding that he had done so, when word
arrived of its discovery by Galle.

“But now came an even more interesting chapter in this whole strange
story. Mr. Walker at Washington and Dr. Petersen of Altona independently
came to the conclusion from a provisional circular orbit for the
newcomer that Lalande had catalogued in the vicinity of its path. They
therefore set to work to find out if any Lalande stars were missing. Dr.
Petersen compared a chart directly with the heavens to the finding a
star absent, which his calculations showed was about where Neptune
should have been at the time. Walker found that Lalande could only have
swept in the neighborhood of Neptune on the 8th and 10th of May, 1795.
By assuming different eccentricities for Neptune’s orbit under two
hypotheses for the place of its perihelion, he found a star catalogued
on the latter date which sufficiently satisfied his computations. He
predicted that on searching the sky this star would be found missing. On
the next fine evening Professor Hubbard looked for it, and the star was
gone. It had been Neptune.[41]

“This discovery enabled elliptic elements to be computed for it, when
the surprising fact appeared that it was not moving in anything
approaching the orbit either Leverrier or Adams had assigned. Instead of
a mean distance of 36 astronomical units or more, the stranger was only
at 30. The result so disconcerted Leverrier that he declared that ‘the
small eccentricity which appeared to result from Mr. Walker’s
computations would be incompatible with the nature of the perturbations
of the planet Herschel,’ as he called Uranus. In other words, he
expressly denied that Neptune was his planet. For the newcomer proceeded
to follow the path Walker had computed. This was strikingly confirmed by
Mauvais’ discovering that Lalande had observed the star on the 8th of
May as well as on the 10th, but because the two places did not agree, he
had rejected the first observation, and marked the second as doubtful,
thus carefully avoiding a discovery that actually knocked at his door.

“Meanwhile Peirce had made a remarkable contribution to the whole
subject. In a series of profound papers presented to the American
Academy, he went into the matter more generally than either of the
discoverers, to the startling conclusion ‘that the planet Neptune is not
the planet to which geometrical analysis had directed the telescope, and
that its discovery by Galle must be regarded as a happy accident.’[42]
He first proved this by showing that Leverrier’s two fundamental
propositions,—

“1. That the disturber’s mean distance must be between 35 and 37.9
astronomical units;

“2. That its mean longitude for January 1, 1800, must have been between
243° and 252°,—were incompatible with Neptune. Either alone might be
reconciled with the observations, but not both.

“In justification of his assertion that the discovery was a happy
accident, he showed that three solutions of the problem Leverrier had
set himself were possible, all equally complete and decidedly different
from each other, the positions of the supposed planet being 120° apart.
Had Leverrier and Adams fallen upon either of the outer two, Neptune
would not have been discovered.[43]

“He next showed that at 35.3 astronomical units, an important change
takes place in the character of the perturbations because of the
commensurability of period of a planet revolving there with that of
Uranus. In consequence of which, a planet inside of this limit might
equally account for the observed perturbations with the one outside of
it supposed by Leverrier. This Neptune actually did. From not
considering wide enough limits, Leverrier had found one solution,
Neptune fulfilled the other.[44] And Bode’s law was responsible for
this. Had Bode’s law not been taken originally as basis for the
disturber’s distance, those two great geometers, Leverrier and Adams,
might have looked inside.

“This more general solution, as Peirce was careful to state, does not
detract from the honor due either to Leverrier or to Adams. Their
masterly calculations, the difficulty of which no one who has not had
some experience of the subject can appreciate, remain as an imperishable
monument to both, as does also Peirce’s to him.”

The facts, that is what was done and written, are of course correct; but
the conclusions drawn from them are highly controversial to the present
day.

The calculations for finding an unknown planet by the perturbations it
causes in the orbit of another are extremely difficult, the more so when
the data are small and uncertain. For Percival they were very small
because Neptune,—nearest to the unknown body,—had been discovered so
short a time that its true orbit, apart from the disturbances therein
caused by other planets, was by no means certain. In fact Percival tried
to analyze its residuals, but they yielded no rational result. This left
only what could be gleaned from Uranus after deducting the perturbations
caused by Neptune, and that was small indeed. In 1845, when the
calculations were made which revealed that planet, “the outstanding
irregularities of Uranus had reached the relatively huge sum of 133″.
To-day its residuals do not exceed 4.5″ at any point of its path.”

Then there are uncertainties depending on errors of observation, which
may be estimated by the method of least squares of the differences
between contemporary observations. Moreover there is the uncertainty
that comes from not knowing how much of the observed motion is to be
attributed to a normal orbit regulated by the Sun, and how much to the
other planets, including the unknown. Its true motion under these
influences can be ascertained only by observing it for a long time, and
by taking periods sufficiently far apart to distinguish the continuing
effects of the known bodies from those that flow from an unknown source.
This was the ingenious method devised by Leverrier as a basis for his
calculations, and he thereby got his residuals caused by the unknown
planet in a form that could be handled.

Finally there was the uncertainty whether the residual perturbations,
however accurately determined, were caused by one or more outer bodies.
Of this Percival was, of course, well aware, and in fact, in his study
of the comets associated with Jupiter he had pointed out that there
probably was a planet far beyond the one for which he was now in search.
But, as no one has ever been able to devise a formula for the mutual
attraction of three bodies, he could calculate only for a single body
that would account as nearly as possible for the whole of the residuals.

Thus he knew that his work was an approximation; near enough, he hoped,
to lead to the discovery of the unknown.

The various elements in the longitude of a planet’s orbit, that is in
the plane of the ecliptic, that are affected by and affect another, are:

a—The length of its major, or longest, axis.

n—Its mean motion, which depends on the distance from the Sun.

ε—The longitude at a given time, that is its place in its orbit.

e—The eccentricity of its orbit, that is how far it is from a circle.

ῶ—The place of its perihelion, that is the position of its nearest
approach to the Sun.

(These last two determine the shape of the ellipse, and the direction of
its longer axis with respect to that of the other planet.)

m—Its mass.

Now formulas, or series of equations, that express the perturbations
caused by one planet in the orbit of another must contain all these
elements, because all of them affect the result. But there are too many
of them for a direct solution. Therefore Leverrier assumed a distance of
the unknown planet from the Sun, and with it the mean motion which is
proportional to that distance; worked out from the residuals of Uranus
at various dates a series of equations in terms of the place of the
unknown in its orbit; and then found what place therein at a given time
would give results reducing the residuals to a minimum—that is, would
come nearest to accounting for them. In fact, supposing that the unknown
planet would be about the distance from the Sun indicated by Bode’s law,
the limits within which he assumed trial distances were narrow, and, as
it proved, wholly beyond the place where it was found. This method,
which in its general outline Percival followed, consisted therefore of a
process of trial and error for the distance (with the mean motion) and
for the place of X in its orbit (ε). For the other three elements (e, ῶ
and m) he used in the various solutions 24 to 37 equations drawn from
the residuals of Uranus at different dates, and expressed in terms of ε.
He did this in order to have several corroborative calculations, and to
discover which of them accorded most closely with the perturbations
observed.

We have seen that in 1908-09 Percival was inquiring about the exact
residuals of Uranus, and he must have been at work on them soon
afterwards, for on December 1, 1910, he writes to Mr. Lampland that Miss
Williams, his head computer, and he have been puzzling away over that
trans-Neptunian planet, have constructed the curve of perturbations, but
find some strange things, looking as if Leverrier’s later theory of
Uranus were not exact. This work had been done by Leverrier’s methods
“but with extensions in the number and character of the terms calculated
in the perturbation in order to render it more complete.” Though
uncertain of his results, he asks Mr. Lampland, in April 1911, to look
for the planet. But he was by no means himself convinced that his data
were accurate, and he computed all over again with the residuals given
by Gaillot, which he considered more accurate than Leverrier’s in regard
to the masses, and therefore the attractions, of the known planets
concerned. Incidentally he remarks at this point in his Memoir,[45] in
speaking of works on celestial mechanics, that “after excellent
analytical solutions, values of the quantities involved are introduced
on the basis apparently of the respect due to age. Nautical Almanacs
abet the practice by never publishing, consciously, contemporary values
of astronomic constants; thus avoiding committal to doubtful results by
the simple expedient of not printing anything not known to be wrong.”
His result for X, as he called the planet he was seeking, computed by
Gaillot’s residuals, differed from that found in using Leverrier’s
figures by some forty degrees to the East, and on July 8 he telegraphs
Mr. Lampland to look there.

These telegrams to Mr. Lampland continue at short intervals for a long
time with constant revisions and extensions in the calculations; and, as
he notes, every new move takes weeks in the doing; but all without
finding planet X. Perhaps it was this disappointment that led him to
make the even more gigantic calculation printed in the Memoir, where he
says: “In the present case, it seemed advisable to pursue the subject in
a different way, longer and more laborious than these earlier methods,
but also more certain and exact: that by a true least-square method
throughout. When this was done, a result substantially differing from
the preliminary one was the outcome. It both shifted the minimum and
bettered the solution. In consequence, the whole work was done _de novo_
in this more rigorous way, with results which proved its value.”

Then follow many pages of transformations which, as the guide books say
of mountain climbing, no one should undertake unless he is sure of his
feet and has a perfectly steady head. But anyone can see that, even in
the same plane, the aggregate attractions of one planet on another,
pulling eventually from all possible relative positions in their
respective elliptical orbits with a force inversely as the square of the
ever-changing distance, must form a highly complex problem. Nor, when
for one of them the distance, velocity, mass, position and shape of
orbit are wholly unknown, so that all these things must be represented
by symbols, will anyone be surprised if the relations of the two bodies
are expressed by lines of these, following one another by regiments over
the pages. In fact the Memoir is printed for those who are thoroughly
familiar with this kind of solitaire.

For the first trial and error Percival assumed the distance of X from
the Sun to be 47.5 planetary units (the distance of the Earth from the
Sun being the unit), as that seemed on analogy a probable, though by no
means a certain, distance. With this as a basis, and with the actual
observations of Uranus brought to the nearest accuracy by the method of
least-squares of errors, he finds the eccentricity, the place of the
perihelion and the mass of X in terms of its position in its orbit. Then
he computes the results for about every ten degrees all the way round
the orbit, and finds two positions, almost opposite, near 0° and near
180°, which reduce the residuals to a minimum—that is which most nearly
account for the perturbations. Each of these thirty tried positions
involved a vast amount of computation, but more still was to come.

Finally, to be sure that he had covered the ground and left no loophole
for X to escape, he tried, beside the 47.5 he had already used, a series
of other possible distances from the Sun,—40.5, 42.5, 45, 51.25
units,—each of them requiring every computation to be done over again.
But the result was satisfactory, for it showed that the residuals were
most nearly accounted for by a distance not far from 45 units (or a
little less if the planet was at the opposite side of its orbit), and
that the residuals increased for a distance greater or less than this.
But still he was not satisfied, and for greater security he took up
terms of the second and third order—very difficult to deal with—but
found that they made no substantial difference in the result.

So much for the longitude of X (that is its orbit and position in the
plane of the ecliptic) but that was not all, for its orbit might not lie
in that plane but might be inclined to it, and like all the other
planets he supposed it more or less so—more he surmised. Although he
made some calculations on the subject he did not feel that any result
obtained would be reliable, and if the longitude were near enough he
thought the planet could be found. He says:

“To determine the inclination of the orbit of the unknown from the
residuals in latitude of _Uranus_ has proved as inconclusive as
Leverrier found the like attempt in the case of _Neptune_.

“The cause of failure lies, it would seem, in the fact that the elements
of X enter into the observational equations for the latitude. Not only e
and ῶ are thus initially affected but ε as well. Hence as these are
doubtful from the longitude results, we can get from the latitude ones
only doubtfulness to the second power.” Nevertheless he makes some
calculations on the subject which, however, prove unsatisfactory.

Such in outline was his method of calculating the probable orbit and
position in the sky of the trans-Neptunian planet; an herculean labor
carried out with infinite pains, and attaining, not absolute
definiteness, but results from the varying solutions sufficiently alike
to warrant the belief in a close approximation. In dealing with what he
calls the credentials for the acceptance of his results, he points out
that one of his solutions for X in which he has much confidence, reduces
the squares of the residuals to be accounted for by ninety per cent.,
and in the case of some of the others almost to nothing. Yet he had no
illusions about the uncertainty of the result, for in the conclusions of
the Memoir he says:

“But that the investigation opens our eyes to the pitfalls of the past
does not on that account render us blind to those of the present. To
begin with, the curves of the solutions show that a proper change in the
errors of observation would quite alter the minimum point for either the
different mean distances or the mean longitudes. A slight increase of
the actual errors over the most probable ones, such as it by no means
strains human capacity for error to suppose, would suffice entirely to
change the most probable distance of the disturber and its longitude at
the epoch. Indeed the imposing ‘probable error’ of a set of observations
imposes on no one familiar with observation, the actual errors
committed, due to systematic causes, always far exceeding it.

“In the next place the solutions themselves tell us of alternatives
between which they leave us in doubt to decide. If we go by residuals
alone, we should choose those solutions which have their mean longitudes
at the epoch in the neighborhood of 0°, since the residuals are there
the smallest. But on the other hand this would place the unknown now and
for many decades back in a part of the sky which has been most
assiduously scanned, while the solutions with ε around 180° lead us to
one nearly inaccessible to most observatories, and, therefore,
preferable for planetary hiding. Between the elements of the two, there
is not much to choose, all agreeing pretty well with one another.

“Owing to the inexactitude of our data, then, we cannot regard our
results with the complacency of completeness we should like.”

The bulk of the computations for the trans-Neptunian planet were
finished by the spring of 1914, and in April he sent to Flagstaff from
Boston, where the work had been done, two of the assistant computers.
The final Memoir he read to the American Academy of Arts and Sciences on
January 13, 1915; and printed in the spring as a publication of the
Observatory. Naturally he was deeply anxious to see the fruit from such
colossal labor. In July, 1913, he had written to Mr. Lampland:
“Generally speaking what fields have you taken? Is there nothing
suspicious?” and in May, 1914, “Don’t hesitate to startle me with a
telegram ‘FOUND.’” Again, in August, he writes to Dr. Slipher: “I feel
sadly of course that nothing has been reported about X, but I suppose
the bad weather and Mrs. Lampland’s condition may somewhat explain it”;
and to Mr. Lampland in December: “I am giving my work before the Academy
on January 13. It would be thoughtful of you to announce the actual
discovery at the same time.” Through the banter one can see the craving
to find the long-sought planet, and the grief at the baffling of his
hopes. That X was not found was the sharpest disappointment of his life.

If so much labor without tangible result gave little satisfaction, there
was still less glory won by a vast calculation that did not prove itself
correct. Curiously enough, he always enjoyed more recognition among
astronomers in Europe than in America; for here, as a highly
distinguished member of the craft recently remarked, he did not belong
to the guild. He was fond of calling himself an amateur—by which he
meant one who worked without remuneration—and of noting how many of the
great contributors to science were in that category. The guild here was
not readily hospitable to those who had not been trained in the regular
treadmill; and it had been shocked by his audacity in proclaiming a
discovery of intelligent handiwork on Mars. So for the most part he
remained to the end of his life an amateur in this country; though what
would have been said had he succeeded in producing, by rigorous
calculation, an unknown planet far beyond the orbit of Neptune, it is
interesting to conjecture, but difficult to know, for the younger
generation of astronomers had not then come upon the stage nor the older
ones outlived their prejudice.

The last eighteen months of his life were spent as usual partly at
Flagstaff, where he was adding to the buildings, partly in Boston, and
in lecturing. In May, 1916, he writes to Sig. Rigano of “Scientia” that
he has not time to write an article for his Review, and adds:
“Eventually I hope to publish a work on each planet—the whole connected
together—but the end not yet.” Fortunately he did not know how near it
was.

In May he lectured at Toronto; and in the autumn in the Northwest on
Mars and other planets, at Washington State and Reed Colleges, and the
universities of Idaho, Washington, Oregon and California. These set
forth his latest views, often including much that had been discovered at
Flagstaff and elsewhere since his earlier books were published; for his
mind was far from closed to change of opinion on newly discovered
evidence. It was something of a triumphal procession at these
institutions; but it was too much.

More exhausted than he was himself aware, he returned to Flagstaff eager
about a new investigation he had been planning on Jupiter’s satellites.
It will be recalled that he had found the exact position of the gap in
Saturn’s rings accounted for if the inner layers of the planet rotated
faster and therefore were more oblate than the visible gaseous surface.
Now the innermost satellite of Jupiter (the Vth) was farther off than
the simple relation between distance and period should make it, a
difference that might be explained if in Jupiter, as in Saturn, the
molten inner core were more oblate than the outer gaseous envelope. To
ascertain this the distance of the satellite V. must be determined
exactly, and with Mr. E. C. Slipher he was busy in doing so night after
night through that of November 11th. But he was overstrained, and the
next day, November 12, 1916, not long after his return to Flagstaff, an
attack of apoplexy brought to a sudden close his intensely active life.
Before he became unconscious he said that he always knew it would come
thus, but not so soon.

He lies buried in a mausoleum built by his widow close to the dome where
his work was done.




                               CHAPTER XX
                            PLUTO FOUND[46]


Percival had long intended that his Observatory should be permanent, and
that his work, especially on the planets, should be forever carried on
there with an adequate foundation. Save for an income to his wife during
her lifetime, he therefore left his whole fortune in a trust modeled on
the lines of the Lowell Institute in Boston, created eighty years
earlier by his kinsman John Lowell, Jr. The will provides for a single
trustee who appoints his own successor; the first being his cousin Guy
Lowell, the next the present trustee, Percival’s nephew, Roger Lowell
Putnam. Dr. V. M. Slipher and Mr. C. O. Lampland, who have been at the
Observatory from an early time, are the astronomers in charge, carrying
on the founder’s principles of constantly enlarging the field of study,
and using for the purpose the best instrumental equipment to be
procured.

Of course the search was continued for the planet X, but without
success, and for a time almost without hope, not only because its body
is too small to show a disk, but also by reason of the multitude of
stars of like size in that crowded part of the heavens, the Milky Way,
where it is extremely difficult to detect one that has moved. It was as
if out of many thousand pins thrown upon the floor one were slightly
moved and someone were asked to find which it was. Mere visual
observation was clearly futile, for no man could record the positions of
all the points of light from one night to another. The only way to
conduct a systematic search was through an enduring record, that is by
taking photographs of the probable sections of the sky, and comparing
two of the same section taken a few days apart to discover a point of
light that had changed its place—no simple matter when more than one
hundred thousand stars showed upon a single plate. This process Percival
tried, but although his hopes were often raised by finding bodies that
moved, they proved to be asteroids hitherto unknown,[47] and the X
sought so long did not appear.[48]

Percival had felt the need of a new photographic telescope of
considerable light power and a wider field, and an attempt was made to
borrow such an instrument, for use while one was being manufactured, but
in vain. Then came the war when optical glass for large lenses could not
be obtained, and before it was over Percival had died. After his death
Guy Lowell, the trustee, took up the project, but also died too soon to
carry it out. At last in 1929 the lens needed was obtained, the
instrument completed in the workshop of the Observatory, and the search
renewed in March with much better prospects. Photographs of section
after section of the region where X was expected to be were taken and
examined by a Blink comparator. This is a device whereby two photographs
of slightly different dates could be seen through a microscope at the
same time as if superposed. But with all the improvement in apparatus
months of labor revealed nothing.

After nearly a year of photographing, and comparing plates, Mr. Clyde W.
Tombaugh, a young man brought up on a farm but with a natural love of
astronomy, was working in this search at Flagstaff, when he suddenly
found, on two plates taken January 23 and 29, 1930, a body that had
moved in a way to indicate, not an asteroid, but something vastly
farther off. It was followed, and appeared night after night in the path
expected for X at about the distance from the sun Percival had
predicted. Before giving out any information it was watched for seven
weeks, until there could be no doubt from its movements that it was a
planet far beyond Neptune, and was following very closely the track
which his calculations had foretold. Then, on his birthday, March 13,
the news was given to the world.

Recalling Percival’s own statement: “Owing to the inexactitude of our
data, then, we cannot regard our results with the complacency of
completeness we should like,” one inquires eagerly how nearly the actual
elements in the orbit of the newly found planet agree with those he
calculated. To this an answer was given by Professor Henry Norris
Russell of Princeton, the leading astronomer in this country, in an
article in the _Scientific American_ for December, 1930. He wrote as
follows:

“The orbit, now that we know it, is found to be so similar to that which
Lowell predicted from his calculations fifteen years ago that it is
quite incredible that the agreement can be due to accident. Setting
prediction and fact side by side we have the following table of
characteristics:

                                _Predicted_               _Actual_
  Period                          282 years                 249.17
  Eccentricity                        0.202                  0.254
  Longitude of perihelion              205°               202° 30′
  Perihelion passage                 1991.2                1989.16
  Inclination                     about 10°                 17° 9′
  Longitude of node not                                   109° 22′
  predicted

“Lowell saw in advance that the perturbations of the latitudes of Uranus
and Neptune (from which alone the position of the orbit plane of the
unknown planet could be calculated) were too small to give a reliable
result and contented himself with the prophecy that the inclination,
like the eccentricity, would be considerable. For the other four
independent elements of the orbit, which are those that Lowell actually
undertook to determine by his calculations, the agreement is good in all
cases, the greatest discrepancy being in the period, which is
notoriously difficult to determine by computations of this sort. In view
of Lowell’s explicit statement that since the perturbations were small
the resulting elements of the orbit could at best be rather rough
approximations, the actual accordance is all that could be demanded by a
severe critic.

“Even so, the table does not tell the whole story. Figure 1[49] shows
the actual and the predicted orbits, the real positions of the planet at
intervals from 1781 to 1989, and the positions resulting from Lowell’s
calculations. It appears at once that the predicted positions of the
orbit and of the planet upon it were nearest right during the 19th
century and the early part of the 20th, while at earlier and later dates
the error rapidly increased. Now this (speaking broadly) is just the
interval covered by the observations from which the influence of the
planet’s attraction could be determined and, therefore, the interval in
which calculation could find the position of the planet itself with the
least uncertainty.

    [Illustration: Predicted and Actual Orbits of PLUTO]

“In the writer’s judgment this test is conclusive.”[50]

Later observations, and computations of the orbit of Pluto, do not vary
very much from those that Professor Russell had when he wrote. Two of
the most typical—giving more elements—are as follows:

                       _Predicted_    _Nicholson and     _F. Zagar_
                                      Mayall_
  Period               282 years      249.2              248.9
  Eccentricity         0.202          0.2461             0.2472
  Longitude of         204.9          222° 23′ 20″ .17   222° 29′ 39″ .4
    perihelion
  Perihelion passage   1991.2         1889.75            1888.4
  Inclination          about 10°      17° 6′ 58″ .4      17° 6′ 50″ .8
  Semi-major axis      43.            39.60              39.58
  Perihelion           34.31          29.86              29.80
    distance
  Aphelion distance    51.69          49.35              49.36

Except for the eccentricity, and the inclination which he declared it
impossible to calculate, these results have proved as near as, with the
uncertainty of his data, he could have expected; and in regard to the
position of the planet in its orbit it will be recalled that he found
two solutions on opposite sides, both of which would account almost
wholly for the residuals of Uranus. The one that came nearest to doing
so he had regarded as the least probable because it placed the planet in
a part of the sky that had been much searched without finding it; but it
was there that Pluto appeared—a striking proof of his rigorous analytic
method.

But the question of its mass has raised serious doubts whether Pluto can
have caused the perturbations of Uranus from which he predicted its
presence, for if it has no significant mass the whole basis of the
calculation falls to the ground, and there has been found a body
travelling, by a marvellous coincidence, in such an orbit that, if large
enough, it would produce the perturbations but does not do so.[51] Now
as there is no visible satellite to gauge its attraction, and as it will
be long before Pluto in its eccentric orbit approaches Neptune or Uranus
closely enough to measure accurately by that means, the mass cannot yet
be determined with certainty. What is needed are measures of position of
the highest possible accuracy of Neptune and Uranus, long continued and
homogeneous.

The reasons for the doubt about adequate mass are two.[52] One that with
the largest telescopes it shows no visible disk, and must therefore be
very small in size, and hence in mass unless its density is much
greater, or its albedo far less, than those of any other known planet.
The other substantially that the orbits of Uranus and Neptune can be,
and are more naturally, explained by assuming appropriate elements
therefor, without the intervention of Pluto’s disturbing force. This is
precisely what Percival stated in discussing the correctness of the
residuals—that it was always possible to account for the motions of a
planet, whose normal orbit about the sun is not definitely ascertained,
by throwing any observed divergencies either on errors in the supposed
orbit, or upon perturbations by an unknown body.

The conditions here are quite unlike those at the discovery of Neptune,
for there the existence of the perturbations was clear, because fairly
large, and the orbit predicted was wrong because of an error in the
distance assumed; and the question was whether the presence of Neptune
in the direction predicted, though in a different orbit, was an
accident, or inevitable. Here the predicted orbit is substantially the
actual one, adequate to account for the perturbations of Uranus if such
really exist, and the question is whether they do or not. If not the
discovery of Pluto is a mere unexplained coincidence which has no
connection with the prediction. Whether among recognized uncertainties
it is more rational to suppose a very high density, and very low albedo,
with corresponding perturbations of Uranus and Neptune, whose orbits are
still imperfectly known, or to conclude that a planet, which would
account for these things if dense enough, revolves in fact in the
appropriate path, a mere ghost of itself—a phantom but not a force—one
who is not an astronomer must leave to the professionals.

In the case of both Neptune and Pluto the calculation was certainly a
marvellous mathematical feat, and in accord with the usual practice
whereby the discoverer of a new celestial body is entitled to propose
its name the observers at Flagstaff selected from many suggestions that
of “Pluto” with the symbol [Illustration: ligature, P over L]; and
henceforth astronomers will be reminded of Percival Lowell, by the
planet he found but never saw.

    [Illustration: Decorative wreath]




                               APPENDIX I


   _Professor Henry Norris Russell’s later views on the size of Pluto
  (written to the Biographer and printed with the writer’s consent)._

Later investigations have revealed a very curious situation. When once
the elements of Pluto’s orbit are known, the calculation of the
perturbations which it produces on another planet, such as Neptune, are
greatly simplified. But the problem of finding Pluto’s mass from
observations of Neptune is still none too easy, for the perturbations
affect the calculated values of the elements of Neptune’s orbit, and are
thus “entangled” with them in an intricate fashion.

Nicholson and Mayall, in 1930, attacked the problem, and found that the
perturbations of Neptune by Pluto, throughout the interval from its
discovery to the present, were almost exactly similar to the effects
which would have been produced by certain small changes in the elements
of Neptune’s orbit, so that, from these observations alone, it would
have been quite impossible to detect Pluto’s influence. Outside this
interval of time, the effects of the perturbations steadily diverge from
those of the spurious changes in the orbit, but we cannot go into the
future to observe them, and all we have in the past is two rather
inaccurate observations made in 1795 by Lalande.[53] If the average of
these two discordant observations is taken as it stands, Pluto’s mass
comes out 0.9 times that of the Earth, and this determination is
entitled to very little weight.

Uranus is farther from Pluto, and its perturbations are smaller; but it
has been accurately observed over one and a half revolutions, as against
half a revolution for Neptune, and this greatly favors the separation of
the perturbations from changes in the assumed orbital elements.
Professor E. W. Brown—the most distinguished living student of the
subject—concludes from a careful investigation that the observations of
Uranus show that Pluto’s mass cannot exceed one-half of the Earth’s and
may be much less. In his latest work a great part of the complication is
removed by a curiously simple device. Take the sum of the residuals of
Uranus at any two dates separated by one-third of its period, and
subtract from this the residual at the middle date. Brown proves—very
simply—that the troublesome effect of uncertainties in the eccentricity
and perihelion of the disturbed planet will be completely removed from
the resulting series of numbers, leaving the perturbations much easier
to detect. The curve which expresses their effects, though changed in
shape, can easily be calculated. Applying this method to the longitude
of Uranus, he finds, beside the casual errors of observation, certain
deviations; but these change far more rapidly than perturbations due to
Pluto could possibly do, and presumably arise from small errors in
calculating the perturbations produced by Neptune. When these are
accurately re-calculated, a minute effect of Pluto’s attraction may
perhaps be revealed, but Brown concludes that “another century of
accurate observations appears to be necessary for a determination which
shall have a probable error less than a quarter of the Earth’s mass.”

The conclusion that Pluto’s mass is small is confirmed by its
brightness. Its visual magnitude is 14.9—just equal to that which
Neptune’s satellite Triton would have if brought to the same distance.
(Since Pluto’s perihelion distance is less than that of Neptune, this
experiment is one which Nature actually performs at times.) Now
Nicholson’s observations show that the mass of Triton is between 0.06
and 0.09 times the Earth’s. It is highly probable that Pluto’s mass is
about the same—in which case the perturbations which it produces, even
on Neptune, will be barely perceptible, so long as observations have
their present degree of accuracy.

The value of seven times the Earth’s mass, derived in Percival Lowell’s
earlier calculations, must have been influenced by some error. His
mathematical methods were completely sound—on Professor Brown’s
excellent authority—and the orbit of Planet X which he computed
resembled so closely that of the actual Pluto that no serious
discordance could arise from the difference. But, in this case also, the
result obtained for the mass of the perturbing planet depended
essentially on the few early observations of Uranus as a star, made
before its discovery as a planet, and long before the introduction of
modern methods of precise observation. Errors in these are solely
responsible for the inaccuracy in the results of the analytical
solution.

The question arises, if Percival Lowell’s results were vitiated in this
way by errors made by others more than a century before his birth, why
is there an actual planet moving in an orbit which is so uncannily like
the one he predicted?

There seems no escape from the conclusion that this is a matter of
chance. That so close a set of chance coincidences should occur is
almost incredible; but the evidence assembled by Brown permits of no
other conclusion. Other equally remarkable coincidences have occurred in
scientific experience. A cipher cable-gram transmitting to the Lick
Observatory the place of a comet discovered in Europe was garbled in
transmission, and when decoded gave an erroneous position in the
heavens. Close to this position that evening another undiscovered comet
was found. More recently a slight discrepancy between determinations of
the atomic weight of hydrogen by the mass-spectrograph and by chemical
means led to a successful search for a heavy isotype of hydrogen. Later
and more precise work with the mass-spectrograph showed that the
discrepancy had at first been much over-estimated. Had this error not
been made, heavy hydrogen might not yet have been discovered.

Like this later error, the inaccuracy in the ancient observations, which
led to an over-estimate of the mass and brightness of Pluto, was a
fortunate one for science.

In any event, the initial credit for the discovery of Pluto justly
belongs to Percival Lowell. His analytical methods were sound; his
profound enthusiasm stimulated the search, and, even after his death,
was the inspiration of the campaign which resulted in its discovery at
the Observatory which he had founded.




                              APPENDIX II
                         THE LOWELL OBSERVATORY
                  _by Professor Henry Norris Russell_


The Observatory at Flagstaff is Percival Lowell’s creation. The material
support which he gave it, both during his lifetime and by endowment,
represents but a small part of his connection with it. He chose the
site, which in its combination of excellent observing conditions and the
amenities of everyday life, is still unsurpassed. He selected the
permanent members of the staff and provided for the successor to the
Directorship after his death. Last, but not least, he inspired a
tradition of intense interest in the problems of the universe, and
independent and original thought in attacking them, which survives
unimpaired.

On a numerical basis—whether in number of staff, size of instruments, or
annual budget—the Lowell Observatory takes a fairly modest rank in
comparison with some great American foundations. But throughout its
history it has produced a long and brilliant series of important
discoveries and observations notable especially for originality of
conception and technical skill. Percival Lowell’s own work has been
fully described; it remains to summarize briefly that of the men whom he
chose as his colleagues, presenting it according to its subject, rather
than in chronological order.

The photography of the planets has been pursued for thirty years, mainly
by the assiduous work of E. C. Slipher, and the resulting collections
are unrivalled. Only a small amount of this store has been published or
described in print, but among its successes may be noted the first
photographs of the canals of Mars, and the demonstration by this
impersonal method of the seasonal changes in the dark areas, and of the
occasional appearance of clouds. It is a commonplace that any astronomer
who wants photographs of the planets for any illustrative purpose
instinctively applies to his friends in Flagstaff, and is not likely to
be disappointed.

The discovery of Pluto, and incidentally of many hundreds of asteroids,
has already been described.

An important series of measurements of the radiation from the planets
was made at Flagstaff in 1921 and 1922 by Dr. W. W. Coblentz of the
Bureau of Standards and Dr. C. O. Lampland. Using the 40-inch reflector,
and the vacuum thermocouples which the former had developed, and
employed in measurements of stellar radiation at the Lick Observatory,
and working with and without a water-cell (which transmits most of the
heat carried by the sunlight reflected from a planet, but stops
practically all of that radiated from its own surface), they found that
the true “planetary heat” from Jupiter was so small that its surface
must be very cold, probably below -100° Centigrade, while that from Mars
was considerable, indicating a relatively high temperature. Both
conclusions have been fully confirmed by later work.

Spectroscopic observation has been equally successful. In 1912 Lowell
and Slipher (V. M.) successfully attacked the difficult problem of the
rotation of Uranus. One side of a rotating planet is approaching us, the
other receding. If its image is thrown on a spectroscope, so that its
equatorial regions fall upon the slit, the lines of the spectrum will be
shifted toward the violet on one edge, and the red on the other, and
will cross it at a slant instead of at right angles. This method had
long before been applied to Jupiter and to Saturn and its rings, but
Uranus is so faint as to discourage previous observation. Nevertheless,
with the 24-inch reflector, and a single-prism spectrograph, seven
satisfactory plates were obtained, with an average exposure of 2½ hours,
every one of which showed a definite rotation effect. The mean result
indicated that Uranus rotates in 10¾ hours, with motion retrograde, as
in the case of his satellites. This result was confirmed five years
latter by Leon Campbell at Harvard, who observed regular variations in
the planet’s brightness with substantially the same period.

It has been known since the early days of the spectroscope that the
major planets exhibit in their spectra bands produced by absorption by
the gases of their atmospheres, and that these bands are strongest in
the outer planets. Photographs showing this were first made by V. M.
Slipher at the Lowell Observatory in 1902. To get adequate spectrograms
of Neptune required exposures of 14 and 21 hours—occupying the available
parts of the clear nights of a week. The results well repaid the effort.
The bands which appear faintly in Jupiter are very strong in Uranus, and
enormous in Neptune’s spectrum, cutting out great portions of the red
and yellow, and accounting for the well-known greenish color of the
planet. Only one band in the red was present in Jupiter alone.

For a quarter of a century after this discovery those bands remained one
of the most perplexing riddles of astrophysics. The conviction gradually
grew that they must be due to some familiar gases, but the first hint of
their origin was obtained by Wildt in 1932, who showed that one band in
Jupiter was produced by ammonia gas, and another probably by methane.
These conclusions were confirmed by Dunham in the following year, but
the general solution of the problem was reserved for Slipher and Adel,
who, in 1934, announced that the whole series of unidentified bands were
due to methane. The reason why they had not been identified sooner is
that it requires an enormous thickness of gas to produce them. A tube 45
meters long, containing methane at 40 atmospheres pressure, produces
bands comparable to those in the spectra of Saturn. The far heavier
bands in Neptune indicate an atmosphere equivalent to a layer 25 miles
thick at standard atmospheric pressure. The fainter bands though not yet
observed in the laboratory, have been conclusively identified by the
theory of band-spectra. Ammonia shows only in Jupiter and faintly in
Saturn; the gas is doubtless liquefied or solidified at the very low
temperatures of the outer planets.

The earth’s own atmosphere has also been the subject of discovery at
Flagstaff. The light of a clear moonless sky does not come entirely from
the stars and planets; about one-third of it originates in the upper
air, and shows a spectrum of bright lines and bands. The familiar
auroral line is the most conspicuous of these, but V. M. Slipher, making
long exposures with instruments of remarkably great light-gathering
power, has recently detected a large number of other bands, in the deep
red and even the infra-red. Were our eyes strongly sensitive to these
wave-lengths, the midnight skies would appear ruddy.

Just as the first rays of the rising sun strike the upper layers of the
atmosphere many miles above the surface, new emission bands appear in
the spectrum—to be drowned out soon afterwards by the twilight reflected
from the lower and denser layers; and the reverse process is observable
after sunset.

The origin of these remarkable and wholly unexpected radiations is not
yet determined.

The spectrograph of the Observatory was also employed in observations of
stars, and again led to unexpected discoveries. In 1908, while observing
the spectroscopic binary Beta Scorpii, V. M. Slipher found that the K
line of calcium was sharp on his plates, while all the others were broad
and diffuse. Moreover, while the broad lines shifted in position as the
bright star moved in its orbit, the narrow line remained stationery.
Hartmann, in 1904, had observed a similar line in the spectra of Delta
Orionis, and suggested that it was absorbed in a cloud of gas somewhere
between the sun and the star. Slipher, extending his observations to
other parts of the heavens, found that such stationery calcium lines
were very generally present (in spectra of such types that they were not
masked by heavier lines arising in the stars themselves), and made the
bold suggestion that the absorbing medium was a “general veil” of gas
occupying large volumes of interstellar space.

This hypothesis, which appeared hardly credible at that time, has been
abundantly confirmed—both by the discovery of similar stationery lines
of sodium, and by the theoretical researches of Eddington,—and no one
now doubts that interstellar space is thinly populated by isolated
metallic atoms presumably ejected from some star in the remote past, but
now wandering in the outer darkness, with practically no chance of
returning to the stars.

To secure satisfactory spectroscopic observations of nebulae is often
very difficult. Though some of these objects are of considerable
brightness, they appear as extended luminous surfaces in the heavens,
and in the focal plane of the telescope. The slit of a spectroscope,
which must necessarily be narrow to permit good resolution of the lines,
admits but a beggarly fraction of the nebula’s light. To increase the
size of the telescope helps very little, for, though more light is
collected in the nebular image, this image is proportionately increased
in area, and no more light enters the slit than before.

For the gaseous nebulae, whose spectra consist of separate bright lines,
there is no serious difficulty; but the majority of nebulae have
continuous spectra, and when the small amount of light that traverses
the slit is spread out into a continuous band, it becomes so faint that
prohibitively long exposures would be required to photograph it. It was
at the Lowell Observatory that Dr. V. M. Slipher first devised a way of
meeting this difficulty.

By employing in the camera of the spectrograph (which forms the image of
the spectrum on the plate) a lens of short focus, this image became both
shorter and narrower, thereby increasing the intensity of the light
falling on a given point of the plate in a duplicate ratio. Moreover,
since with this device the image of the slit upon the plate is much
narrower than the slit itself, it became possible to open the slit more
widely and admit much more of the light of the nebula, without spoiling
the definition of the spectral lines.

This simple but ingenious artifice opened up a wholly new field of
observation, and led to discoveries of great importance.

Within the cluster of the Pleiades, and surrounding it, are faint
streaky wisps of nebulosity, which have long been known. One might have
guessed that the spectrum, like that of some other filamentous nebulae,
would be gaseous. But when Slipher photographed it in December 1912
(with an exposure of 21 hours, on three successive nights) he found a
definite continuous spectrum, crossed by strong dark lines of hydrogen
and fainter lines of helium—quite unlike the spectrum of any previously
observed nebula, but “a true copy of that of the brighter stars in the
Pleiades.” Careful auxiliary studies showed that the light which
produced this spectrum came actually from the nebula. This suggested at
once that this nebula is not self-luminous, but shines by the reflected
light of the stars close to it. This conclusion has been fully verified
by later observations, at Flagstaff and elsewhere. It is only under
favorable conditions that one of these vast clouds (probably of thinly
scattered dust) lies near enough to any star to be visibly illuminated.
The rest reveal themselves as dark markings against the background of
the Milky Way.

Similar observations of the Great Nebula of Orion showed that the
conspicuous “nebular” lines found in its brighter portions faded out in
its outer portions, leaving the hydrogen lines bright, while, at the
extreme edge, only a faint continuous spectrum appeared. This again has
been fully explained by Bowen’s discovery of the mechanism of excitation
of nebular radiation by the ultra-violet light from exceedingly hot
stars, and affords a further confirmation of it.

But the most important contribution of the new technique was in the
observation of the spiral nebulae. Their spectra are continuous and so
faint that previous instruments brought out only tantalizing suggestions
of dark lines. With the new spectrograph, beautiful spectra were
obtained, showing numerous dark lines, of just the character that might
have been expected from vast clouds of stars of all spectral types. This
provided the first definite indication of one of the greatest of modern
astronomical discoveries—that the white nebulae are external galaxies,
of enormous dimensions, and at distances beyond the dreams of an earlier
generation.

By employing higher dispersion, spectra were secured which permitted the
measurement of radial velocity. The first plates, of the Andromeda
Nebula, revealed the almost unprecedented speed of 300 kilometers per
second toward the Sun. Later measures of many other nebulae showed that
this motion was, for a nebula, unusually slow, but remarkable in its
direction, for practically all the others were receding.

Similar measures upon globular star-clusters showed systematic
differences in various parts of the heavens, which indicated that,
compared with the vast system of these clusters, the Sun is moving at
the rate of nearly 300 kilometers per second—a motion which is now
attributed to its revolution, in a vast orbit, about the center of the
Galaxy, as a part of the general rotation of the latter.

The velocities of the nebulae reveal substantially the same solar
motion, but, over and above this, an enormous velocity of recession,
increasing with the faintness and probable distance of the nebulae.

This, again, was a discovery of primary importance. It has been
confirmed at other observatories and observations with the largest
existing telescope have revealed still greater velocities of recession
in nebulae too faint to observe at Flagstaff. How this has led to the
belief that the material universe is steadily expanding and that its
ascertainable past history covers only some two thousand millions of
years, can only be mentioned here.

This is a most remarkable record for thirty years’ work of a single
observatory with a regular staff never exceeding four astronomers. But
its distinction lies less in the amount of the work than in its
originality and its fertile character in provoking extensive and
successful researches at other observatories as well.

All this is quite in the spirit of its Founder, and, to his colleagues
in the science, makes the Observatory itself seem his true monument. His
body lies at rest upon the hill, but, in an unquenched spirit of eager
investigation, his soul goes marching on.




                               FOOTNOTES


[1]It is dated Boston, August 24th, but the year does not appear. She
    was abroad and he at home in the summers of 1882 and 1887.

[2]Before leaving Korea he spent two delightful weeks at the Footes’.

[3]This came about a month later than ours.

[4](_Atlantic Monthly_, Nov. 1886, “A Korean Coup d’Etat”).

[5]“The Life and Letters of Lafcadio Hearn by Elizabeth Bisland,” Vol.
    I, p. 459.

[6]_Ib._, Vol. II, p. 28.

[7]_Ib._, Vol. II, p. 30.

[8]_Ib._, Vol. II, p. 487. See also pp. 479, 505. Percival’s “Occult
    Japan” a study of Shinto trances, published in 1894, he did not like
    at all. It struck him only “as a mood of the man, an ugly
    supercilious one, verging on the wickedness of a wish to hurt—there
    was in ‘The Soul of the Far East’ an exquisite approach to playful
    tenderness—utterly banished from ‘Occult Japan.’” _Id._, pp. 204,
    208. By this time Hearn seems to have come to resent criticism of
    the Japanese.

[9]The exact elevation proved to be 12,611.

[10]These discoveries have since been doubted.

[11]The theory of the gradual loss of water is very doubtful, but
    Percival’s main conclusions depend on the present aridity of the
    planet, not on its assumed history.

[12]In a lecture shortly before his death he said: “Where Schiaparelli
    discovered 140, between 700 and 800 have been detected at
    Flagstaff.”

[13]Thereafter the equipment of the Observatory was steadily
    enlarged—notably by a 42-inch reflector in 1909—until now there are
    five domes, and much auxiliary apparatus.

[14]Vol. 19, No. 218.

[15]Percival’s statement of this may be found also in “Mars as the Abode
    of Life,” Chapter III.

[16]Their existence was proved, although the grain of the best plates is
    too coarse to distinguish between sharp lines and diffuse bands.

[17]While written in the third person the words are clearly his own.

[18]His determination of the Martian temperature has since been very
    closely verified.

[19]In a letter to Dr. V. M. Slipher on Oct. 4, 1902 he writes:

    “There has come into my head a new way for detecting the spectral
    lines due to a planet’s own atmospheric absorption, and I beg you
    will apply it to Mars so soon as the Moon shall be in position to
    make a comparison spectrum.

    “It is this. At quadrature of an exterior planet we are travelling
    toward that planet at the rate of 18.5 miles a second and we are
    carrying of course our own atmosphere with us. Our motion shortens
    all the wave-lengths sent us from the planet, including those which
    have suffered absorption in _its_ atmosphere. When the waves reach
    _our_ atmosphere those with a suitable wavelength are absorbed by it
    and these wave-lengths are unaffected by our motion since it is at
    rest as regards us. Even were the two atmospheres alike the absorbed
    wave-lengths reaching us would thus be different since the one set,
    the planet’s, have been shifted by our motion toward it while the
    other set, our own, are such as they would be at rest. We thus have
    a criterion for differentiating the two. And the difference should
    be perceptible in your photographs. For the shift of Jupiter’s lines
    due to rotation is such as 8. × 2. = 16 miles a second produces,
    which is less than 18.5 and about what you will get now.”

[20]So far as the shooting stars are concerned this opinion was based
    upon their velocities, which have since been found in many cases to
    be greater than was then supposed.

[21]Opic has recently shown that the sun’s effective domain is even
    larger.

[22]Later observations seem to show that Mercury’s periods of rotation
    and revolution are not the same, but nearly so.

[23]It now appears very improbable that these are real comet families.

[24]Recent results indicate that these are much smaller, and sometimes
    move faster, than was formerly believed.

[25]This theory, though generally held till 1930, has apparently been
    disproved by Jeffries.

[26]The periods of revolution and rotation have since appeared not to be
    exactly the same.

[27]Radiometric measures of late years show the outer surface of Jupiter
    to be at a very low temperature.

[28]As these thickenings, which he called tores, were not perceived the
    next time the rings were seen edgewise—although probably there—it is
    needless to dwell more upon them.

[29]By continued, and quite recent, study at Flagstaff the content of
    this gas has been found to be for Jupiter and Saturn one half, for
    Uranus five times and for Neptune twenty-five times the amount of
    the atmosphere of the Earth.

    A reader who seeks to know more of the later theories of the Solar
    System may find them in the book with that name by Russell, Dugan
    and Stewart.

[30]Since he wrote, the discovery of radio-active substances has given
    rise to a wholly new crop of theories about the early geologic
    processes in the Earth’s crust.

[31]It is now practically certain that a dark star would be of very high
    density and small size, which would make the warning before the
    catastrophe still shorter.

[32]The discussion was continued in the press, Percival’s main argument
    being in his article in the _Astrophysical Journal_ for October,
    1907. Among those who claimed that the canals were optical illusions
    was Mr. Douglass after his connection with the Observatory had
    ceased; although he had previously drawn many of them, and himself
    discovered those in the darker regions.

[33]In _Popular Science Monthly_, for September, 1907, Mr. Agassiz told
    his experience in observing at Flagstaff, and why the appearance of
    canals cannot be due to optical or visual illusions.

[34]The Director’s house was commonly known as “The Baronial Mansion.”

[35]Memoirs of the Lowell Observatory, Vol. I, No. II.

[36]Bulletin No. 32.

[37]In a recent letter from the Observatory Mr. E. C. Slipher describes
    a great white spot that appeared on the equator of Saturn in 1933.
    It behaved as of hot matter flung up from the interior, and after
    two or three days spread itself towards the East in the direction of
    the planet’s rotation. His explanation is that the level from which
    this matter came is revolving faster than the atmospheric shell, the
    new material coming to the visible surface constantly more and more
    in advance of the original spot—a confirmation of Percival’s
    calculations.

[38]Vol. XIV, No. 1.

[39]“The Evolution of Worlds,” p. 118 and _seq._

[40]Adams, “Explanation of the Motion of Uranus,” 1846.

[41]Proc. Amer. Acad., Vol. 1, p. 64.

[42]Proc. Amer. Acad., Vol. 1, p. 65 _et seq._

[43]Proc. Amer. Acad., Vol. 1, p. 144.

[44]Proc. Amer. Acad., Vol. 1, p. 332.

[45]Observatory “Memoir on a Trans-Neptunian Planet.”

[46]Much of the following account is taken from “Searching Out Pluto” by
    Roger Lowell Putnam and Dr. V. M. Slipher in the _Scientific
    Monthly_ for June, 1932, by whose courtesy it is used.

[47]515 asteroids and 700 variable stars were there disclosed.

[48]After X had been discovered two very weak images of it were found on
    photographic plates made in 1915—the year he published his Memoir.

[49]This figure slightly changed for later observations is on the
    opposite page.

[50]Dr. A. C. D. Crommelin, the highest authority in England on such
    matters, had expressed the same conclusion; and the Royal
    Astronomical Society had cabled its felicitations on the discovery.
    Professor Russell’s latest views may be found in  _infra_.

[51]The non-expert reader must remember that the mass and the size—still
    more the apparent size—are very different things, and the mass is
    the only one that could be found by calculation, for this alone
    affects the attraction, which at such a distance is quite
    independent of the density and hence of the size. Moreover, the
    apparent size depends also upon the extent to which the surface
    reflects the light of the sun—technically termed the planet’s
    albedo—a matter that has no relation to the perturbation of another
    body.

[52]“The Astronomical Romance of Pluto”—Professor A. O.
    Leuschner—Publications of _The Astronomical Society of the Pacific_,
    August, 1932.

[53]See page 181 _supra_.




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