MARS AS THE ABODE OF LIFE BY PERCIVAL LOWELL, A.B., LL.D. AUTHOR OF "MARS AND ITS CANaLS," ETC. director of the observatory at flagstaff, arizona; non-resident professor of astronomy at the massachusetts institute of technology; fellow of the american academy of arts and sciences: membre de la soc1ete astronomique de france: member of the astronomical and astro- physical society of america: mitglied der astronomische ge- sellschaft; membre db la societe belge d'astronomie; honorary member of the sociedad astronomica de mex ico; janssen medalist of the societe astronomique de france, mm, for researches on mars; etc., etc. ILLUSTRATED 3?efa gorit THE MACMILLAN COMPANY 1908 All rights reserved Copyright, 1908, Bv THE MACMILLAN COMPANY. Set up and electrotyped. Published December, 1908. 371220 ,.,.;«. NortoooB jirraa J. 8. Gushing Co. — Berwick & Smith Co. Norwood, Mass., U.8.a. JkflCROFILM AVAILABLE MY BROTHER PROFESSOR ABBOTT LAWRENCE LOWELL, LL.D. WHO AS TRUSTEE OF THE LOWELL INSTITUTE PROPOSED THESE LECTURES THIS PRESENTATION OF THEM IS AFFECTIONATELY INSCRIBED PREFACE In 1906 Professor Lowell was asked by the trustee of the Lowell Institute to deliver a course of lectures there upon the planet Mars. Eleven years had elapsed since, at the invitation of the former trustee, he had done the like. When the time came for their delivery unusual interest was manifested, the course proving the most thronged of any ever given before the Insti tute. So great was the demand for seats that the hall could not contain the crowd, and the lectures had to be repeated in the afternoons, to audiences almost as large. The eight lectures were then published, with slight changes, in six papers in the Century Magazine, and were subsequently wanted by Macmillan and Com pany for issuance in book form. Though dealing specifically with Mars, the theme of the lectures was that of planetary evolution in gen eral, 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 re search into the genesis and development of what we call a world ; not the mere aggregating of matter, but vii viii PREFACE what that aggregation inevitably brings forth. The subject which links the Nebular Hypothesis to the Darwinian theory, bridging the evolutionary gap be tween the two, he has called planetology, thus desig nating 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. The object of the founding of the Observatory at Flagstaff was the study of the planets of our solar system ; a subject it has now for fourteen years made its specialty, the site, chosen for the purpose, en abling it to prosecute this study to more advantage than is possible at any other observatory at present. From the data thus collected, light has been thrown upon the evolution of the planets as worlds, resulting in a thesis of which the present book is a preliminary presentation. 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. Their truth can only be adequately appreciated by those able to follow the physical and mathematical processes involved, and for this the gen eral reader has not the necessary technical education. Yet there are many, professional and unprofessional PREFACE ix alike, capable of comprehending provided the steps are made sufficiently explicit. It has seemed, there fore, worth the trying to attempt to write for both classes of the community in a single volume. To do this, the general text has been printed complete in itself, while the demonstrations of the several steps have been collected in a part by themselves with refer ence to the places in the text where they severally should occur. All illustrations of the planet Mars are by Professor Lowell. May, 1908. s CONTENTS rAOE Foreword I PART I CHAfTEK I. The Genesis of a World .... 3 Catastrophic origin ...... 3 Meteorites ....... 4 Meteorite worship ...... 4 Meteoric constitution of solar system . 5 AnalogyAmountTheSubstances meteorites ofof vary heatcataclysm gravitate withdepends heat to newtogether,on and the stars pressure mass generating (Novae) of the body heat 67 8 Mass the fundamental factor .... 9 Cooling ....... 9 Life-history depends on size .... ii Planetologic eras ..... 1 1 GeologicPresent aspects part of of planetology the planets .... our guide . 12 •3 Landscape the result of cooling •4 Mountains in proportion to mass 'S 1 Volcanic phenomena ..... 16 Relative roughness of Earth, Moon, and Mars . 16 Mountains absent on Mars .... 16 Slant illumination ..... 17 Importance to astronomers .... «7 Applied to Mars ..... 18 Not indicative of mountains .... 21 Two or three thousand feet limit of elevation on Mars 22 XI xu CONTENTS PAGE InternalDarwinianConfirmedContinentalProbable heat comparative theoryby and of lunar the oceanic of three surface lunar internal areas bodies origin . heatformed of earth and 23 26 26 Transition Mars 27 28 TheirTrue Martian distribution message determined . 28 3° TheirTheirEarth's relativeflooring oceanic size attests basins on it different permanent planets . 3° 32 33 II. The Evolution of Life 35 The origin of organic life . 35 Life an inevitable phase of planetary evolution 37 Water essential to life ... 39 Seas the earliest home of mundane life 42 Uniformity of paleozoic fossils . 45 Carboniferous plant life 46 Light less and heat more then than now . 48 Effect on the earth .... 49 Earth itself responsible for paleozoic heat . 5° Earth, not sun, the motive force in evolution in the paleozoic era . 52 -~ A once cloudy Mars ... 52 Life outgrows the sea . 53 Effect of environment upon evolution 54 Deep-sea life thought impossible fifty years ago 57 Extinction of light 57 Deep-sea life . 58 Blindness .... 60 Phosphorescent organs . 61 Lesson of the fishing fishes 61 Cosmic character of life 64 III. The Sun Dominant 70 70 CONTENTS xm The sun asserts itself . 7i Mars betrays the same evolution 73 The thin atmosphere of Mars 78 - - The polar caps of Mars 80 The question of temperature on Mars 83 _^-The clear skies of Mars 85 Summer and winter temperatures . 87 Aspect of Mars corroborative 89 - Summer the life season . 90 ~~Zones of vegetation of the San Francisco Mountains 93 Summer temperature determinative of life 95 Plateaux hotter than peaks at a like elevatic 98 Water-vapor in the air of Mars 103 Vegetation of Mars 106 Mode of manifestation of life 107 IV. Mars and the Future of the Eabjh 1 1 1 - Mars has lost its oceans 112 -The oceans of earth are disappearing 118 Gain of land in North America and Europe 119 Lowering of the sea-level 121 Inland seas .... Terrestriality succeeds terraqueousness 123 Deserts ..... 124 The petrified forest of Arizona 126 Egypt and Carthage 128 Palestine ..... 1 29 Subtropical regions chiefly affected . 129 - Planetary change far advanced on Mars ■3' The opaline tints of Mars . '34 How the earth will follow Mars »35 Water present in the Martian atmosphere 136 The surface of Mars a waterless world 142 A high type of life probable on Mars 142 The probability of life on Mars at the present time 144 XIV CONTENTS The Canals and Oases of Mars . .146 SchiaparelliLinesCanalsCanalsOases are superposedin straightdark . and regions the . over canals ... main ....features .... ..... .... .146.148.152.155.156 TheSearchNewWidthArea canals ofmethod fordiffers zones clew are offor subject to research. different decipherment to. change doubles .. ..... .... ..... .168.163.167.160 1 74 TheQuickeningQuickeningMelting earth first as ofstarts necessary witnessed canals at polar according on from cap Mars space to latitude ... ... .... ..176.178 1175 79 Speed of spread of vegetation . .181 VI. Proofs of Life on Mars . .184 DiscoveryReview of of the celestial natural truths chain similarof evidence to detective . .work ..186 184 Aspect of Mars corroborates principles of planetary evolution . .186 Canals Animal confront life disclosed the observer only by . mind . .. .188 Not rivers . .191 Not cracks . .191 Other natural explanations prove impossible . 192 Oases equally inexplicable . .194 Artificiality suggests itself . .195 Great-circle character of the canals . .196 Circularity of oases . .197 ItsMars'Note locomotion of surface water a explainedruns level through surface the .. action .. ... ... .200.199.197 Gravity incapable of water transference . .201 Organisms evolve as a planet ages .... 205 CONTENTS XV CHAPTER PAGE One species supplants all others 206 To die of thirst . 207 End foreseen 208 Further phenomena 21 I Speculation excluded 2I4 Our life not unique 2I5 Martian life nearing its end 216 PART Notes II 1 . On Moment of Momentum .... 219 2. The Connection of Meteorites with the Solar System 2ZO 3. The Heat developed by Planetary Contraction 225 4. The Heights of Mountains on the Moon 229 5. Heat acquired by the Moon . 23O 6. Surface Heat of Mars 7. The Boiling-point of Water on Mars . 231 8. The Paleozoic Sun .... 232 9. Effect on the Earth of the Supposed Paleozoic Sun 233 10. On the Influence upon the Climate of Carbon Dioxide in the Air .... 236 1 1 . Atmosphere of Mars 238 12. The Mean Temperature of Mars 240 13. A Dust Storm on Mars 256 14. Mars on the Cause of an Ice-age 265 15. Tidal Effects .... 270 1 6. On the Visibility of Fine Lines . 271 17. Canals of Mars 279 18. Position of the Axis of Mars 280 Index ...... 283 LIST OF ILLUSTRATIONS PLATES I. On the Road to the Observatory Frontispiece orrosiTK pace II.