I wish to express my obligations to Professor Percival Lowell for the privileges of his observatory, for many of the illustrations in this book, and for his unbounded hospitality during my visit to Flagstaff. I am also deeply indebted to Mr. Russell Robb for valuable assistance during the preparation of the manuscript.

E. S. M.

Salem, Massachusetts,
October, 1906.

[CONTENTS]

Page
I.Introduction[1]
II.Immeasurable Distances of Space[7]
III.Other Worlds Inhabited[14]
IV.Lowell's Book on Mars[31]
V.Testimony of Astronomers[51]
VI.The Study of Planetary Markings[70]
VII.Difficulties of Seeing[79]
VIII.Variation in Drawing[94]
IX.Theories Regarding the Canals[100]
X.Comments and Criticism[125]
XI.Atmosphere and Moisture[134]
XII.Notes on Irrigation[141]
XIII.Variety of Conditions under which Life Exists[147]
XIV.My Own Work[158]
XV.What the Martians Might Say of Us[166]
XVI.Schiaparelli, Lowell, Perrotin, Thollon[172]
XVII.Last Words[180]
Index[189]

[LIST OF ILLUSTRATIONS]

Lowell's Globe of Mars[Frontispiece]
Fig. 1. Planisphere of EarthPage[61]
PLATES
I.Tobacco Cultivation under Cloth, Porto RicoPage[50]
II.Drawings of Solar Corona"[96]
III.Chinese Bowl, showing Crackle"[107]
IV.Mud Cracks on Shore of Roger's Lake, Arizona"[108]
V.Natural Lines, Cracks, Fissures, etc."[112]
VI.Artificial Lines, Railways, Streets, Canals, etc."[113]
VII.Dome of Lowell Observatory, Flagstaff, Arizona"[158]
VIII.Twenty-four Inch Telescope, Lowell Observatory"[160]
IX.Drawings of Canals of Mars by the Author"[162]
PORTRAITS
Giovanni Virginio SchiaparelliPage[172]
Percival Lowell"[174]
Henri Perrotin"[176]
M. Thollon"[178]

Life not wholly unlike that on the earth may therefore exist upon Mars for anything we know to the contrary.