Had some one asked, fifty years ago, Is the Sun composed of chemical elements with which we are familiar? Shall we ever know? the question would not have been deemed worthy of a second thought. Realizing what has been accomplished, not only regarding the constitution of the Sun, but of the most remote stars, we are encouraged to ask: Is Mars inhabited? Shall we ever know? To what groups of students are we to appeal for an answer? If we want to know the diameter of Mars, its weight, the form of its orbit, the inclination of its axis, the period of its revolution around the Sun, and its rotation period, its ephemeris and its albedo, we ask the astronomer, for he has the instruments with which to observe and measure, and the mathematical knowledge necessary to reduce the measurements. If Mars were incandescent, we should appeal to the astrophysicist for information regarding its chemical composition. If, however, we want to know the probability of Mars being the abode of life, we should appeal to one who is familiar with the conditions of life upon our own globe. If the question is asked as to the existence of intelligence on the planet, we endeavor to trace evidences of its surface markings, and their character, whether natural or artificial. Knowing how profoundly man has changed the appearance of the surface features of our own globe in the removal of vast forests, in the irrigation of enormous tracts of sterile plain, the filling up of certain areas, like Peking, Tokio, London, with material having a different reflecting surface, we are to scan the surface of Mars for similar modifications, and for an answer ask those who are familiar with physical geography, with meteorology, with geology, including the character of natural cracks or crannies, deep caÑon, or range of mountains, or any of the great cataclysms which have scarred the face of the Earth. Taking the great mass of facts as they are presented to us by astronomers, to what class are we to appeal as to the probability of life in other worlds? What class will form the most rational conclusions? Will it be the circle-squarers, perpetual-motion cranks, spiritualists, survivals of a past who believe the world is flat, those who have "anthropomorphic conceptions of the Supreme" and Hebraic conceptions of the origin of things, or will it be those who value observation and experiment, who appreciate the importance of large numbers, and who are endowed with a tithe of imagination? Most certainly the latter class.

In approaching the interpretation of the markings of Mars we should first glance at a brief historical summary of what has already been done. We should examine the testimony of those who have seen and drawn the canals; we are then better prepared to examine the records of the latest observations and the explanation of their nature. In the meantime an inquiry must be made as to whether the mathematical astronomer, after all, is best fitted to judge of the surface features of a planet. Next we should take up in the following order the evidences, which are overwhelming, that a network of lines, geodetic in their character, mark the surface of Mars. It has been claimed that these lines show the result of irrigation, and, therefore, the irrigation features of our own planet should be examined. It has been objected that many astronomers have not been able to see the markings, and consequently their existence has been doubted. It will then be proper to point out that the difficulties of seeing are very great, and that the acutest eyesight, coupled with long practice, is necessary to recognize the markings. It has been objected that the drawings of the minuter details of Mars vary with different observers. It will be necessary to show that every kind of research employing graphic representation labors under the same difficulty, and none more so than astronomy. It has been objected that there is not sufficient moisture and atmosphere in Mars to sustain life, and this must be answered by those only who are familiar with conditions affecting life on our own planet.

Various theories have been advanced, some of them physical, to explain the markings of Mars, and these must be considered, and, if possible, answered. Comments and criticism are difficult to repress, as the discoveries of Schiaparelli and the additional discoveries and deductions of Lowell have evoked discussions, which, in some instances, have been harsh and unreasonable, and, in one case, positively ridiculous. Schiaparelli has been called an impostor, and Lowell has come in for his full share of vituperation and innuendo. If this portion of the discussion is considered unparliamentary, the attitude and language of certain astronomers have provoked it.

A brief account is presented of what the author was enabled to draw of the Martian details, with a transcript of his notes made at the time of observation, and finally a little imaginary sketch is given as to how the world would look from Mars; and if similar kinds of astronomers existed there, what comments and objections they might offer as to the inhabitability of the Earth.

Such flights of the imagination are justified in that it gives one a chance to appreciate the weakness of some of the arguments urged against the idea of intelligence in Mars.

It will be objected that some of the names herein quoted are not recognized as astronomers. I can only say that in every instance I have found references to the writings and essays of those that might be objected to in the pages of the "Observatory," and other reputable astronomical journals, and in no instances accompanied by adverse comment or criticism. If astronomers?—?even the distinguished Schiaparelli?—?quote these names in scientific memoirs, I may venture to do the same in a book written for the general reader. The objection, however, has always presented itself with every controversy; it was conspicuously marked in the passionate discussions over Darwin's "Origin of Species." The intelligent laity recognized the truth of Darwin's proposition long before the zoÖlogist began to waver. Essays by the unprofessional supporting Darwin's contention were discredited because the writers were not trained naturalists. The history of invention is crowded with instances where devices and processes have been invented by men whose trades or professions were the least likely to enable them to originate such ideas.