“The surface of the planet to be very curiously meshed by a fine network of lines and spots.
“Now if one considers first the appearance of this network of lines and spots, and then its regular behaviour, he will note that its geometrism precludes its causation on such a scale by any natural process and, on the other hand, that such is precisely the aspect which an artificial irrigating system, dependent upon the melting of the polar snows, would assume. Since water is only to be had at the time it is there unlocked, and since for any organic life it must be got, it would be by tapping the disintegrated cap, and only so, that it could be obtained. If Mars be inhabited, therefore, it is precisely such a curious system we should expect to see, and only by such explanation does it seem possible to account for the facts.
“These lines are the so-called canals of Mars. It is not supposed that what we see is the conduit itself. On the contrary, the behaviour of these lines indicates that what we are looking at is vegetation. Now, vegetation can only be induced by a water-supply. What we see resembles the yearly inundation of the Nile, of which to a spectator in space the river itself might be too narrow to be seen, and only the verdured country on its banks be visible. This is what we suppose to be the case with Mars. However the water be conducted, whether in covered conduits, which seems probable, or not, science is not able to state, but the effects of it are so palpable and so exactly in accord with what such a system of irrigation would show, that we are compelled to believe that such is indeed its vera causa.”
Beside the bulky Memoirs in which Prof. Lowell has published the scientific results obtained at his observatory at Flagstaff, and papers and articles appearing in various scientific journals, he has brought out three books of a more popular character: “Mars”; “Mars and its Canals”; and “Mars as the Abode of Life.” In these he shows that to the assiduity of the astronomer he adds the missionary’s zeal and eagerness for converts as he pleads most skilfully for the acceptance of his chosen doctrine of the presence of men on Mars. In the last of the three books mentioned, he deals directly with “Proofs of Life on Mars.” The presence of vegetation may be inferred from seasonal changes of tint, just as an observer on the Moon might with the naked eye watch effects on the Earth. But though “vegetable life could thus reveal itself directly, animal life could not. Not by its body but by its mind would it be known. Across the gulf of space it could be recognized only by the imprint it had made on the face of Mars.”
“Confronting the observer are lines and spots that but impress him the more, as his study goes on, with their non-natural look. So uncommonly regular are they, and on such a scale as to raise suspicions whether they can be by nature regularly produced” (p. 188).
“... Unnatural regularity, the observations showed, betrays itself in everything to do with the lines: in their surprising straightness, their amazing uniformity throughout, their exceeding tenuity, and their immense length” (p. 189).
“As a planet ages, its surface water grows scarce. Its oceans in time dry up, its rivers cease to flow, its lakes evaporate (p. 203).... Now, in the struggle for existence, water must be got.... Its procuring depends on the intelligence of the organisms that stand in need of it.... As a planet ages, any organisms upon it will share in its development. They must evolve with it, indeed, or perish. At first they change only, as environment offers opportunity, in a lowly, unconscious way. But, as brain develops, they rise superior to such occasioning.... The last stage in the expression of life upon a planet’s surface must be that just antecedent to its dying of thirst.... With an intelligent population this inevitable end would be long foreseen.... Both polar caps would be pressed into service in order to utilize the whole available supply and also to accommodate most easily the inhabitants of each hemisphere” (pp. 204-11).
“That intelligence should thus mutely communicate its existence to us across the far reaches of space, itself remaining hid, appeals to all that is highest and most far-reaching in man himself. More satisfactory than strange this; for in no other way could the habitation of the planet have been revealed. It simply shows again the supremacy of mind.... Thus, not only do the observations we have scanned lead us to the conclusion that Mars at this moment is inhabited, but they land us at the further one that these denizens are of an order whose acquaintance was worth the making” (p. 215).
For the moment, let us leave Prof. Lowell’s argument as he puts it. Whether we accept it or not, it remains that it is a marvellous achievement of the optician’s skill and the observer’s devotion that from a planet so small and so distant as Mars any evidence should be forthcoming at all that could bear upon the question of the existence of intelligent organisms upon its surface. But it is of the utmost significance to note that the whole question turns upon the presence of water—of water in the liquid state, of water in a sufficient quantity; and the final decision, for Mr. Lowell’s contention, or against it, must turn on that one point. The search for Life on Mars is essentially a search for Water; a search for water, not only in the present state of Mars, but in its past as well. For, without water in sufficient quantities in the past, life on Mars could not have passed through the evolutionary development necessary to its attaining its highest expression,—that where the material living organism has become the tabernacle and instrument of the conscious intelligent spirit.