“Just a moment, please,” put in Mrs. Mundy. “What are the oases?”
Joshua assumed a pedagogic attitude.
“The oases,” he explained, “are probably round or oval lakes, fed by the irrigating water courses, probably serving as reservoirs or distributing centers, and forming centers of civilization—cities or urbanlike farming communities. They average about three hundred miles in diameter. The northern hemisphere of Mars is mostly desert, but crossed by canals as they travel toward the regions where vegetation is grown. Some of the canals are as much as eighty miles in breadth—and average about thirty miles. The word canals includes water and vegetation.
“During the winter months the canals are so faint as to be invisible in most cases. Beginning at the snow line, the canals assume a blue-green color—a sort of robin’s egg blue—which eventually extends to the entire system. With the approach of autumn the color changes, and instead of green the canals become a reddish-ochre, or russet, remaining this color until winter, when they begin to grow gradually fainter, and sometimes disappear entirely.
“Now, to return to our theory of irrigation, the irrigation of an entire planet, as seems to me to be the case on Mars, certainly would tax the mathematical and engineering abilities of experts on our own earth. And this wonderful system of irrigation canals—one of them over three thousand miles in length—is not the pipe dream of some over-imaginative star gazer. Many of the canals have been recorded repeatedly on the one hundred thousand photographs made at the Lowell Observatory during the past fifteen years.
“Well, now, ye thirsters for learning who have come to the fountain head of wisdom, let us assume that Mars is inhabited. Let us say, further, that her inhabitants are intelligent beings—far more intelligent than we, as proved by their amazing system of canals. And let us adopt the belief that these super-intelligent Martians are striving desperately to communicate with us. They may have discovered radio, and the wireless waves received by Marconi may indicate an attempt to get in touch with us. But we don’t know for sure that those waves came from Mars or any other planet. What we do know, however, is that the Martians excel in engineering; and we have no proof that they excel us in anything else.
“So then, since we understand engineering after a fashion, isn’t it logical to harbor the hypothesis that the Martians may resort to their knowledge of engineering to establish communication with us?
“Communication by means of wireless waves may be all right for Marconi and others, but it’s out of my line. I’m a telescope fiend, and I’m hoping to prove that Mars is trying to communicate with us through the medium of sight instead of sound. So during my last few years in the House of Refuge, and even while I was tramping over the country with my friend The Whimperer, I spent many nights while Mars was in opposition to the earth in looking for some physical demonstration on the part of the Martian engineers.
“There is but one universal language, and that is mathematics. And it is my belief that the Martians are trying to communicate with the earth by excavating canals which will, when completed, form a geometrical figure that could not possibly be misinterpreted as having been fashioned by natural causes. Canals could be constructed for the purpose of letting us know that the Martians are intelligent beings, and at the same time these same canals could serve them as waterways for irrigating purposes.
“And I think—I’m almost sure—that such a figure, on a colossal scale, is being made for us to see. I think that I have seen it growing, and it was that one fleeting glimpse that gave me my theory. After that I was constantly on the lookout, until The Whimperer stole my telescope, but saw nothing after that first unusual observation. You perhaps do not understand fully that, even though such a figure were constructed on an enormous scale, it might become visible for only a moment or two at one time, even under the most favorable atmospheric conditions. Even established astronomers, using the world’s greatest telescopes, might miss that rare, exceptional moment. They might be looking in the wrong place, you know. And, besides, the higher magnifying powers can seldom be used advantageously in observations of the Martian surface. If a keen-eyed, tireless observer has a small telescope favorably situated he may be the first to glimpse such a signal when the rare moment arrives. For the canals of Mars may be looked for in vain, night after night, with mighty telescopes, and yet remain invisible. Then suddenly comes a moment of exceptionally good seeing, as telescopists call it, and the fine, hairlike lines stand forth in all their fascinating geometrical symmetry—for one brief moment only! And what if I, Joshua Cole, inmate of a reform school for over six long years, tramp, construction stiff, should be on watch on Spyglass Mountain when that moment comes!... I thank you for your kind attention!”