Biography of Percival Lowell

by A. Lawrence Lowell

“Upon the melting of its polar cap, and the transference of the water thus annually set free to go its rounds, seem to depend all the seasonal phenomena on the surface of the planet.

“The observations upon which this deduction is based extend over a period of nearly six months, from the last day of May to the 22d of November. They cover the regions from the south pole to about latitude forty north. That changes analogous to those recorded, differing, however, in details, occur six Martian months later in the planet’s northern hemisphere, is proved by what Schiaparelli has seen.” In order that the reader may not be confused, and wonder why the changes at the north pole do not begin shortly after those in the southern hemisphere are over, he must remember that the Martian year has 687 days, and is thus nearly twice as long as ours, or in other words that the period of these observations covered only about four months in Mars.

“So soon as the melting of the snow was well under way, long straits, of deeper tint than their surroundings, made their appearance in the midst of the dark areas,” although the dark areas were then at their darkest. “For some time the dark areas continued largely unchanged in appearance; that is, during the earlier and most extensive melting of the snow-cap. After this their history became one long chronicle of fading out. Their lighter parts grew lighter, and their darker ones less dark. For, to start with, they were made up of many tints; various shades of blue-green interspersed with glints of orange-yellow.... Toward the end of October, a strange, and, for observational purposes, a distressing phenomenon took place. What remained of the more southern dark regions showed a desire to vanish, so completely did those regions proceed to fade in tint throughout.” He points out that such a change is inexplicable if the dark areas were water, for there was no place for it to go to. “But if, instead of being due to water, the blue-green tint had been due to leaves and grasses, just such a fading out as was observed should have taken place as autumn came on, and that without proportionate increase of green elsewhere; for the great continental areas, being desert, are incapable of supporting vegetation, and therefore of turning green.” By the continental areas he meant the barren regions, formerly thought to stand out from seas in contrast with the darker ones supposed to be water.

“Thus we see that several independent phenomena all agree to show that the blue-green regions of Mars are not water, but, generally at least, areas of vegetation; from which it follows that Mars is very badly off for water, and that the planet is dependent on the melting of its polar snows for practically its whole supply.

“Such scarcity of water on Mars is just what theory would lead us to expect. Mars is a smaller planet than the Earth, and therefore is relatively more advanced in his evolutionary career.” And as a planet grows old its water retreats through cracks and caverns into its interior. The so-called seas were, he thinks, once such, and “are still the lowest portions of the planet, and therefore stand to receive what scant water may yet travel over the surface.” With this agrees the fact that the divisions between the dark and light areas run south-east north-west; as they would if made by currents in water flowing from the pole toward the equator.

“Now, if a planet were at any stage of its career able to support life, it is probable that a diminishing water supply would be the beginning of the end of that life, for the air would outlast the available water.[11]...

“Mars is, apparently, in this distressing plight at the present moment, the signs being that its water supply is now exceedingly low. If, therefore, the planet possess inhabitants, there is but one course open to them in order to support life. Irrigation, and upon as vast a scale as possible, must be the all-engrossing Martian pursuit....

“At this point in our inquiry, when direct deduction from the general physical phenomena observable on the planet’s surface shows that, were there inhabitants there, a system of irrigation would be an all-essential of their existence, the telescope presents us with perhaps the most startling discovery of modern times,—the so-called canals of Mars.”

He then takes up these so-called canals or lines which start from the edge of the blue-green regions, proceed directly to what seem centres in the middle of the ochre areas, where they meet other lines that come, he says, “with apparently a like determinate intent. And this state of things is not confined to any one part of the planet, but takes place all over the reddish-ochre regions,” that is the arid belt of the planet. “Plotting upon a globe betrays them to be arcs of great circles almost invariably, even the few outstanding exceptions seeming to be but polygonal combinations of the same.” These two facts, that the lines are great circles, or the shortest distance between points on the surface of the planet, and that several of them often meet at the same place, must be borne in mind, because they are essential elements in his argument that they are the result of an intelligent plan.

The lines are of enormous length, the shortest being 250 miles, and the longest 3,540, and at times three, four, five, and even seven come together at one spot. By them the whole region is cut up, and how many there may be cannot now, he says, be determined, for the better the air at the observatory the more of them become visible. At Flagstaff they detected 183, seen from once to 127 times, and there were in the aggregate 3,240 records made of them.[12]