"A body of planetary size, if unrotating, becomes a sphere, except for solar tidal deformation; if rotating, it takes on a spheroidal form exactly expressive, so far as observation goes, of the so-called centrifugal force at work. Mars presents such a figure, being flattened out to correspond to its axial rotation. Its surface therefore is in fluid equilibrium, or, in other words, a particle of liquid at any point of its surface at the present time would stay where it was devoid of inclination to move elsewhere. Now the water which quickens the verdure of the canals moves from the pole down to the equator as the season advances. This it does then irrespective of gravity. No natural force propels it, and the inference is forthright and inevitable that it is artificially helped to its end. There seems to be no escape from this deduction. Water only flows downhill, and there is no such thing as downhill on a surface already in fluid equilibrium. A few canals might presumably be so situated that their flow could, by inequality of terrane, lie equatorward, but not all....Now it is not in particular but by general consent that the canal-system of Mars develops from pole to equator. From the respective times at which the minima take place, it appears that the canal quickening occupies fifty-two days, as evidenced by the successive vegetal darkenings, to descend from latitude 72° north to latitude 0°, a journey of 2650 miles. This gives for the water a speed of fifty-one miles a day, or 2.1 miles an hour. The rate of progression is remarkably uniform, and this abets the deduction as to assisted transference. But the fact is more unnatural yet. The growth pays no regard to the equator, but proceeds across it as if it did not exist into the planet's other hemisphere. Here is something still more telling than travel to this point. For even if we suppose, for the sake of argument, that natural forces took the water down to the equator, their action must there be certainly reversed, and the equator prove a dead-line, to pass which were impossible" (pp. 374-5).