“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 deg. north to latitude 0 deg., 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).

I think my readers will agree with me that this whole argument is one of the most curious ever put forth seriously by an eminent man of science.  Because the polar compression of Mars is about what calculation shows it ought to be in accordance with its rate of rotation, its surface is in a state of ‘fluid equilibrium,’ and must therefore be absolutely level throughout.  But the polar compression of the earth equally agrees with calculation; therefore its surface is also in ‘fluid equilibrium’; therefore it also ought to be as perfectly level on land as it is on the ocean surface!  But as we know this is very far from being the case, why must it be so in Mars?  Are we to suppose Mars to have been formed in some totally different way from other planets, and that there neither is nor ever has been any reaction between its interior and exterior forces?  Again, the assumption of perfect flatness is directly