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21 slowly upwards towards the pole in all other respects. Then suddenly some night he finds that it has slipped bodily down, to begin again its Sisyphus-like, inconclusive spiral climb. Often as this rhomb-line must have been noticed, no explanation of it has ever, to my knowledge, been given. Yet so singular an arrangement points to something other than chance. Suspicion of its non-fortuitous character is strengthened when it is scanned through a bigger glass. Increase of aperture discloses details that help explain its significance. With sufficient telescopic power, the continuity of the dark belt is seen to be broken by a series of parallel peninsulas or semi-peninsulas that jut out from the lower edge of the belt, all running with one accord in a southeasterly direction, and dividing the belt into a similar series of parallel dark areas. Such oblong areas are the Mare Tyrrhenum, the Mare Cimmerium, the Mare Sirenum, and those unnamed straits that stretch southeasterly from the Aurorae Sinus, and Margaritifer Sinus, and the Sabaeus Sinus. The islands and peninsulas trending in the same direction are Ausonia, Hesperia, Cimmeria, Atlantis, Pyrrhae Regio, Deucalionis Regio, and the two causeways from the Fastigium Aryn and Hammonis Cornu. It will further be noticed that these areas lie more nearly north and south as they lie nearer the pole, and curve in general to the west as they ne re eee ee With this fact noted, let us return to the water formed by the melting of the ice-cap, at the time it is produced around the south pole. We may be sure it would not stay there long. No sooner liberated from its winter fetters than it would begin, under the pull of gravity, to run toward the equator. The reason why it would flow away from the pole is that it would find itself in unstable equilibrium where it was. Successive depositions of frost would have piled up a mound of ice which, so long as it remained solid, cohesion would keep in that unnatural position, but the moment it changed to a liquid this would flow out on all sides, seeking its level. Once started, its own withdrawal would cause the centre of gravity to shift away from the pole, and this would pull the particles of the water yet more toward the equator. Each particle would start due north; but its course would not continue in that direction, for at each mile it traveled it would find itself in a lower latitude, where, owing to the rotation of the planet, the surface would be whirling faster toward the east, inasmuch as a point on the equator has to get over much more space in twenty-four hours than one nearer the pole. In short, supposing there was no friction, the surface would be constantly slipping away from under the particle toward the east. As a result, the northerly motion of the particle would be continually changing with regard to the surface into a more and more westerly one. If the surface were not frictionless, friction would somewhat reduce the westerly component, but could never wholly destroy it without ey es eee We see, therefore, that any body, whether solid, liquid, or gaseous, must, in traveling away from the pole of a sphere or spheroid, necessarily deviate to the west as it goes on, if the spheroid itself revolve, as Mars does, in the opposite direction. This inevitable trend induced in anything flowing from the pole to the equator is precisely the one that we notice stereotyped so conspicuously in the Martian south temperate approach the equator. stopping this particle.