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17 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; for though the general system is, curiously, one for the whole planet, the particular character of different parts of the surface alters the action there to some extent. For an appreciation of the meaning of the changes, it is to be borne in mind throughout that the vernal equinox of Mars' southern hemisphere occurred on April 17, 1894; the summer solstice of the same hemisphere on August 31; and its autumnal equinox on m4 a o10ne On the 31st of May, therefore, it was toward the end of April on Mars. The south polar cap was, as we have seen, very large, and the polar sea in proportion. That the polar sea was the darkest and the bluest marking on the disc implies that it was, at all events, the deepest body of water on the planet, whether the other so-called seas were seas or not. This polar sea plays deus ex machina to all that follows. 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. I did not see them come, but as I afterward saw them go, it is evident that they must have come. They were already there on the last day of May. The most conspicuous of them lay between Noachis and Hellas, in the Mare Australe. It began in the great polar bay, and thence traversed the Mare Erythraeum to the Hour-Glass Sea (Syrtis Major). The next most conspicuous one started in the other bay, and came down between Hellas and Ausonia. Although these straits were distinguishably darker than the seas through which they passed, the seas themselves were then at their darkest. The fact that these straits traversed the seas suffices to raise a second doubt as to the genuineness of seas; the first suspicion as to their true character coming from their being a little off color,--not so blue, that is, as what we practically know to be water, the polar sea, although even that must be anything but deep. It will appear later that in all probability the straits too are impostors, and that we see is in neither case water. The appearance of things at this initial stage of the Martian Nile-like inundation last June was most destructive to modern maps of Mars, for all the markings between the south polar cap and the continental coast-line seemed with one consent to have as nearly as might be obliterated themselves. It was impossible to fix any definite boundaries to the south temperate chain of islands, so indistinguishably did the light areas and the dark ones merge into each other. What was still more striking, the curious peninsulas which connect the continent with the chain of islands to the south of it, and form so singular a feature of the planet's geography, were invisible. One continuous belt of blue-green stretched from the Syrtis Major to the on ee eo See February 7, 1895. Columns of Hercules.