Page:Popular Science Monthly Volume 35.djvu/57

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structed a chart of Mars, which was published in his most famous book, "Other Worlds than Ours," and which is reproduced with this article. The most hasty comparison of this chart with the drawings of Cassini and Herschel shows that an enormous advance PSM V35 D057 Old drawings of mars.jpgOld Drawings of Mars. had been made since the time of the latter, incomparably greater, in fact, than had been accomplished in the hundred and more years that elapsed between Cassini and Herschel. Yet if we should place any single one of Dawes's drawings side by side with those of the old observers, the difference would not appear by any means so striking, for, the reader must recollect, Mr. Proctor's chart was constructed by inspecting and comparing twenty-seven of Dawes's sketches, representing the planet at different periods of its rotation, so that all sides of it were successively viewed in the best position for observation. If we had an equally numerous series of Cassini's, or preferably of Herschel's sketches, made in a similar manner, we should probably be able to construct from them a chart which, while it certainly would be greatly inferior to Proctor's in its details, would nevertheless make it clear that the earlier observers saw many of the principal markings that are shown in the more modern map.

Still more detailed charts of Mars followed that of Mr. Proctor, notably those of M. Flammarion, and Mr. Green, the latter being a very beautiful work based upon a series of splendid drawings made by Mr. Green in the island of Madeira. But no very considerable advance was made in areography, as the geography of Mars has been called, until Signor Schiaparelli published the results of his surprising observations made during the very favorable opposition of Mars in 1877. Although Schiaparelli has repeated these observations again and again, and they have been confirmed, in part at least, by several able observers, there is a disposition in some quarters to cast doubt upon them, and to ascribe them to the effects of optical illusion or some other hallucination. Considering the wonderful character of these observations, and the immense advance that they constitute in the study of the surface of Mars, there is, perhaps, the shadow of an excuse for some incredulity about them. Yet I think the reader will be