Abstract
THE MARKINGS ON MARS.—M. Perrotin, in a more recent communication to the Paris Academy of Sciences, states that the district of Libya, the disappearance of which he had recorded a week or two earlier (NATURE, vol. xxxviii. p. 185), has undergone a further change, the “sea” which had so recently covered it having retreated again for the most part, so that the present appearance of the district is intermediate between that which it recently presented and that under which it was seen in 1886. Of the canals M. Perrotin has noticed four, three of which are double, which, starting from the “seas” of the southern hemisphere near the equator, and following a nearly meridional course, extend right up to the north polar ice cap, being traceable across the “seas” which immediately surround the latter. No other observer as yet seems to have traced these canals for such a distance, and across “seas” as well as continents. This observation renders their true character more puzzling than ever, and seems effectually to dispose both of M. Fizeau's just published theory, which explains them by the analogy of the rifts in terrestrial glaciers, Mars being assumed to be in a glacial condition, and of that of Mr. Proctor, who ascribes them to the varying appearances of the Martial rivers when clearly seen or partly veiled by local mists. More detailed observations of these strange markings are needed, and it is to be much desired that as many as possible of actual drawings made at the telescope should be published. It is possible that the comparison of sketches made with different observers and with different apertures, would throw much light on the subject; if, for instance, the appearances were partly optical and due to some effect of diffraction, it would soon become apparent.
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Our Astronomical Column . Nature 38, 258 (1888). https://doi.org/10.1038/038258a0
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DOI: https://doi.org/10.1038/038258a0