Abstract
PARIS Academy of Sciences, Sept. 1.—M. Bertrand in the chair.—The following papers were read:—On the Aurora Borealis, by M. Faye. The author's paper related to Donati's late memoir on the same subject, in which he suggests that the passage of electro-magnetic currents from the sun to the planets is the cause of this phenomenon. M. Faye, on the other hand, deprecated the introduction of such a theory, and suggested that the effect of gravity as an agent in producing these effects may at least be probable. He suggested that motions such as are observed in the tails of comets might occur in the upper regions of our atmosphere, i.e. that excessively attenuated air might be constantly rushing from the side of the earth turned towards the sun to that turned from it, and that this motion might cause incandescence of the air, visible at the poles as auroræ.—On the Carpellary Theory as regards the Amygdalaceæ, by M. A. Trécul.—Gnomonic projection, &c., of a portion of the Sahara, by M. A. Poinel.—Study of the metallic veins of Cornwall; structure of the rich veins, and their relation to the stratigraphical arrangement of the country, by M. Moissenet.—On the Siemens coil, by M. A. Pellerio.—Observations of Planet 133 and of Borrelly's comet, by M. Stephan.—On the changes of form of Comet IV., 1873, and on its spectrum, by MM. G. Rayet and André. The comet has developed a tail and become brighter; it has no nucleus. Its spectrum at first consisted of three bands, one between D and E, another very close to b, and a third beyond F. After the tail had developed the same bands appeared, bat they were larger and brighter and accompanied by a faint continuous spectrum.—On the form of the Martial seas as compared with the terrestrial oceans, by M. Stan. Meunier. The author considers that the long narrow straits on Mars are an additional proof of its greater age as compared with the earth. Taking the soundings of the Atlantic, he observed that if its level were reduced 4,000 metres (by absorption), it would then present a similar aspect to the Martial seas.
Article PDF
Rights and permissions
About this article
Cite this article
Societies and Academies . Nature 8, 396 (1873). https://doi.org/10.1038/008396a0
Issue Date:
DOI: https://doi.org/10.1038/008396a0