Societies and Academies

    Abstract

    PARIS Academy of Sciences, September 3.—M. Blanchard, president, in the chair.—The silting was chiefly occupied with the reading of the report on the French mission to the Pacific to observe the total eclipse of the sun on May 6, 1883. The report was prepared and read by M. J. Janssen, head of the mission, to which, besides M. Trouvelot, of the Meudon Observatory, and M. Pasteur, photographer, were also attached MM. Tacchini, director of the Roman Observatory, and Palisa, of the Vienna Observatory. The station selected was Caroline Island, in 10° S. and 152° 20′ W., about 200 leagues north of Tahiti, a point lying very nearly within the zone of total obscuration. In the report are summed up the results of all the observations, which aimed especially at the solution of certain questions touching the contitution of the sun and the existence of the so-called intra-Mercurial planets. As regards contact the commencement of total obscuration was determined at 23h. 31m. 51.8s. mean time at Caroline Island; end of same 23h. 37m. 15.8s., leaving a difference of 5m. 24.1s. as the actual duration of totality according to M. Trouvelot. M. Tacchini gave 5m. 23s., or a difference of slightly over one second, which was considered as so far satisfactory. M. Tacchini also made some remarkable observations, especially touching a certain analogy between the constitution of the spectrum of certain parts of the corona and that of comets. In his attempt to ascertain whether the light of the corona contains any large proportion of solar light, M. Janssen succeeded beyond his expectations. The complete Frauenhofer spectrum seen by him shows that, apart from what may be due to diffraction, there exists in the corona, and especially in certain parts of it, an enormous mass of reflected light. And as the coronal atmosphere is known to be extremely attenuated, such an abundance of reflected solar light can be explained only by the presence in these regions of cosmic matter in the form of solid corpuscules. The photographs of the corona yielded several interesting phenomena, which are reserved for future study. For the present it will suffice to remark that these photographs show a more extended corona than that obtained from telescopic observation. The phenomenon also appeared limited and fixed during the period of total obscuration. A photometric measurement of the luminous intensity of the corona, which M. Janssen had prepared by means of photography, showed that in Caroline the luminosity of the corona was greater than that of the full moon. This is the first time that a precise calculation has been made of this phenomenon. On May 13 the mission re-embarked on board the Eclaireur, and on the home voyage visited Hawaii during the volcanic disturbances in the crater of Kilauea. M. Janssen took this opportunity of making a spectrum analysis of the flames emitted by the molten lavas, and was able to determine the presence of sodium, hydrogen, and carburetted combinations.—On the antiseptic frigidity of sores, by M. Gosselin.—Note by M. J. Delauney on the indications some years ago formulated by him on the probable epochs of great earthquakes. In a note inserted in the Comptes Rendus for November 17, 1879, the author considered it probable that the influence of Jupiter and Saturn on seismic disturbances is due to the passage of these planets through meteoric bodies situated in the mean longitudes of 135° and 265°. In the approximate table of future earthquakes accompanying the note, the tyear 1883 was not mentioned. But in another note inserted in La Nature for October 23, 1880, a fresh calculation of probable epochs of seismic agitation, brought down to the year 1920, mention is made of the date 1883-85, when disturbances might be expected owing to the transit of Jupiter through the August meteors.—Observations of the new planet (234) made at the Paris Observatory (equatorial of the west tower), by M. G. Bigourdan.—On the affinities of the eocene floras of England and the west of France, by M. L. Crié.—Fresh remarks on the Phylloglossum Drummondii (Kunze), by M. C. Eg. Bertrand.—On a process for extracting alcohol by means of lemon juice, by M. Levat.—On the fermentation of bread-stuffs, by M. G. Chicandard.

    Rights and permissions

    Reprints and Permissions

    About this article

    Cite this article

    Societies and Academies . Nature 28, 480 (1883). https://doi.org/10.1038/028480a0

    Download citation

    Comments

    By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.