Societies and Academies

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    Academy of Sciences, August 29.—M. Duchartre in the chair.—Observations of the new planet M. Wolf, made at the observatory of Paris (west equatorial), by M. G. Bigourdan. From observations of comparison stars, the R. A. of the planet in question on August 27, at I2h. 20m. 33s. p.m. Paris mean time, was 22h. 41m. 24˙95s., its apparent declination– 10° 25′ 5l″˙8, and its magnitude 12˙5.–Measures of the diameter of Mars, by M. Camille Flammarion. To settle the divergence between the values of the diameters of Mars as predicted by the Nautical Almanac, the Connaissance des Temps, and Marth's “Ephémérides,” measurements were taken with the 24cm. equatorial of the Juvisy observatory, resulting in values ranging from 24″˙50 to 24″˙91. These confirm Marth's calculations, while the other two ephemerides are about 5″ in excess, based as they are upon Leverrier's tables instead of Hartwig's.—On the solar phenomena observed at the Royal Observatory of the Roman College during the second quarter of 1892, by M. P. Tacchini.—On the bacterian origin of the bilious fever of hot countries, by M. Domingos Freire. A microscopic comparison of the germs of the yellow fever with those of the somewhat similar bilious fever of tropical countries shows that the former is due to a micrococcus, which is round, highly refractive, and easily coloured by fuchsine, methyl blue, &c., whereas the bilious fever is originated by a bacillus which the writer has succeeded in cultivating. It is about nine microns long and three broad. It is motionless, and accompanied by numerous moving spores. Each bacillus undergoes rapid segmentation into two parts, which give rise to terminal spores. It has been found possible to produce the disease in a pig by inoculation.—On the comparative assimilation of plants of the same species, developed in the sun and in the shade respectively, by M. L. Geneau de Lamarlière. A series of quantitative results, showing that under similar external conditions the decomposition of carbonic acid varies in intensity, for leaves of the same species, according to the conditions of development of these leaves; and that the leaves of a species developed in the sun, all other conditions being equal, decompose the carbonic acid of the air more energetically than those developed in the shade.—On the present eruption of Etna, by M. Wallerant. The eruption of 1892, without having the importance of that of 1865, is, from several points of view, superior to that of 1886; the flows of lava are more extended and the craters more numerous. On July 8 the volcano gave its usual warnings. Thick columns of black smoke emerged from the principal crater, and earthshocks were felt as far as Catania. On the following day the eruption began in earnest. Two openings appeared a short distance apart, one of which only gave off steam, while the other gave rise to a flow of lava which passed westwards of Monte Nero, and which has been called the western stream. It was not till after the flow had ceased that four volcanic cones arose successively from north to south at a distance of about 60 m. to the east of this cleft. Another flow of lava passed to the east of Monte Nero, and was called the eastern stream. For about a month the eruption followed its normal course; the lava continued to flow and the cones increased in height. But on August 9 important modifications took place. The ejections diminished and the explosions ceased. It was thought that the disturbance was dying out, but on the 11th such an eruption of steam took place that Etna disappeared entirely in an absolutely opaque cloud. At the same time it was found that the lava, leaving the first tracks, had taken a new path across the vineyards. In the morning of the 12th the opening of a new crater in the line of the preceding ones was found in the act of building up a cone. The previous evening the observers had passed over the same spot and had found small vents giving off vapours, but nothing to indicate the formation of a crater in so short a time. The formation of this crater was accompanied by a complete cessation of the ejections from the second volcanic cone, which had been very violent. The eruption thus seemed to have entered a new stage of development.

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    Societies and Academies. Nature 46, 460 (1892) doi:10.1038/046460a0

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