Abstract
PARIS. Academy of Sciences, September 15.—M. Bouquet de la Grye in the chair.—The cultivation of the yellow lupin (Lupinus luteus), by MM. P. P. Dehérain and E. Demoussy. The poor yield of this plant on calcareous soil appears to be due to the effect of the lime in preventing the assimilation of phosphoric acid, since if considerable quantities of phosphate are added, the plant will grow in soils containing a fair proportion of lime. The tubercles containing bacteria capable of fixing atmospheric nitrogen do not, however, appear under these conditions, not even when the yellow, lupins are inoculated from the tubercles of white lupins. The growth is best in non-calcareous soils.—On the principal focal surface of the objective of, the photographic equatorial of the Observatory of Toulouse, by MM. B. Baillaud and Montangerand.—On the rocks thrown out by the actual eruption of Mont Pelée, by M. A. Lacroix. From the external appearances, three classes of rocks can be distinguished, compact vitreous blocks of a greyish-black colour, rocks of a clearer colour than these, and angular blocks of white pumice, sometimes as large as a cubic metre. All these have proved to be of the same petrographical type; they consist of hypersthene andesites rich in phenocrystals, the latter consisting of plagioclases of the andesine and bytownite series. The principal coloured element is hypersthene, accompanied by titanomagnetite and small quantities of augite, hornblende and olivine. The products of the eruption have the same general character as the rock mass of Mont Pelée formed in the course of previous eruptions.—On the differences of contact potential, by M. Pierre Boley. A study of the electromotive forces of the cell constructed of the saturated amalgams of two metals, with two electrolytes.—On the electrical resistance of slightly conducting bodies at very low temperatures, by M. Edmond van Aubel. The electrical resistance of iron pyrites was. measured for a temperature range of from 60° C. to -181° C. The resistance increases considerably as the temperature is lowered, but there is still an appreciable conductivity at the temperature of liquid air. The curve showing the variation of the electrical resistance of iron pyrites with temperature shows that AR/Δt increases as the temperature approaches the absolute zero. Experiments on other metallic sulphides are being carried out.—On a note of M. Th. Tommasina, on the mode of formation of kathode and Röntgen rays, by M. Jules Semenov.—On the formation of liquid drops and the laws of Tate, by MM. Ph. A. Guye and F. Louis Perrot. With other conditions fixed, the weight of a drop falling from the end of a tube is a function of the time of formation of the drop. It follows that any attempt to verify Tate's law, in which the time of formation is not taken into account, is wanting in precision. It is essential that the conditions of experiment should be so arranged that the weight of the drop should be independent of the time of formation. In view of these facts, the authors consider that the experiments of MM. Leduc and Sacerdote do not furnish even an approximate proof of the law in question.—On the production of india-rubber in the forests of the French Congo, by M. Aug. Chevalier. Observations on Landolphia Klainii, the chief india-rubber-producing tree in the French Congo.
Article PDF
Rights and permissions
About this article
Cite this article
Societies and Academies . Nature 66, 544 (1902). https://doi.org/10.1038/066544a0
Issue Date:
DOI: https://doi.org/10.1038/066544a0