512 SCIENTIFIC KECORD FOR ISS^ 



mean of six experiments C = 11.9757. Dumas and Stas in 1840 ob- 

 tained 11.9708. {Comptes Revdvs, civ, p. 1180.) 



Uranium. — Zimmermann has prepared metallic uranium by Peligot's 

 method and studied its properties. Its specific gravity is 18.685, and 

 its specific heat between 99° and 0° is .02765; the latter number multi- 

 plied by 240 gives a product of 6.64, which agrees with the mean atomic 

 heat indicated by Dulong and Petit's law. This settles the controversy 

 concerning the correct value in favor of 240 and in accordance with 

 Mendelejeff's classification. {Berichted. chem. Ges., xv, p. 847.) 



Glucinum. — Dr. James Blake thinks that the evidence derived from the 

 physiological action of the salts of glucinum may be of use in determin- 

 ing its true position among the elements. He finds that the effects pro- 

 duced by the introduction into the blood of salts of Be are the same as 

 those caused by the salts of alumina and of ferric oxide. He regards 

 glucinum as a member of the aluminium group of metals. {Chem. News, 

 XLV, p. 111.) 



Aluminium. — The atomic weight of this element has been subjected 

 to a painstaking revision by Prof. J. W. Mallet. The general mean of 

 30 experiments gives Al = 27.032, with a probable error of dL 0.0045. 

 [Oxygen = 15.901.] {Chem. Netrs, XLV, pp. 256 e< seg.) 



Rubidium. — Charles T. Heycock has redetermined the atomic weight 

 of rubidium with the view of testing its relation to Prout's hypothesis. 

 The figures obtained by titration of the chlorine in pure chloride of 

 rubidium are 85.344; and those by titration of the bromide are 85.387, 

 results which lead the author to the conclusion that at present rubidium 

 cannot be regarded as conforming to Prout's hypothesis. {Report of 

 British Assoc, in Nature, xxvi, p. 467.) 



Didymium. — Brauner has determined the atomic weight of didymium 

 as M6.18, and that of lanthanum as 138.88. {J. Chem. Soc, xli, p. 68.) 



Yttrium has been prepared by Cleve free from terbium and its atomic 

 weight redetermined. He assigns the value 88.9 to Y'" when O^ 15.9033. 

 {Comptes Rendus, December 11, 1882.) 



Thorium. — L. F. Mlson has redetermined the atomic weight of tho- 

 rium by ignition of the carefully purified sulphate: Th (804)2.9 fl20, 

 and obtains as a mean of ten experiments 232.40. {Berichte d. chem. 

 Ges., XV, p. 2519.) 



A recalculation of the atomic weights, by Prof. E. W. Clarke. — Brief 

 mention must be made in this connection of the systematic recalculation 

 of the atomic weights carried out by Professor Clarke and published by 

 the Smithsonian Institution as Part Y, of the Constants of Nature. 

 Chemists are under great obligations for this invaluable treatise. 



Composition of the Atmosphere. 



Several chemists have carried on independently more or less elaborate 

 researches on this subject. Eeiset has made numerous determinations 

 of the amount of carbonic anhydride in the atmosphere, and finds the 



