Chemistry and Physics. 157 



would require about 13 years to eliminate the two atoms of oxy- 

 gen in excess. — Rev. Trav. Chim. y xvii, 129-176, 1898; J. Chem. 

 Soa, lxxiv, ii, 516, Nov. 1898. g. f. b. 



6. On Neodymium. — According to Botjdotjard, neodymium can 

 be isolated by allowing a solution of the pure sulphates of the 

 yttrium metals to remain in contact with potassium sulphate in 

 excess for at least 24 hours, then decomposing the insoluble 

 double sulphate thus produced, with sodium hydrate, dissolving 

 the oxide in nitric acid and precipitating with oxalic acid. The 

 substance thus prepared afforded the atomic mass 143, agreeing 

 well with 142*7 ordinarily assigned to this metal. The oxide is 

 greenish, while the oxalate and anhydrous sulphate are slightly 

 rose-colored. The crystallized sulphate, also rose-colored, while 

 less soluble than the anhydrous sulphate, is more soluble in cold 

 water than in hot. A solution of the sulphate gives an absorption 

 spectrum having a shadow from 591*5 to 584, an intense band from 

 584 to 572, another from 523 to 519, a feeble band from 512 to 

 508, and faint bands at 480 and 470, due probably to traces of 

 praseodymium. The double sulphate of potassium and neody- 

 mium is more soluble than the corresponding compound of pra- 

 seodymium. — C. R., cxxvi, 90 0-901, March, 1898. g. f. b. 



7. Lepons de Chimie Physique professees d V University de 

 Berlin • par J. H. Van't Hoff, Professeur ordinaire a l'Univer- 

 site, etc. Ouvrage traduit de l'allemande par M. Corvisy. Pre- 

 miere Partie, La Dynamique Chimique. 8vo, pp. 263. Paris, 

 1898 (A. Hermann). — The lectures delivered by Professor Van't 

 Hoff during 1897 were upon "Selected subjects in Physical Chem- 

 istry " and were divided into three parts, the first comprising 

 Chemical Dynamics, the second Chemical Statics, and the third 

 Relations between the Properties of Substances and their Compo- 

 sition. The present volume contains the first part only ; and like 

 all the productions of this eminent authority, is full of the most 

 valuable material admirably classified and clearly treated. The 

 subject is divided into two principal sections, the first on Chemi- 

 cal Equilibrium and the second on Speed of Reaction ; each of 

 these being subdivided into two parts, the former section into 

 Chemical Equilibrium in its Physical and especially its Thermo- 

 dynamic relations and Chemical Equilibrium in its Mechanical 

 and Molecular relations ; and the latter section into Theoretical 

 laws of reaction speeds and Experimental results of Reaction 

 speeds. The translator seems to have done his work with care 

 and thus to have made available this excellent presentation of the 

 subject to a much larger class of students. g. f. b. 



8. Outlines of Industrial Chemistry ; a Text-book for Students. 

 By Frank Hall Thorp, Ph.D. 8vo, pp. xx, 541. New York, 

 1898 (The Macmillan Company). — Dr. Thorp has given us in 

 this book a compendium of commercial chemical processes which 

 cannot fail to be of use to the technical student. The first part is 

 devoted to Inorganic industries such as relate to fuels, waters, 

 the soda industry, the chlorine industry, fertilizers, cements, glass 



