Chemistry and Physics. 317 



quite completely after being preserved in closed vessels for a few 

 months. They believe, therefore, that the radio-activity of 

 thorium compounds is not inherent but induced by the uranium 

 contained in the minerals from which they are extracted. This 

 view is confirmed by the fact that thorium from monazite sand 

 containing no uranium is entirely inactive, while preparations 

 from broggerite, cleveite, samarskite, thorite and orangite are 

 most active in the cases where the larger quantities of uranium 

 are present. — Berichte, xxxv, 531. h. l. w. 



5. Lithium Antimonide. — It has been found by Lebeau that 

 antimony and lithium combine with violence when they are 

 heated together, but that the heat thus produced prevents the 

 preparation of a definite compound. However, upon electrolyz- 

 ing a mixture of the chlorides of potassium and lithium with a 

 cathode of antimony, a definite crystalline compound correspond- 

 ing to the formula Li 3 Sb is produced. The same compound can 

 be prepared by the action of lithium dissolved in liquefied ammo- 

 nia upon metallic antimony. It is somewhat soluble in the 

 ammonia, giving the compound Li 3 SbNH 3 upon evaporation. — 

 Comptes Pendus, cxxxiv, 231, 284. h. l. w. 



6. A New Synthesis of Formic Acid. — Moissan has found 

 that the hydrides of potassium and sodium take fire at ordinary 

 temperatures in an atmosphere of carbon dioxide. If the tem- 

 perature produced by the reaction is not allowed to rise too high 

 so as to destroy the product, it is found that a formate is pro- 

 duced. In the case of potassium hydride the reaction is as 

 follows : 



C0 2 + KH = HCOOK. 



It was found also that carbon monoxide is slowly attacked by 

 potassium hydride with the formation of formate and carbon 

 according to the equation, 



2CO + KH = HCOOK + C. 

 — Comptes Hendus, cxxxiv, 263. h. l. w. 



7. Elements of Physical Chemistry y by Harry C. Jones. l 

 8vo, pp. 549. New York, 1902 (The Macmillan Co.).— This 

 volume is designed especially as a text-book for advanced 

 students of chemistry and physics. The author makes the point 

 in the introduction that we are too much inclined at present to 

 treat physical chemistry as a subject which has originated in the 

 last fifteen years. So he has devoted much space to the work of 

 the earlier investigators — work which was really the foundation 

 of much that has developed in the last few years. At the same 

 time, the modern theories and their applications are taken up 

 very thoroughly and very well. 



From the standpoint of the teacher, the treatment seems occa- 

 sionally a little too mathematical, for the average student in 

 chemistry is certainly not well grounded in higher mathematics. 

 For instance, the relation between the specific heats of gases at 

 constant pressure and at constant volume can be explained 

 equally well without the use of calculus. h. w. f. 



