Chemistry and Physics. 399 



6. A Text-Book of Chemical Arithmetic ; by H. L. Wells, 

 12mo, pp. 169, 1905. New York (John Wiley & Sons). — Every 

 instructor in chemistry knows how difficult it is to induce students 

 to use their reasoning powers in solving simple problems. The 

 tendency is always to use a formula or a factor without knowing 

 or caring what these may mean. This text-book is designed to 

 teach chemical arithmetic, but on a basis of reason rather than 

 rules. Part I on approximate numbers deals with calculations 

 from measurements involving errors of observation. The abbre- 

 viated methods of multiplication and division are also given. 

 The rest of the book deals with chemical calculations relating to 

 weights, to gases, and to volumetric analysis. Throughout the 

 book, a large number of very practical problems is given. A 

 student who has once solved these problems intelligently should 

 certainly have no further trouble with chemical calculations. In 

 an appendix, several convenient tables are given, including a table 

 of logarithms. h. w. e. 



7. A Text Book of Physiological Chemistry for Students of 

 Medicine ; by John H. Long, Professor of Chemistry in North- 

 western University Medical School, Chicago. Pp. viii + 424. 

 Illustrated. Philadelphia, 1905 (P. Blakiston's Son). — In this 

 volume are presented in a clear and simple form the necessary 

 facts and principles underlying the science of physiological chem- 

 istry, written for use by students in medical schools, but few 

 references are made to the literature. Besides the general topics 

 usually treated of in a book of this character there is -given an 

 outline of the chemical phases of recent theories of immunity 

 together with explanations of the application of the methods of 

 cryoscopy and electrical conductivity and other physical processes 

 in the field of chemistry related to medicine. The book is well 

 adapted to the purpose for which it was written and should be 

 well received. f. p. underbill. 



8. Formation of Helium from the Radium Emanation. — In 

 answer to many inquiries called forth by an article on this sub- 

 ject, published in the Berichte d. naturf. Ges. Freiburg i Br. 

 xvi, p. 22-2, 1904, F. Himstedt and G. Meyer relate further 

 experiments upon this subject. They have repeated their work 

 with RaBr 2 and also with BaBr 2 by the same method. Using a 

 much greater amount of material, they never found a trace of a 

 helium line. They still possess, however, three tubes which show 

 with the greatest ease the helium spectrum, which could not 

 have come from the air of the room or from any source but the 

 emanation. 



In order to determine whether any occlusion phenomenon sim- 

 ilar to the occlusion of hydrogen by palladium was concerned in 

 the appearance of helium, they made the following experiments : 



Palladium foil filled with hydrogen was placed in a quartz 

 tube connected to a vacuum pump, and in the process of exhaus- 

 tion was heated to a red heat and was flushed out with C0 2 until 

 every trace of the hydrogen spectrum disappeared. After three 



