Chemistry and Physics. 319 



first place that the gas is very slowly attacked by strongly ozon- 

 ized air, so that the theory of oxidation by atmospheric ozone is 

 very improbable. He has also examined the action of living 

 plants upon air containing small quantities of the gas. The 

 plants were hermetically sealed in glass vessels containing moist- 

 ened sand for the roots and about 1300 cc of air mixed with a 

 known volume of methane, which varied from -^ to ^ of the 

 total volume. After exposures of from six to eleven days the 

 methane remaining in the air was determined by combustion. It 

 was found that from 20 to 82 cc of methane were absorbed by the 

 plants, quantities which usually represented much more than half 

 of the amounts taken. The author believes that he has demonstrated 

 that it is vegetation which prevents the accumulation of methane 

 in the atmosphere. — Co'mptes rendics, cxxxii, 334. h. l. w. 



6. An Introduction to Modern Scientific Chemistry, by Dr. 

 Lassar-Cohn. Translated from the second German Edition by 

 M. M. Pattison Muik. 12 mo., pp. viii, 348. New York, 1901. 

 (D. Yan Nostrand Company.) — This book presents the subject in 

 the form of popular lectures suited for university extension stu- 

 dents and general readers. The difficult task of putting scientific 

 elementary chemistry into an interesting form has been very sat- 

 isfactorily accomplished, and the work will be useful, not only to 

 beginners in chemistry, but also to teachers who are studying the 

 methods of presenting the subject. A good feature is the intro- 

 duction of a simple treatment of organic chemistry which is 

 more comprehensive than is usual in works on elementary chemis- 

 try, and even such subjects as the isomeric benzene derivatives, 

 the asymmetric carbon atom, and the alkaloids are briefly consid- 

 ered. The short discussion of agricultural chemistry is particu- 

 larly well done, and there are many other excellent features. 

 Where so much has been crowded into a small space, it is hardly 

 fair to notice omissions, but it seems that the modern theories of 

 solution should have received mention. Certain equations, how- 

 ever, that are given, for example, 



K - OH + NO a - OH = N0 2 - OK + H 2 0, 



make it seem probable that the author is not in sympathy with 

 the ionic hypothesis. Very few errors in regard to facts have 

 been noticed, but a mistake is made where it is stated that in gun 

 cotton, C 6 H 7 N 3 11 , there is plenty of oxygen to burn the carbon 

 to carbon dioxide, and the hydrogen to water. The book is sup- 

 plied with 58 illustrations by the author. Some of these show a 

 little weakness in perspective, but they answer their purpose 

 admirably and bring out clearly the important points. . 



h. l. w. 

 1. Ausgewaldte Methoden der Analytischen Chemie, von Prof. 

 Dr. A. Classen. Erster Band. 8 vo, pp. xx, 940, Braunsch- 

 weig, 1901, (Vieweg und Sohn). This work is intended as a guide 

 for the practical analytical chemist. The present volume is upon 

 the metals. It takes up their qualitative reactions as well as their 



