390 Scientific Intelligence. 



this property. The author believes that the constancy of the 

 activity must depend upon external conditions which it will be 

 very important to determine, and he suggests the possibility that 

 under certain conditions the activity of other substances, such as 

 uranium, thorium, radium, and actinium, will diminish and dis- 

 appear in the same manner as that of polonium. — Comptes Ren- 

 dus, cxxxix, 283. h. l. w. 



3. Condensation of Helium and Hydrogen by Charcoal. — 

 As a continuation of his studies on the condensation of gases by 

 charcoal,* Sir James Dewae has obtained some interesting 

 results with hydrogen and helium. Two discharge-tubes, pro- 

 vided with small condensers containing 1 or 2 g. of wood char- 

 coal were filled, one with hydrogen and the other with helium at 

 atmospheric pressure. The little charcoal condensers were now 

 plunged into liquid hydrogen, with the result that the vacuum 

 became so high that no electric discharge would pass in the tube 

 filled with hydrogen, while in the tube containing helium the 

 vacuum was high enough to obtain the phenomenon of phospho- 

 rescence under the action of the discharge. Two similar tubes 

 containing helium from different sources were then subjected to 

 the action of liquid hydrogen boiling under exhaustion, which 

 produced a temperature of 15° absolute. In each case the 

 vacuum resulting from the occlusion of the helium was so high 

 that a coil giving a spark of 4 cm in air had to be used to obtain 

 an intermittent phosphorescent discharge. From comparative 

 experiments with hydrogen and helium it is concluded that the 

 boiling point of helium is about 6° absolute. — Comptes JRendus, 

 cxxxix, 421. h. l. w. 



4. Hie Biechstoffe ; von Dr. Georg Cohen. 8vo, pp. 219. 

 Braunschweig, 1904 (Vieweg und Sohn). — This book deals with 

 those organic products — synthetical and natural — that are dis- 

 tinguished by some characteristic odor, particularly those which 

 have found commercial application in the manufacture of per- 

 fumes. A great number of synthetical products are described, 

 including alcohols, ethers, esters, aldehydes, ketones, and bases ; 

 and the reactions by which each class can be identified are dis- 

 cussed. A part of the book is devoted to tables relating to the 

 numerous ethereal oils ; their physical constants and chemical 

 compositions are given, together with the names of the plants 

 from which the oils are obtained. A short discussion of the rela- 

 tion between odor and chemical constitution is also given. The 

 references to patent literature are very full. While the book 

 will be of little interest to the theoretical chemist, it will be of 

 use to the technical chemist who is interested in the manufacture 

 of perfumes. t. b. j. 



5. Volumetric Analysis ; by Francis Sutton. Ninth edi- 

 tion, revised and enlarged. 8vo, pp. 617. Philadelphia, 1904 

 (P. Blakiston's Son & Co.). — This standard work on volumetric 

 analysis is so universally known among English-speaking chemists 



* See this volume, pp. 290 and 295. 



