454 Scientific Intelligence. 



indium oxide. After five reerystallizations, the crystals at the 

 least soluble end consisted of pure caesium-gallium sulphate, 

 while the fifth mother-liquor contained gallium and indium oxides 

 in the ratio of 0.6 to 99.4. 



It was found that when 1 g. of pure caesium-gallium alum was 

 mixed with 0.2 g. of zinc oxide dissolved in sulphuric acid and 

 with 0.1 of caesium sulphate a single crystallization gave a 

 product with 98 parts of gallium oxide to 2 of zinc oxide, while a 

 recrystallization of this gave a crop in which zinc could not be 

 detected. The results show that the method is an excellent one 

 for the purpose. — Jour. Amer. Chem. Soc, 43, 126. h. l. w. 



2. A Text-Book of Practical Chemistry ; by G. F. Hood and 

 J. A. Carpenter. Large 8vo, pp. 527. Philadelphia, 1921 (P. 

 Blakiston's Son & Co. Price, $5.00 net). — This is intended to be 

 a reference book for students in connection with experimental 

 laboratory courses. It embraces inorganic preparations, quali- 

 tative analysis, ciuantitative analysis, organic preparations, 

 organic analysis, and physical chemistry, and in each of these 

 main sections there is a careful classification of the matter pre- 

 sented, so that by means of suitable chapter-headings easy refer- 

 ence is assured. 



The book gives a favorable impression as a very useful one for 

 students and teachers in laboratory courses, for it gives a vast 

 amount of accurate information in regard to laboratory experi- 

 ments in various courses of study. Naturally there are differ- 

 ences of opinion in regard to the best methods of procedure in 

 certain operations. For instance, this book states that it is unde- 

 sirable to use the Gooch crucibles for precipitates that have to be 

 ignited, it recommends the use of gentle suction only in employ- 

 ing it, and it advises the introduction of a perforated porcelain 

 filter plate between two layers of asbestos when preparing it for 

 filtration ; whereas, there is no doubt that precipitates may be 

 ignited to redness in the Gooch crucible with the most satisfactory 

 results, that strong suction is desirable to prevent the displace- 

 ment and running through of the asbestos, and that the filter 

 plate is superfluous when strong suction is used. In view of these 

 facts it appears that some, at least, of the British chemists are 

 not taking full advantage of the important American device, the 

 Gooch crucible. 



A good feature of the book is the introduction at the end of 

 each main section of references to the literature of the subject, 

 such as monographs and text-books. h. l. w. 



3. A Dictionary of Chemical Solutilities, Inorganic ; by 

 Arthur Messinger Comey and Dorothy A. Hahn. 8vo, pp. 

 1141. New York, 1921 (The Macmillan Company).— This work 

 is to be welcomed as an exceedingly important addition to chemi- 

 cal books of reference. The first edition, by Dr. Comey alone, 

 appeared 23 years ago, and much material has accumulated since 

 that time, as is shown b}^ the fact that this second edition has 

 more than twice as many pages as the earlier one. 



