208 Scientific Intelligence. 



Upon reading this article one would suppose that these com- 

 pounds were new ones, and of a new type. The authors refer 

 to some work by Bohm in 1905 upon acid fluorides of cobalt, 

 nickel and copper, and say, "The formulas assigned by Bohm 

 to these fluorides are of a strongly acid type. ' ' Nothing further 

 is said about Bohm's formulas, but upon consulting Bolim's 

 article it appears that he described, besides others, the salts 



CuF..5HF.5H.O, 



NiF;.5HF.6HoO, 



and CoF:.5HF.6II;0, 



two of which are identical with those of Edmister and Cooper, 

 while the other one varies by only a single molecule of water. 

 Bohm described also the crystalline form of all of these salts. 

 There is no doubt that Edmister and Cooper should have 

 mentioned Bohm's results. — Jour. Amer. Chem. Soc, 42, 2419. 



H. L. w. 



3. Notes on Chemical Research, bv W. P. Dreaper. 12mo, 

 pp. 195. Philadelphia, 1920 (P. Blakiston's Son & Co.).— This 

 book from England now appears in a considerably enlarged 

 second edition. It gives a general discussion of chemical 

 investigations, and is intended particularly for the use of young 

 chemists who are engaged or about to be engaged in industrial 

 work. The book is an interesting one and it gives much useful 

 information and advice. Many will not agree with the 

 opinion of the author tliat a post-graduate course of research 

 work in college is of doubtful advantage to the industrial 

 research chemist, but very probably this opinion is the correct 

 one in connection with most of the chemical manufactures in 

 England. The view is expressed that it is seldom that a man 

 can combine the experience and qualifications of a first-class 

 chemist and of an engineer; hence the combination of the two 

 professions in the "so-called chemical engineer" is not approved 

 of. H. L. w. 



4. Elementary Chemistry for Coal-mining Students; by L. 

 T. O'Shea. 12mo, pp. 319. London, 1920 (Longmans, Green 

 and Co. Price, New York, $3). — This book has been prepared 

 for the use of a special class of students, for whom the ordinary 

 text book of chemistry is not well adapted, since it contains 

 much that is unnecessary for them to study, and since much 

 that it is desirable for them to know is not found in it. It 

 appears that the book is a very satisfactory one for its purpose. 

 It presents clearly the fundamental principles of the science, 

 it discusses particularly the elements occurring in coal, while 

 special attention is paid to the explosive, suffocating and poison- 

 ous gases that may occur in coal mines. The chemistry and 

 technology of coal and coke and the by-products are well 

 presented, while the discussions of explosives and explosions of 



