4:14 Scientific Intelligence. 



with breaks at each step of the reaction with the trivalent salt. 

 The addition of NaOH to Zn(N0 3 ) 9 gives breaks corresponding 

 to the formation of ZnN0 3 OH, of Zn(OH) 2 and of Zn(ONa) 2 

 and similar results are obtained with NaOH and lead, mag- 

 nesium and copper salts. The salts of Cu, Co and Ni give 

 evidence of the formation of successions of complexes as NH 3 

 is added. It is to be expeected that this method of investigation 

 will be of great value in furnishing a very simple method for 

 the investigation of many chemical reactions. — J. chim. pharm., 

 19,321 (1922). h. l. w. 



3. Theories of Organic Chemistry ; by Ferdinand Henrich. 

 Translated and Enlarged by Treat B. Johnson and Dorothy A. 

 Hahn. 8vo, pp. 603. New York, 1922 (John Wiley & Sons, 

 Inc.). 



The wonderful achievements in connection with the theories 

 applied to the carbon compounds are extremely well presented 

 in this book, and it furnishes a most excellent source of informa- 

 tion for advanced students and teachers of chemistry. The 

 translators deserve much praise for making this important 

 German work available for the use of English-reading chemists, 

 as well as for the introduction of several new chapters and 

 other additions which deal particularly with the work of Ameri- 

 can investigators, especially with that of the late J. U. Nef 

 and of Arthur Michael. The German author has furnished a 

 preface to the American Edition in which he approves of these 

 additions and modifications. 



The subject is presented historically, with naturally less 

 attention to the older, superseded views than to those now pre- 

 vailing or under active consideration. The discussions of the 

 modern theories are very full and clear, the translation of the 

 German text into English appears to be most excellent, and 

 the difficult typography involving many, frequently complex, 

 structural formulas has been very well done. h. l. w. 



4. The Chemistry of Combustion; by J. Newton Friend. 

 12mo, pp. 110. New York, 1922 (D. Van Nostr and Company. 

 Price $1.25 net) . — This monograph is the outcome of a series of 

 lectures recently delivered by the author in the Birmingham 

 Municipal Technical School. It gives a clear and satisfactory 

 presentation of the subject in its modern aspects, and since 

 it appears that there has been no small text-book of this kind 

 to which students may be referred, it may be regarded as 

 filling an obvious gap in our literature. 



The first chapter is devoted to definitions, then the phlogiston 

 theory is briefly discussed, while the other sections are devoted 

 to the combustion of solid carbon, flame, the combustion of 

 gaseous hydrocarbons and other gases, ignition temperatures, 

 the inflammation of gaseous mixtures and the propagation of 



