Chemistry and Physics. ^55 



Comey's dictionary gives full quantitative data regarding the 

 solubility of inorganic substances, as well as the specific gravities 

 of solutions in many cases, but the unique feature of the work 

 is the fact that it attempts to mention and give the formula of 

 every inorganic compound that has been analyzed. This last fea- 

 ture gives the book a particular importance and usefulness as a 

 book of reference, for it affords an alphabetically arranged list of 

 all the inorganic compounds with references to the original liter- 

 ature. In many cases little is known about the solubility of the 

 compounds, but even the statements given in such cases, showing 

 that they are soluble or insoluble in water, soluble or insoluble in 

 certain acids, decomposed by water, etc., are frequently very use- 

 ful items of information to chemists. 



Comey's dictionary is based in plan upon that of Professor 

 Storer, published in 1864, which some of our older chemists 

 remember as an interesting and important source of reference 

 before the time of the appearance of the more modern work under 

 consideration. 



The great amount of labor involved in the preparation of this 

 dictionary deserves much praise, and it appears that the effort 

 was well worth while in producing a book of such usefulness. 



H. L. w. 



4, Inorganic Chemistry for Schools and Colleges; by James 

 Lewis Howe. 8vo, pp. 443. Easton, Pa., 1920 (The Chemical 

 Publishing Co.). — This text -book now appears in its revised sec- 

 ond edition, thirteen years after its first publication. In the 

 presentation of the subject much attention is paid to the Periodic 

 Law. For instance, separate chapters are devoted to the ele- 

 ments, the hydrides, the halides, etc., in each case with arrange- 

 ments according to the periodic groups. There are luidoubtedly 

 some advantages in this plan, but it brings the descriptions of 

 the metals and their various compounds into several different 

 parts of the book. 



The book presents the fundamental principles and facts of 

 chemistry very clearly, and it is admitted that there is much 

 intentional repetition in order to facilitate thorough teaching. 

 The practical applications of chemistry are rather fully treated 

 and at the end of the book three is an excellent chapter on metal- 

 lurgy. 



A course of simple but instructive laboratory experiments is 

 given by means of concise directions in small print at the bottoms 

 of the appropriate pages. 



The author states that he has made no attempt to incorporate 

 many of the recent advances in chemistry into his elementary 

 book, but, nevertheless, in view of its importance in connection 

 with the atomic theory, it is somewhat unexpected to find no ref- 

 erence to radioactivity when radium is mentioned and to find 

 niton omitted from the periodic table. h. l. w. 



5. Lnminons phenomena in the Lilienfeld tute. — The pecu- 

 liarity of the Lilienfeld X-ray tube is that the electrons emitted 



