Chemistry and Physics. 153 



Vapor Densities and Dissociation," on " Thermo-chemistry " and 

 on " Chemical change " being especially satisfactory. We cor- 

 dially commend the book to those students who desire to 

 acquaint themselves with the modern philosophy of chemistry. 



G. F. B. 



8. Experiments arranged for Students in General Chemistry. 

 — By Edgar F. Smith and Harry F. Keller. 2d. Ed. Enlarg- 

 ed. 8vo, pp. 60. Philadelphia, 1891 (P. Blakston, Son & Co.). 

 " This little work," say the authors in their preface, " is designed 

 for beginners in chemistry." It describes carefully and precisely 

 such experiments as the student can make himself, illustrated 

 with cuts of the apparatus needed. It appears to us admirably 

 adapted to its purpose. G. e. b. 



9. A Text-book of Elementary Chemistry. By George F. 

 Barker, M.D. 2nd Edition, 1891. (John P. Morton & Co., 

 Louisville, Ky.) There are not a few among our teachers of 

 chemistry who believe that in schools of applied science and 

 medicine, where chemistry is taught as a collateral subject, and 

 in required courses in colleges, where but a limited time can be 

 allowed for the acquisition of the principles and facts of this 

 science, the inductive method of instruction is impracticable, and 

 it is partly because of this belief and partly because Dr. Barker's 

 work was admirably arranged, its statements were clear, accu- 

 rate and concise, and the system of nomenclature and notation 

 adopted were judiciously chosen from among the many then com- 

 peting for recognition, that the first edition of his Elementary 

 Chemistry owed the gratifying success which it achieved and has 

 maintained since its publication in 1871. 



This approval has made it seem undesirable in preparing a 

 second edition to alter materially the general plan of the book 

 other than results from the adoption of Mendeleeff's periodic law 

 as the basis of its classification of the elements and for the 

 arrangement of the descriptive part of the book ; the use of the 

 laws of thermo-chemistry in the elucidation of chemical phenomena 

 and in tracing the connection between matter-changes and energy- 

 changes ; and the substitution of the word mass for weight in the 

 terms "atomic weight" and "molecular weight" by which 

 greater precision of statement is effected and the terminology of 

 chemistry is brought into entire accord with that of the rest of 

 the physical domain. Besides this the book has undergone a 

 thorough revision; the newer discoveries in physical chemistry, 

 such as the liquefaction and solidification of the gases and the 

 many other physical constants being recorded from the data of 

 the most recent experiments. Notwithstanding the considerable 

 amount of new matter added, the size of the book has not been 

 materially increased, as in the author's judgment a text-book 

 should contain no more matter than the student may be required 

 to master. c. e. m. 



10. Low Temperatures. — Professor Pictet has established in 

 Berlin a laboratory for work with low temperatures. In order 



