Chemistry and Physics. 349 



The authors have examined a considerable number of crops of 

 the mixed crystals, and by the determinations of water and of 

 sodium sulphate in the carefully prepared and dried substances 

 have shown beyond doubt that the sodium sulphate is in the form 

 of the tetrahydrate. They have found, further, that the amount 

 of sodium sulphate in the crystals is somewhat less than one-half 

 of the quantity corresponding to the same weight of sodium 

 chromate in the mother liquor. — Jour. Amer. Chem. Soc, 43, 

 1543. H. L. w. 



3. A Text-hook of Organic Chemistry ; by Joseph Scudder 

 Chamberlain. 8vo, pp. 959. Philadelphia, 1921 (P. Blakis- 

 ton's Son & Co. Price, $4.00 net). — In the preparation of this 

 book the author has endeavored to make it sufficiently elementary 

 for the purpose of a first course in the subject and at the same 

 time to make it comprehensive by taking up practically all the 

 important groups of compounds, and presenting an unusually 

 large number of them. 



A striking feature of the book is the clear and excellent dis- 

 cussion of the structures of organic compounds in connection 

 with their syntheses and other reactions. The very numerous 

 developed formulas and equations of reactions are very satis- 

 factorily given. 



The book appears to be a very good one for a first course and 

 also for more advanced students. On account of its large scope 

 it may appear somewhat formidable to the beginner, but the mag- 

 nitude and complexity of the subject seem to warrant the avoid- 

 ance of texts that are too much abbreviated and simplified. 



H. L. w. 



4. Quantitative Chemical Analysis; by Henry P. Talbot. 

 8vo, pp. 203. New York, 1921 (The Macmillan Company).— 

 This is the sixth edition, completely rewritten, of a book which 

 presents a well-selected course of laboratory work for students. 

 The directions given are very clear and satisfactory, while the 

 numerous explanatory notes are excellent. 



Contrary to the usual custom the volumetric course in this 

 edition precedes the gravimetric one, because the author has 

 found by experience that this order of work appears to furnish the 

 better approach to the subject. More than 100 well chosen and 

 instructive problems with answers, make a valuable feature of 

 the book. 



In connection with weighing the author says, "The correct 

 weight is that which causes the pointer to swing an equal number 

 of divisions to the right and left of the zero-point, when the 

 pointer traverses not less than five divisions on either side. ' ^ 

 The long swing thus recommended deserves strong adverse crit- 

 icism, for although fairly good weighing can perhaps be done in 

 this way in spite of the appreciable retardation of each single 

 swing of such length, it is undoubtedly much easier and quicker 



