536 



SCIENCE 



LN. S. Vol. XXV. No. 640 



often studied much, descriptive chemistry, but 

 are not ready for analytical chemistry as or- 

 dinarily taught. Confronted by this difficulty 

 at the University of California, Dr. Morgan 

 has prepared this book, in which " the scheme 

 of qualitative analysis is made to serve as a 

 means of correlating the apparently independ- 

 ent experiments of general chemistry." It is 

 intended primarily for those, " the exigencies 

 of vphose vocational courses render it imprac- 

 ticable " for them " to devote more than one 

 year to general inorganic chemistry and to 

 qualitative analysis as vpell." The author well 

 says in the preface : " Instruction in science 

 should endeavor to equip the student with 

 principles rather than facts, and, what is of 

 still greater import, it should train him in the 

 use of these principles and in the application 

 of them in explaining the phenomena of gen- 

 eral experience." 



The book is divided into four parts: Gen- 

 eral, Descriptive, Analytical, Appendix. Part 

 I. is an outline in sixty pages of the principles 

 of chemistry from the standpoint of physical 

 chemistrj', presupposing a knowledge on the 

 part of the student, of general chemistry as 

 taught in schools. The topics Dissociation, 

 Equilibrium and Mass Action, Hydrolysis, 

 Repression of Ionization, Solute and Solvent, 

 and Oxidation and Eeduction, are treated 

 with satisfactory clearness, and the judicious 

 use of black-letter for important topics and 

 italics for important principles should greatly 

 assist the student. The abandonment of the 

 sign of equations and substitution therefor 

 of the arrow to indicate the general direction 

 of the reaction is a recent innovation, and has 

 much to commend it, and may save the stu- 

 dent from having later to reverse the early 

 acquired notion that a single equation ex- 

 presses quantitatively all that takes place in a 

 reaction. It serves also to emphasize the im- 

 portant conception of equilibrium. 



Part II. comprises about half the book. At 

 first sight, this part, which is a study of the 

 reactions of the elements, would seem to fol- 

 low the plan of many older text-books on 

 qualitative analysis, which weary the student 

 with a mass of test-tube reactions, before he 



comes to any application of their use. In 

 this book we have rather a systematic study of 

 the elements in the order of their occurrence 

 in the periodic table, with special reference to 

 their ions. The method of treatment may be 

 illustrated by the topic Arsenic. This opens 

 with a brief description of the element; then 

 follows its oxidation and solution; the exist- 

 ence of arsenic ions ; its reduction ; the Betten- 

 dorf. Marsh and Reinsch tests; the relation of 

 the arsenious kathion to the hydroxyl, car- 

 bonate, sulfid, sulfate and chlorid anions; 

 arsenic compounds; arsenious acid and arsen- 

 ites; salts of thioarsenious acid; arsenic acid 

 and the reactions of its ion with barium, 

 silver, magnesium and molybdate ions; salts 

 of the thioarsenic acids. One great advantage 

 of this method of study is that the student 

 gains a comprehensive view of the element 

 in all its compounds, and that the sequence 

 of elements according to the periodic table 

 shows him the relation the element bears to its 

 neighbors. Further, those compounds and 

 reactions chosen as illustrations are the ones 

 he meets in analytical chemistry. This divi- 

 sion of the book, as far as I can recall, at- 

 tempts something unique; how it will work 

 practically in other hands than the author's 

 remains to be seen, but it reads as if it would 

 prove successful. 



Part III., on qualitative analysis, opens 

 with solution and preliminary examination of 

 solids. Then follow tables for separations of 

 bases, each with a full discussion conveniently 

 arranged below and on the opposite page. The 

 analysis of acids is similarly arranged with 

 the discussions opposite the tests. Mention 

 should be made of two or three commendable 

 procedures in the course of analysis. In the 

 basic analysis the detection and removal of 

 interfering substances in the filtrate from the 

 hydrogen sulfid precipitate are excellently 

 treated; aluminum, chromium and iron are 

 precipitated as basic acetates, and the chrom- 

 ium oxidized with sodium peroxid; cobalt is 

 removed from the nickel-cobalt solution by po- 

 tassium ferricyanid in the presence of am- 

 monia and a little alum solution, to assist in 

 collecting the cobalt ferricyanid for filtration; 



