698 



SCIENCE. 



[N. S. Vol. II. No. 47. 



the best medium through which to gain a know- 

 ledge of general chemistry either of the metals 

 or the non-metals ; indeed it is probable that 

 the importance of qualitative analysis has been 

 much over-estimated. It is of course necessary 

 for those who intend to make a thorough study 

 of the science, but the majority of college stu- 

 dents do not pursue chemistry more than a sin- 

 gle year, and it should not be difficult to devise 

 a year's course in chemistry in which the stu- 

 dent would gain far more knowledge of chem- 

 istry and more intellectual development than 

 in the ordinary course, where such a large por- 

 tion of the time is spent on qualitative analysis. 

 There are dozens of laboratory manuals before 

 us, in many, not to say most, of which the 

 author's effort has apparently been to boil the 

 matter down to the least possible space ; the 

 result has been the production of a series of 

 more or less extended tables which the student 

 follows blindly in searching for the contents of 

 his unknown solutions, knowing nothing of the 

 reasons for any step and gaining no knowledge 

 of chemistry. Indeed, one may become a good 

 analyst and know little of chemistry. 



There are however teachers who use qualita- 

 tive analysis as merely a medium of instruction 

 in chemistry; who subordinate the acquisition 

 of analytical skill to the acquisition of a knowl- 

 edge of general chemistry and chemical theory. 

 Such an one is the author of this book, and the 

 present edition of his manual is the fruit of over 

 three decades of laboratory teaching. The 

 result is not a manual for self-instruction, but 

 rather a guide to be used under the immediate 

 supervision and instruction of a competent 

 teacher. 



The first half of the book is devoted to the 

 reactions of the more common bases and acids, 

 the students working with known solutions of 

 a single salt and writing out each reaction on 

 the blank images with which this part of the 

 book is interleaved. In this manner the stu- 

 dent becomes familiar with these reactions, 

 which represent all the ordinary ones used in 

 qualitative and quantitative analysis. As he 

 progresses in this work he is supposed to be fur- 

 nished with solutions of unknown single salts 

 for determination. This part is also intended 

 to be supplemented by a course of lectures on 



the metals and their compounds. The second 

 part of the book is devoted to the systematic 

 examination of solids. The method used here 

 is that which was first introduced by the author 

 and is now with greater or lesser modifications 

 generally in use. It is safe to say, however, 

 that little improvement has been made upon 

 the original. 



This is followed by qualitative separations. 

 Here, while alternate methods are now and then 

 given, the methods are generally confined to 

 that one in each case which has proved itself 

 best in the author's experience. There is a 

 decided advantage in thus limiting the possible 

 modes of procedure, as freedom of choice is 

 confusing to the novice. Indispensable as Fre- 

 senius is to the advanced student, it is almost 

 useless to the inexperienced. 



A supplement gives fully the reactions of 

 nearly all the rare elements, while a chapter in 

 the appendix on the preparation of reagents 

 will be useful to teachers. The earlier editions 

 of the book have proved its success in the hands 

 of no inconsiderable number of teachers beside 

 the author, and this rexdsed edition, which is a 

 very considerable improvement on those which 

 have preceeded it, will be found even more 

 valuable. If chemistry is to continue to be 

 taught as largely through qualitative analysis 

 as it has been in the past, this manual may 

 safely be recommended as the best of its class. 

 It is the writer's hope, however, that the day is 

 not far distant when the improvement will be 

 not along the old lines, but in the methods of 

 chemical teaching themselves. The general 

 style and make-up of the the book is good, but it 

 is unfortunately marred by poor proof-reading. 

 Jas. Lewis Howe. 



Washington and Lee University, 



Lexington, Va., October 19, 1895. 



La sensibilite de Vceil aux couleura spectrales. 

 M. H. Parinaud. Revue Seientifique, S6r. 4, 

 T. 4, 134—141. August 3, 1895. 



In the Revue Seientifique for June 8, Parinaud 

 described an interesting series of experiments 

 on the relative sensibility of the adapted and 

 unadapted eye to spectral colors.* In the issue 

 of the same journal for August 3 he gives his 



*See review in Science, XL, 418, Sept. 27, 1895. 



