﻿238 Notices respecting New Books, 



seems to have been made as thoroughly as such a work deserved; 

 and no pains have been spared in making it perfect down to the most 

 minute particular. It had, we believe, been long out of print; and 

 we congratulate students of Mechanical Science on being able to 

 procure what will long be the standard work on this subject. 



A Laboratory Text-book of Practical Chemistry ; or, Introduction to 

 Qualitative Analysis. A Guide to the Course of Practical Instruc- 

 tion given in the Laboratories of the Royal College of Chemistry. 

 With ninety engravings. By Wm. G. Valentin, F.C.S. London : 

 Churchill, 1871. Pp. x and 380. 



"When the preliminary stages in the growth of an idea or an opi- 

 nion have been passed, it invariably happens that a literary embodi- 

 ment is found necessary. The great and increasing estimation in 

 which physical science is now held as at once a means and object of 

 education, furnishes many an illustration of this ; and, in its turn, 

 physical science has to embody successive opinions and ideas as 

 they arise. Thus a perfect scientific literature would be a diffused 

 history. 



Mr. Valentin's text-book is very remarkable (indeed, novel) in one 

 respect. It puts prominently forward, as an element in the teach- 

 ing of analysis, the most advanced form of the atomic method of 

 symbolization ; and it does so expressly on the ground that the study 

 of chemical analysis is thereby simplified in a marked degree. It 

 has hitherto been the custom for writers of analytical works to keep 

 formal chemistry very much in the background, and to regard even 

 equations rather as impedimenta than active aids. But some change 

 has long been expected, and was clearly inevitable. When the re- 

 sults of chemical research are almost uniformly expressed, not only 

 in atomic language, but in atomic symbols, and almost every me- 

 moir concludes with or contains a graphic formula, it is clearly the 

 duty of some practical teacher of recognized ability to answer by 

 actual trial the important question, Can such formulae be used as of 

 real assistance to the analytical instructor ? Mr. Valentin has made 

 the experiment, and responds in the affirmative. 



The first part of the work (128 pages) is taken up with a varied 

 series of one hundred operations, which become successively more 

 complex in their meaning as we proceed. On each occasion the 

 teacher stands, as it were, at the student's side, points out what is 

 to be observed and what is extraneous, and then exhausts the phe- 

 nomena of their inferences. The entire book is singularly and admi- 

 rably argumentative in this manner. Much of its first portion would 

 furnish, and no doubt will be made to furnish, material of a high 

 class for the earlier lectures of a chemical course, more especially 

 when we hear in mind the numerous and well-executed engravings 

 by which it is illustrated. Where not original, these have been 

 taken from the best sources. By the time the student has reached 

 Part II. he may fairly be supposed to understand all the ordinary 

 operations of analysis, the management of apparatus and reagents, 

 the transference and manipulation of gases ; but he will have, in 



