io8 



NATURE 



\Dec. lo, 1874 



the common gases, such as oxygen, hydrogen, carbon 

 dioxide, nitric oxide, ammonia, carbon monoxide, chlo- 

 rine, and hydrochloric acid. After the preparation of these 

 gases the student is made acquainted with the process of 

 distillation as applied to water, and to the preparation of 

 nitric acid. The entire absence of theory from this sec- 

 tion is perhaps to be regretted. Although a student may 

 have previously read the reactions that occur in the 

 preparation of the various gases, there is no more favour- 

 able opportunity for impressing these upon the mind than 

 at the time of performing the experiment for himself. If 

 beginners were always to ask themselves, What chemical 

 change is going to occur in this tube or flask ? and then 

 write down the equation, the knowledge gained would not 

 be of that purely mechanical nature which the boring 

 of corks and bending of glass^ tubes alone tend to 

 engender. 



Section II. treats of the preparation and use of the 

 apparatus required for analysis. Bunsen's burner, the 

 spirit lamp, blowpipe, bending and cutting of glass tubing, 

 cork-boring, and other practical minuti^, are here de- 

 scribed, and some valuable hints given on the use of the 

 various pieces of apparatus employed by the student of 

 analysis. 



The details of glass-working seem to us somewhat mis- 

 placed here. Tubing must be bent, and corks bored and 

 fitted into flasks, tubes, &c., in the course of fitting up the 

 apparatus for the preparation of gases ; so that it would 

 be more logical if this section were made to precede 

 Section I. We miss from this section, also, any reference 

 to the excellent blowpipes made on Herapath's principle, 

 now so generally employed in our laboratories. Students 

 who have once used these blowpipes soon abandon the 

 old mouth blowpipe figured in the present woik. 



The various operations connected with analysis are 

 described and experimentally illustrated in Section III. 

 Here the student is made acquainted with the processes 

 of solution, crystallisation, filtration, evaporation, pre- 

 cipitation, ignition, &c., and the way is thus prepared for 

 the next, section, wherein are given the analytical reac- 

 tions of the more commonly occurring metals. The 

 author adopts the usual analytical classification ; this 

 section, indeed, offers but little scope for originality, and 

 we find the same tests and reactions which are to be 

 found in the works of Fresenius and Rose, and the many 

 volumes of their imitators. The modicum of theory 

 relating to the use of symbols and the expression of 

 reactions as equations, which we should have preferred to 

 see in an earlier portion of the book, finds place at the 

 beginning of the present section. We are glad to see 

 equations given for most of the reactions of the metals ; 

 too often the words " white pp." or " black pp." go down 

 into the student's note-book without any idea of what 

 chemical change has occurred having entered into his 

 mind. After the reactions of the metals of each group, 

 tables are given showing the characteristic differences 

 between the members of that group and the methods to 

 be pursued in the cases of mixtures. This plan of tabu- 

 lating the diffeiences between the various metals of a 

 group is a special feature of the present work ; in this 

 country the idea seems to have been first introduced into 

 Galloway's " Manual of Qualitative Analysis," and its 

 adoption by Mr. Clowes is to be highly commended. 



When a student is made to go through a long series of 

 reactions with closely allied metals, he is apt to overlook 

 the points in which they differ unless these arc specially 

 pointed out to him. It is as though a zoologist were to 

 give lengthy descriptions of two closely allied species of a 

 genus without any reference to their differential charac- 

 ters. The reactions of the acids, inorganic and organic, 

 follow those of the metals. 



Passing on to Section V., we find the ordinary course 

 of analysis pursued in [the case of a simple salt contain- 

 ing one base and one acid, the tables being modified to 

 meet the cases of solids and liquids, acid or alkaline. 



In the following section, containing the complete 

 course of analytical tables ,for complex mi.xtures, we 

 recognise the well-known tables compiled, we believe, by 

 Dr. Hofmann for the Royal College of Chemistry. The 

 phosphate table devised by Mr. Valentin has been intro- 

 duced with the author's permission. The present work 

 offers, therefore, as good an analytical course as is to be 

 found in any of our text-books, the type in which the 

 tables are printed is decidedly small, but the plan of 

 printing them across instead of along the page, offers, as 

 the author justly ^claims, a distinct advantage. 



Section VII. is devoted to a description of apparatus 

 and reagents used in the analytical course. The methods 

 given for constructing pieces of apparatus for general 

 use, and the preparation of special reagents such as 

 hydrofiuosilicic acid, will be found valuable adjuncts to 

 the book. The appendix contains a list of elements with 

 their symbols and atomic weights, formulre for the con- 

 version of thermometric scales, and tables of weights and 

 measures. 



It will perhaps be better not to inquire into the raison 

 (Tctrc of the work an outline of which we have now 

 laid before our readers. It may be asked why the student 

 should not be made acquainted with the method of 

 preparation and properties of nitrogen, nitrous oxide, 

 phosphoretted hydrogen, and cyanogen ; these gases 

 surely are of sufficient chemical importance to justify a 

 knowledge of their properties, and their preparation 

 cannot but furnish good exercise for the manipulatory 

 skill of a student. The list of corrigenda is certainly 

 alarming, and we hope the author will have the oppor- 

 tunity of correcting these in a later edition. 



The defects we have had occasion to point out in the 

 course of this notice are not, it must be admitted, of a 

 very grave character. We do not scruple to say that the 

 author has performed his task on the whole well, and we 

 should have no hesitation in putting the book into the 

 hands of the chemical student. 



The present volume may, in fact, be taken as a fair 

 average specimen of the systems of teaching practical 

 chemistry followed in this country, and as such we shall 

 venture a few remarks upon it in concluding. In the first 

 place, we should like to see a little more -fir/V/za' introduced 

 into our courses of analysis— something of the nature of 

 a chemical key to the analytical tables is in our opinion 

 a desideratum. At present the student generally follows 

 blindly the instructions given in the tables ; he dissolves, 

 precipitates, or filters without any regard to the chemical 

 reactions occurring at the various stages. It is similar to 

 the old system of learning off a problem of Euclid by 

 heart, without entering into the reasoning— change the 



