i6o 



NA TURE 



{jfune 28, 1877 



of geology, such as Dr. Hermann Credner's " Elemente 

 der Geologie " and Dr. F. von Hochstetter's " Die 

 5rde nach ihrer Zusammensetzung, ihrem Bau, und ihrer 

 Bildung," the necessity of this term physiography is 

 admitted and its use justified. Like the term " biology," 

 that of " physiography " may not improbably meet with 

 some opposition on its first introduction, but as the im- 

 portance and connection of the branches of knowledge 

 which it embraces become more widely appreciated, the 

 necessity and convenience of the name will doubtless 

 make themselves very generally felt. In conclusion, we 

 cannot part from the little book which has prompted these 

 remarks without taking the opportunity of congratulating 

 the author on his success in presenting to the public, in a 

 form at once compendious and popular, the outhnes of 

 this very important branch of science. J. W. J. 



THE LABORATORY GUIDE 



A Manual of Practical Chemistry for Colleges and Schools. 

 Specially Arranged for Agricultural Students. By 

 Arthur Herbert Chuich, M.A., Professor of Chemistry 

 in the Agricultural College, Cirencester. Foutth Edition, 

 revised. (London: John Van Voorst, 1877.) 



'"PHE fact that Prof. Church's "Laboratory Guide" 

 jL has reached a fourth edition is a proof that the 

 work has been found useful by that class of students for 

 whom it is specially arranged. Notwithstanding this fact 

 we cannot regard the book as occupying other than a 

 second-rate position in the literature of applied che- 

 mistry. The aim of the " Guide " is (i) to place before 

 the student a series of lessons in chemical manipulation 

 in working through which he shall obtain a practical 

 knowledge of " some of the chief truths learnt during the 

 course of lectures on inorganic or mineral chemistry ; " 



(2) to instruct the student in qualitative analysis with 

 especial reference to the analysis of agricultural products ; 



(3) to lay before the more advanced student a number of 

 processes for the quantitative analysis of agricultural sub- 

 stances, food stuffs, manures, &c. The first part of the 

 work comprises a number of fairly well chosen examples in 

 chemical manipulation, preparation of gases, and exami- 

 nation of solid substances. What we should most object 

 to in this portion of the " Guide" is want of method. A 

 few blowpipe experiments are introduced here and there, 

 followed, perhaps, by a short description of one or two 

 rouo-h experiments illustrative of the manufacture of 

 superphosphates ; these are succeeded by desultory tests 

 for sugar in milk, by casual semi-quantitative experiments 

 on bread, and so on. To a student without any know- 

 ledge of chemistry such a course as that sketched ia the 

 first part of the " Guide " may be of use, although we 

 think more care would require to be shown in the selection 

 of experiments ; but the book assumes that the student 

 accompanies his practical work by attendance on lectures ; 

 surely then the practical course ought, from its very com- 

 mencementjto be sy stematic and progressive. The directions 

 given in each lesson are, as a rule, too meagre ; without the 

 constant superintendence of a teacher we doubt whether 

 the beginner in practical work could make much progress. 

 In some cases the directions are so vague and inexact as 

 to be positively misleading : witness the method for de- 



tecting alum in bread (p. 43). Part II. treating of quali- 

 tative analysis has the same failings as Part I. ; it is not 

 exact and definite. The author, in his introduction, 

 especially announces that the work is limited in its aim, 

 so that we cannot find fault with him for not including 

 tests for all the metals ; but so far as it goes the informa- 

 tion given, and the system of teaching pursued, should 

 have been definite, condensed, and such as would train 

 the student in habits of accuracy. No doubt the reac- 

 tions detailed are true so far as they go ; the schemes of 

 analysis are tolerably good, yet there is about it all a 

 slipshod appearance which stamps the work with an 

 unsatisfactory character. 



The processes of quantitative analysis are chiefly such 

 as are required in the examination of agricultural pro- 

 ducts, and substances used in manufacturing manures, of 

 a few leading food stuffs, of soils, and of waters. As the 

 author has not wished to produce a large work, he has 

 limited himself to a description of methods of analysis 

 "intended only for the particular case mentioned ; " these 

 processes " may fail if ... . other substances be present 

 than those here supposed." We cannot help thinking 

 that this is exactly what he ought not to have done ; if 

 the book is to be a guide to the student, if it does not 

 pretend to the place of an encyclopaedic reference book, 

 then processes oi general applicability, should have been 

 selected, processes which would illustrate the application 

 of the general principles of analysis, not processes which 

 the student is to learn by rote, and which he will therefore 

 come to regard in much the same light as that in which 

 the cook views her book of receipts. Many of the pro- 

 cesses, regarded simply as prescriptions, are faulty or 

 very meagre. Who would apply the volumetric Uranium 

 method for determining phosphates in the manner de- 

 scribed on pp. 157, 158? Aided only by the description 

 of the volumetric method for determining chlorine given 

 on pp. 159, 160, v/ho could ever hope to perform an exact 

 estimation of that element? From what is said on p. 150 

 one would suppose that "reduced phosphates" can be 

 readily determined with something like accuracy. Th 

 report of the British Association Committee has shown 

 that no method for even approximately determining these 

 phosphates has as yet been introduced. 



The processes for the analysis of milk, cheese, and 

 butter are extremely meagre. Now that we are possessed 

 of really good and reliable methods for analysing these 

 food stuffs, the introduction into a manual of vague and 

 sketchy methods is almost worse than the omission of all 

 methods, whether good or bad. 



One point there is in which Prof. Church deserves all 

 praise, namely, the employment of a systematic nomen- 

 clature. The system adopted is that first employed in the 

 works of Roscoe, and of Harcourt and Madan, and now 

 adopted in the Journal of the Chemical Society, in Watts's 

 Dictionary, and in most of the modern treatises. This 

 system, although not slavishly bound down by rule — 

 although it allows one to say sulphate of zinc as well as 

 zincic sulpliate — is founded on certain definite ideas, and 

 has, at the same time, shown itself capable of expansion 

 with the needs of an increasing science. 



The system is, moreover, nearly identical with that 

 employed by the German chemists. Prof. Church has 

 done well in making use of it. 



