2 24 



NATURE 



[May 17, 191 7 



self certain properties of chalk and gypsum. 

 Experiment, in fact, is the keynote of the book. 

 The authors teach mainly by experiment, and 

 endeavour, as they put it, "to lead from fact to 

 fact in an interesting and logical sequence." This 

 setting of the student to " do things " straight 

 away will awaken his interest, if anything will ; 

 and the experiments are well devised to make him 

 absorb knowledge at his fingers' ends — the kind 

 of knowledge which comes to stay. Quantita- 

 tive experiments are introduced early in the 

 course, and even though these are, sometimes, 

 approximative only in the results, they have con- 

 siderable educative value. No special syllabus 

 has been followed, but the book treats of the in- 

 organic substances usually included in an elemen- 

 tary course. A chapter on technical processes at 

 the end, however, gives short accounts of some 

 classes of carbon compounds — oils, soaps, coal- 

 tar dyes, and perfumes ; and this adds to the 

 comprehensiveness of the volume. The descrip- 

 tion of the experiment with iron filings (p. 93) 

 needs revision, as also does "that with sodium 

 chloride and silver nitrate (p. 233, fifth line from 

 the bottom). Sulphuric acid, moreover, can 

 scarcelv act upon the formula of formic acid 

 (p. 180). 



(2) In this edition of Messrs. Clowes and Cole- 

 man's well-known work the subject-matter has 

 been increased and rearranged. For the informa- 

 tion of readers not familiar with the book it may 

 be said that Part ii., now under notice, deals with 

 elementary analytical chemistry, both qualitative 

 and quantitative. It is arranged in four divi- 

 sions. In the first, descriptions are given of the 

 reactions of the commonly occurring metals and 

 acid-radicles, together with methods for their 

 detection. This portion includes the usual 

 analytical tables, and forms the larger part of the 

 book. Volumetric analysis is dealt with in the 

 second division, and gravimetric determinations 

 in the third. Acidimetry, alkalimetry^ and deter- 

 minations by means of oxidation, reduction, and 

 precipitation operations are included in the volu- 

 metric processes ; whilst in the gravimetric section 

 the student is given exercises which initiate him 

 into the methods of estimating the common metals 

 and acids with the aid of the chemical balance. 

 In the fourth and concluding division directions 

 are given for the preparation of various classes of 

 inorganic compounds by operations involving 

 crystallisation, precipitation, sublimation, and dis- 

 tillation. The descriptions are lucid, and ,the 

 information generally trustworthy ; and no doubt 

 the volume will continue, to be a favourite text- 

 book with students. In the ideal text-book, how- 

 ever, the student would not be told (p. 216) to 

 "use i97'2 " as the atomic weight of platinum 

 for the purpose of correcting his results. Nor 

 would the ideal text-book show quite so much 

 small print, or be quite so economical of paper, as 

 the present volume, even in war-time. 



(3) Of Lunge's " Handbook " it must here 

 suffice to say that it comprises tables of general 

 chemical and physical data, such as molecular 

 weights, specific gravities, arid vapour densities, 



NO. 2481, VOL. 99] 



together with analytical methods used for the 

 control of the operations in various chemical in- 

 dustries, including the manufacture of sulphuric 

 acid, alkali, ammonia, coal-gas, and cement. In 

 the new edition the analytical factors have been 

 recalculated on the basis of the international 

 atomic weights for 1916, and the tables of specific 

 gravities have been revised, checked, and ex- 

 tended. The author's name is a guarantee that 

 the data are trustworthy and the methods judi- 

 ciously selected. 



(4) Is there any reason why an elementary 

 treatise on chemistry written " for rural schools " 

 should differ from the ordinary run of text-books 

 on the subject? The authors think there is, inas- 

 much as for such a treatise examples can be taken 

 from the farm, the garden, and the dairy to illus- 

 trate chemical principles. Thus the science can 

 be brought more directly home to the students, 

 and they are helped both to apply their knowledge 

 to farm work and the better to comprehend agri- 

 cultural literature. Copper sulphate, for instance, 

 is not treated merely as a collection of blue crys- 

 tals to be shown on the lecture-table. To the 

 authors' students it is the fungicide sprayed in 

 cornfields to kill charlock; it is the remedy for 

 foot-rot in sheep; it is the chief ingredient of the 

 Bordeaux mixture used for spraying potatoes. 

 These facts invest the "blue stone," which the 

 rural student is directed to prepare from copper 

 and Sulphuric acid, with a ver^' real interest for 

 him. In pursuance of this idea the illustrative 

 examples in the text are drawn from agriculture 

 rather than from manufactures. To make the 

 book serve not only as a foundation for the study 

 of pure chemistry, but also as an introduction to 

 agricultural chemistry, the authors have included 

 chapters on assimilation by plants, on proteins 

 and animal nutrition, on fermentation, and on the 

 constituents of soil. The collections of questions 

 provided are a useful feature, and the book will 

 be found very serviceable in rural schools. 



(5) Messrs. Cumming and Kay's, volume has 

 been revised in this, the second, edition, and addi- 

 tional methods of analysis have been included. 

 It is intended for university and college students, 

 for whom it provides a very satisfactory introduc- 

 tion to the various branches of quantitative 

 chemical analysis. The experiments described in- 

 clude simple electrolytic processes, gas analysis, 

 and molecular-weight determinations, as well as 

 the ordinary volumetric and gravimetric estima- 

 tions. The authors rightly emphasise the educa- 

 tive value of volumetric methods, and point out 

 the desirability of accustoming the student, from 

 the commencement, to the examination of sub- 

 stances the composition of which is unknown to 

 him. The directions they give are clear and 

 precise ; the examples are well chosen ; and every- 

 thing is done to inculcate cleanliness and accuracy 

 in manipulation. As an introduction to the art 

 and mystery of finding out "how much" of a 

 substance the experimenter is dealing with, and 

 of doing it with precision, this book can be un- 

 reservedlv recommended. 



C. S. 



