364 



NA TURE 



[Septemeer 23, 1Q09 



another's discoveries, and hinted that few of the latter 

 are worthy of acceptance. The main object of the 

 book is said to be to try to prove that " heat is 

 not a vibration of material, not even of aether," but 

 we search in vain for a clear alternative definition. 

 It is a difficult book to follow because of the entire 

 lack of order. The whole is an intricate mixture of 

 simple experimental facts, quotations from books on 

 many subjects, some of which are very remotely con- 

 nected with heat, and a large amount of astounding 

 new theory. Most of the ordinary phenomena in heat 

 are dealt with, and a chapter in defence of the British 

 systems of measurement is included. We can neither 

 recommend the book to beginners — for it would con- 

 fuse them — nor to those conversant with the subject — 

 for it would waste their time. 



(2) The two little books on practical science are for 

 use in elementary schools, and the authors claim that 

 the scheme has already been thoroughly tested with 

 success. Part i. consists of a series of exercises in 

 measurements of length, area, volume, weight, and 

 density. Part ii. contains rather more advanced exer- 

 cises on the same subjects, together with some on 

 atmospheric pressure and heat, and a suggested course 

 of woodwork. The exercises do not consist of detailed 

 instructions of what to do and expect, but require 

 some initiative on the part of the student. This is, 

 indeed, the intention of the authors, who hold the 

 view that the pupil should discover facts for himself. 

 Thus, some of the exercises simply consist of a series 

 of questions to be answered by making experiments. 

 The books, although cheap, are clearly printed, and 

 will probably be found to serve their purpose. 



(3) Dr. Xeesen has undertaken a difficult task in 

 dealing with such a large subject in so small a volume. 

 Nevertheless, most of the phenomena proper to the 

 various subjects are referred to, although briefly. 

 With a few exceptions, the book is non-mathematical, 

 and deals rather with the experimental side. The 

 reader, therefore, has no need of an advanced know- 

 ledge of physics, and it is doubtless advantageous 

 for such to study the different kinds of wave motion 

 together. Besides the subjects mentioned in the title, 

 there are several paragraphs on radioactivity, in which 

 the properties of the a, j3, and 7 rays are dealt with. 

 Many of the diagrams are poorly drawn and printed. 

 This is particularly unfortunate in a book dealing with 

 wave motion and geometrical optics. 



(4) Quite otherwise in this respect are the two text- 

 books of physics by Dr. Stewart. That on sound 

 especially should supply the much-felt need of an ele- 

 mentary treatment of that subject. Exception may 

 be taken to the definition of simple harmonic motion 

 as the projection on a diameter of the uniform 

 circular motion of a point, because it leads students 

 to believe in the existence of such a point in all cases 

 of simple harmonic motion. It is rather surprising, 

 also, to find Doppler's principle and the production of 

 beats not referred to, especially as the latter is so 

 commonly used as a method of estimating frequencies. 

 Omissions are the chief fault in these volumes, and 

 they are even more frequent in the part on light. 

 There is no treatment of microscopes and telescopes, 



NO. 20S2, VOL. 81] 



nor the methods of measuring the velocity of light. 

 These are surely not out of place even in an elementary 

 text-book. In reading this part alone it is noticeable 

 that the undulatory theory is not sufficiently insisted 

 upon, but this is compensated for by the fact that the 

 laws of refraction and reflection are proved according 

 to this theory in the volume on sound. On the whole, 

 however, the books are distinctly good, and the large 

 number of experiments suggested will no doubt serve 

 to demonstrate the principles involved. 

 1 



VOLUMETRIC CHEMICAL ANALYSIS. 

 A Manual of Vohimcfric Analysis. For the Use cf 

 Pharmacists, Sanitary and Food Chemists, as well 

 as for Students in these Branches. By Dr. H. W. 

 Schimpf. Fifth edition, revised and enlarged. Pp. 

 XX + 725 (New York: John Wiley and Sons; 

 London : Chapman and Hall, Ltd., 1909.) Price 

 21S. net. 



THE plan of this work is as follows : — First, the 

 general principles of volumetric chemical 

 analysis are explained and illustrated. Next, the 

 knowledge thus gained is applied to practice-work 

 upon the commoner inorganic elements and their chief 

 compounds, and upon certain organic acids. Finally, 

 two branches of specialised work are taken up — 

 namelv, the analysis of various food-stuffs and phar- 

 maceutical products — and the book concludes with a 

 few examples of gasometric analysis applied to articles, 

 met with in pharmacy and medicine. 



The treatment is generally fairly exhaustive, and 

 the descriptions lucid. Often, indeed, the author gives- 

 almost a superabundance of detail in explaining the 

 principles of the methods used. For example, he sup- 

 plies not only the equations involved, but frequently 

 the arithmetic as well. In the early part of the book 

 he appears to have in mind the vei-}- elementary 

 student, and is at some pains to explain such matters 

 as the law of definite proportions. This seems hardly 

 necessary in a book of this character. Knowledge of 

 the elemenlaiy principles on the part of the student 

 might well be taken for granted. In fact, the author 

 is scarcely consistent ; a page or two later on we find 

 ourselves talking of univalent and divalent compounds, 

 monobasic and dibasic acids, without previous ex- 

 planation of the terms. A reader who knows what 

 thev mean would not be likely to want an exposition 

 of the law of definite proportions. 



.\ very useful description of the properties of in- 

 dicators is contained in the fourth chapter. The 

 reactions involved are dealt with mainly as ionisatioi> 

 phenomena, but a brief explanation is given of the 

 chromophoric theory also. 



The special feature of the volume, however, is the 

 amount of attention devoted to the assaying of phar- 

 maceufical preparations, particularly alkaloidal drugs. 

 No fewer than a hundred and fourteen pages are 

 taken up with these, and the sections appear to have 

 been brought well abreast of modern practice. One 

 division treats of the general volumetric estimation of 

 alkaloids, explaining the principles, and describing 

 some of the newer methods, as well as those which 

 are older and betttr known. .Afterwards comes a 



