60 



KNOWLEDGE. 



February, 1915. 



paid for it as highly as if he had not. A clergyman makes a 

 mistake, and it is discovered only in the ne.xt world. But 

 if an analyst makes a mistake, he is condemned. He has 

 committed the unpardonable sin." 



The difference between the analyst and the other pro- 

 fessional inen cited is that he makes assertions as to matters 

 of fact, whereas the physician, lawyer, and clergymen may 

 express opinions. If the analyst can be shown to be wrong, 

 this mistake is regarded by the public as of the same kind 

 as that of the dentist who pulls out the wrong tooth, or 

 the surgeon who makes a cut in the wrong place. In both 

 of these instances a court would award damages to the 

 victim. 



C. A. M. 



Tlie Elements of Chemistry. — By H. L. Bassett, B.A., B.Sc. 

 With an introduction by Professor W. J. Pope, M.A., 

 F.R.S. 368 pages. 32 illustrations. 7-in. x 5-in. 



(Crosby Lockwood & Son. Price 4/6.) 



Professor Pope points out very cogently in his intro- 

 duction that most scientific professions demand some ele- 

 mentary knowledge of chemistry in more than one of its 

 divisions, although a student's work may subsequently have 

 only an indirect connection with the science. It is with the 

 needs of the medical student more especially in view that this 

 book has been written, and it should pro\-e of the greatest 

 ser\dce to those who are preparing for the examinations 

 of the Conjoint Board. It is divided into the four sections : 

 General and Physical Chemistry, Inorganic Chemistry, 

 Organic Chemistry, and Practical Chemistry. Obviously 

 it is impossible within so limited a space to go very tho- 

 roughly into any of these branches, but the book gives a 

 useful summary, and for those who are not working for 

 examinations it could well serve as an inti'oduction to larger 

 treatises. It would be an advantage, from one point of 

 view, if the practical work were distributed throughout the 

 other sections, instead of being put at the end of the book. 

 The theory of chemistry should be supported, not crowned, 

 by experimental work. 



C. A. M. 



The Chemistry of the Radio-Elements (Part I). — By Frederick 

 SoDDY, F.R.S. 151 pages. 3 figures. 8|-in. x 5|-in. 



(Longmans, Green & Co. Price 4 .'- net.) 



Part II of this book was issued in 1914, as a result of 

 important advances then made ; to supply the demand 

 consequent on the interest created in the subject by those 

 advances, it has been necessary to publish a new edition 

 of Part I. The new edition has not only been brought up 

 to date, but has been enlarged, and almost completelv 

 rewritten. The fact that this new edition of Part I has 

 been called for is testimony that the scientific public has 

 realised to a great measure the advances that were outlined 

 in Part II. 



The book may be roughly divide:! into two halves, the 

 first of which deals with the general principles invol\-ed. 

 In the latter half the chemistry of the radio-elements is 

 described sj'stematically. With regard to the first half, 

 we feel sure that, to any reader who wishes to become 

 acquainted with the broad facts and principles of radio- 

 activity from the physical as well as the chemical stand- 

 point, no better summary could be recommended, provided 

 that he possesses a knowledge of chemical laws and of the 

 elementary facts of general science. The second half of the 

 book will be of greater use to the person engaged practically 

 in radio-active work, and the author's great experience 

 in this direction has enabled him to make this section of 

 the greatest value for use in the laboratory. 



The chapter on the " Adsorption, Electro-, and CoUoido- 

 Chemistry of the Radio-Elements " is exceptionally interest- 

 ing, and contains a number of suggestions for further 

 work. 



A. F. 



EVOLUTION. 



Mutual Aid : A Factor of Evolution. — By P. Kropotkin. 

 Popular Edition. 240 pages. 7i-in. x 5-in. 



(William Heinemann. Price 1 /- net.) 



The issue of a cheap popular edition of Prince Kropotkin's 

 well-known book, " Mutual Aid," is particularly to the 

 point at the present moment. It has been suggested that 

 the wholesale destruction of life among non-combatants 

 and the pillage of their means of subsistence in the present 

 war is part of the ordinary " struggle for the existence." 

 Prince Kropotkin's book, dealing as it does with mutual 

 aid amongst human beings, supports the protest which has 

 been made against such an abuse of Darwin's terminology. 



For those who are unfamiliar with " Mutual Aid " we may 

 add that it describes co-operation among animals, among 

 savages and barbarians, and with the craft guilds of the 

 mediaeval city, in addition to more modern instances. 



W. M. W. 



FARMING. 



Impurities of Agricultural Seed, with a Description of com- 

 monly occurring Weed Seeds and a Guide to their Idoitification. 

 — By S. T. Parkinson, B.Sc, and G. Smith, B.Sc. 

 105 pages. 152 illustrations. 7|-in. x5-in. 



(Headley Brothers. Price 3 /- net.) 



In few walks of life is the necessity for organised know- 

 ledge at the present time greater than in farming. The 

 agriculturist has learnt, or is beginning to learn, that in 

 the case of many plant diseases there is no cure, and that 

 he must rely entirely upon prevention. Though weeds 

 can be got rid of, the task is often a difficult one, and here 

 it is possible to avoid one common cause of their intro- 

 duction. This is by taking care not to sow seed which is 

 impure. Before, however, a farmer can tell what weed- 

 seeds occur among those which he is buying, he must have 

 some knowledge of the subject. Messrs. Parkinson and 

 Smith are therefore to be congratulated warmly on having 

 produced a veiy useful book. The introduction is very 

 concisely and simply written, while the large number of 

 reproductions of photographs of weed-seeds, of which we 

 are courteously permitted to reproduce a few in Figures 

 50 to 58, will be a very great help, not only to the farmer, 

 but to the seed specialist. There are one hundred and fifty- 

 two of them in all, and each is accompanied by a brief 

 description giving the size of the seed in fractions of an 

 inch and in millimetres. 



W. M. W. 



GEOLOGY. 



Engineering Geology. — By H. Ries and T. L. Watson. 

 672 pages. 104 plates. 225 figures. 9-in. x 6-in. 



(J. Wilev & Sons, New York ; Chapman & Hall, London. 

 Price 17/- net.) 



Geological conditions affect many engineering operations, 

 especially in railway construction, tunnel driving, reservoir 

 building, and works for the prevention of coast erosion, 

 improvement of rivers, and water supply. Geological con- 

 siderations also affect the selection of building stones, road 

 metals, cement materials, and clays, as well as the materials 

 such as coals and ore deposits, the mining of which has long 

 been recognised to have a geological basis. There has long 

 been a need for a work dealing with geology from this 

 practical point of view in its relation to various phases of 

 industrial activity. The book under review suppUes 

 this need very satisfactorily. The authors throughout 

 emphasise the practical application to engineering of all the 

 topics treated. The book is intended primarily for civil 

 engineers, but it will be found of considerable value to others 

 interested in applied geology. 



The first three chapters deal compactly but quite 

 effectively with the mineralogy and petrology necessary to 

 complete comprehension of the subject. They are followed 

 by chapters deahng with structural features and meta- 



