June i, 1916] 



NATURE 



279 



largely descriptively and with the help of numerical 

 illustrations and simple experiments. The print- 

 ing and diagrams are clear. But one may be 

 allowed to ask why here, as in many other books, 

 the so-called laws of friction deduced for dry sur- 

 faces and low intensities of pressure are given 

 without a hint that in most cases they are more 

 disobeyed than obeyed? Also, is such a very 

 roundabout way of finding the work of a fluid 

 pressure (Fig. 121) really helpful to a student? 



(3) Mr. Taggart's book is similar to the fore- 

 going, but it is more specialised, the illustrations 

 being taken from textile machinery. It is more 

 original, therefore, and is likely to be of service 

 to textile workers, both in explanation of the 

 machines they use and in familiarising them with 

 some of the technics of the industry. 



OVR BOOKSHELF. 



On the Relation of Imports to Exports : A Study 

 of the Basis of a New National and Imperial 

 Policy. By J. Taylor Peddie. Second edition 

 (enlarged). Pp. xxiv + 148. (London: Long- 

 mans, Green and Co., 1916.) Price 55. net. 



Mr. Taylor Peddie 's book is written in favour 

 of what he calls National Economics. "National 

 Economics," he says, " to be based on freedom 

 ■of trade, must come under the heading of low 

 tariff duties, for high tariff duties are protective." 

 Now, if low tariffs do not protect, what is their 

 object? In his third essay Mr. Taylor Peddie 

 attempts to answer this question. " British 

 manufacturers . . . will have to submit ... to a 

 heavy income tax and other heavy direct taxation. 

 ... Is it, then, an equality of rights that Ameri- 

 can manufacturers . . . should in future be 

 allowed to enter into free competition with our 

 own oroductions? " Mr. Taylor Peddie has, 

 in fact, rediscovered, repainted, and reclothed that 

 ancient figure of fun, the mid-nineteenth-century 

 French Free Trade school's Scientific Tariff, and, 

 with the true artist's "temperament," he has 

 fallen deeply in love with it ! 



True, his tariffs lack something in scientific pre- 

 cision, for he has found a special magic in the 

 figure 17I per cent., and no duty must exceed that 

 amount. But their achievements more than com- 

 pensate for all purely academic desiderata. His 

 "low tariffs," apparently, are to counterbalance 

 the adverse balance of trade, although (p. 42) he 

 assures us that Free Trade has not produced that 

 adverse balance. His " low tariffs " are to have no 

 effect on prices, but to restrict imports (without 

 protecting), increase the national productive 

 capacity, the revenues of the State, and the distri- 

 bution of wages, and although not affecting prices 

 (p. 3g) we can sell cheaper (p. 40). Mr. Taylor 

 Peddie is, indeed, to be congratulated on his per- 

 versely paradoxical panacea. 



On p. 98 we are told that "we shall never be 

 able to destroy German industrialism by allowing 

 National Economic questions to be discussed in the 

 abstract or as platitudes." If "National Econo- 

 mics " are really to be framed with the object of 



NO. 2431, VOL. 97] 



destroying industrialism, we are perhaps justified 

 in hoping that they will quickly become what Mr. 

 Taylor Peddie believes the history of political 

 economy for the main part to be — "a record of 

 absurd and justly exploded opinions." A. L. 



A Manual on Explosives. By Albert R. J. Ramsey 

 and H. Claude Weston. Pp. xi+ii6. (Lon- 

 don: George Routledge and Sons, Ltd., 1916.) 

 Price 15. net. 



This little manual is intended to furnish to the 

 munition worker, as well as to the general reader, 

 concise information on the nature of explosives 

 and on their manufacture, and further to empha- 

 sise the very important part which explosives play 

 in the sphere of modern engineering. It is cer- 

 tainly an excellent little primer. Particularly good 

 is the description of the manufacture of nitro- 

 cellulose, nitro-glycerin, and the modern high 

 explosives, the text being illustrated by excellent 

 diagrammatic representations of the various plants 

 employed. The authors have shown considerable 

 discretion in the allotment of space to the different 

 explosives, but more might well have been devoted 

 to propellants. Smokeless powers, other than 

 cordite, scarcely receive mention. The description 

 of the manufacture of cordite is very brief, and it 

 is a pity the authors give only the composition of 

 Mark I. cordite, which, through the serious 

 erosion it produced in the guns, was superseded 

 some years ago by M.D. cordite, containing less 

 nitro-glycerin. 



A short chapter is devoted to fuses and detona- 

 tors, another to the application of explosives, 

 some interesting examples of engineering appli- 

 cations being given. A valuable chapter is one 

 on " Industrial Poisoning among Explosive 

 Workers and its Prevention," in which the authors 

 deal with the symptoms by which poisoning may 

 be recognised, the general lines of first-aid treat- 

 ment, and enumerate some of the simple precau- 

 tions which should be adopted to minimise risk 

 of poisoning. Such chemistry as is necessary to 

 follow the various processes and relating to the 

 composition of explosives is very clearly set out. 

 and altogether the book admirably fulBIs the 

 intentions of the authors. 



Yorkshire's Contribution to Science — with a Biblio- 

 graphy of Natural History Publications. By T. 

 Sheppard. Pp. 233. (London : A. Brown and 

 Sons, Ltd., 1916.) Price 55. net. 



The object of this volume is to provide students 

 of the natural history of Yorkshire with a guide 

 to all sources of information likely to be of service 

 to them. Many workers in biological and geologi- 

 cal science will be grateful to Mr. Sheppard for 

 the particulars he has brought together about 

 Yorkshire periodical publications dealing with 

 natural history, Yorkshire scientific magazines 

 now extinct, and Yorkshire topographical and 

 general magazines. The particulars concerning 

 other British scientific journals and societies and 

 the list of works of reference add to the complete- 

 ness of the volume. 



