7o6 



NATURE 



[February 24, 19 1() 



result is eminently satisfactory. The reality which is 

 given to the study so quickens the boys' interest that 

 their work is much better done, and about one-fifth 

 of the time usually given to the study is enough to 

 bring them up to the usual standard of the open 

 scholarship examinations. But the chief benefit is the 

 effect on ordinary boys in the earlier stages, who can 

 take pleasure and pride in their work when they feel 

 able to use it. We have " Latin teas," Latin plays, 

 and if you choose to address them in Latin on the 

 playing'field they will be pleased to respond. 



By this reform it is possible to meet the objections 

 usually, brought against Latin by scientific men ; for 

 it really does teach the language, and at a very 

 moderate cost of time; in the first four years only 

 three-quarters of an hour a dav. 



W. H. D. Rouse. 



Perse School House, Glebe Road, Cambridge, 

 February i6. 



THE author of "Submarines" is to be con- 

 gratulated on havingf produced a well-written 

 book upon a subject which has become of the 

 greatest interest to a large world of readers. He 

 tells us that this is not a technical book, and a 

 doubt might aiise lest it should in consequence 

 be devoid of any clear or exact information, but 

 this is not the case. The subject is so new and is 

 so little understood that the excellent exposition 

 of the whole subject to be found in the pages will, 

 without doubt, command a large and immediate 

 success. It would • be difficult to expend the 

 moderate price of 35. ^d. to better account if 

 making a present to any boy with an active mind, 

 and the boy need not be so very young or the 

 mind so very active — it is not written for boys — 

 for the reader to be absorbed in interest. 



The book is not technical, i.e., difficulties of ship- 

 building design, metacentric heights at different 

 immersions are not considered. 1 he peculiar diffi- 

 culties in the design of engines are not discussed, 

 though allusion is made to some of the peculiar 

 features of the Diesel engine in particular. Neither 

 the optical problem of the periscope nor its solu- 

 tion is explained in relation to its optical niceties, 

 though, of course, it is discussed generally. 

 These widely differing features are referred to as 

 showing in what way the book is not technical, 

 and for the general interest of the subject as a 

 whole it is well that it is not technical, for there 

 is abundance of interest in the twenty chapters 

 as they stand, and a technical discussion of the 

 numerous items which go to build up the modern 

 submarine would be manifestly impossible. The 

 writer of this notice would only remark in this 

 connection that the account of the periscope would 

 be improved If the optics were a little more fully 

 indicated and if, in particular, the " all round eye " 

 periscope invented by Mr. Funnel and worked out 

 by Mr. Niblett and by Messrs. Aldis had its 

 optical principle more clearly explained. There 

 is an excellent photograph of the all round view 

 taken, not at sea, but in the middle of a street, 

 with a central circular empty patch in which it 



^ "Submarines: their Mechanism and Operatons." By F. A. Talbot. 

 Pp. x+274 (London : W. Heineniai.n, 1915.) Price 3J. td. net. 



I is proposed to present the direct ahead view un 

 I a larger scale (Fig. i). There is a photograph dl 

 the peculiar and special all round lens lookint; 

 something like a glass insulator for a piano castor, 

 but it is impossible to see how it works, and tin- 

 photograph of the admirable view obtained by it 

 use makes the insufficiency of the description tin 

 more tantalising. 



In a subject where there is so much secret \ 

 it is somewhat surprising to find so much inlm- 

 mation with respect to the German submarines, 

 but this the authoi obtained directly from tin 

 Krupp Company of Essen. He was also provided 



Fig. I. - I tic won. eiim •'aa-ruuiiu v.ew pen co c 



throughout ihe 360 degrees ot the circle. iTom "submarines," by 

 F. A. Talbot. (W. Heinemann.) 



with information by submarine builders in America, 

 and from these and other sources he has been 

 able to produce a large number of excellent pic- 

 tures. It is satisfactory to know that the veil of 

 secrecy surrounding the development of the sub- 

 marine in this country appears to be unusually, 

 impenetrable. 



The only misprint, or mis-writing of the nature 

 of a misprint, is on p. 50, where the pressure of 

 the sea-water at a certain depth is given as so 

 many pounds per square foot instead of pounds 

 per square inch. C. V. Boys. 



NO. 



2417, VOL. 96] 



