352 



NATURE 



[Decembi^r 4, 19 19 



gust those who know the brilliant gills of some 

 who are thus afflicted. He states categorically 

 that the mental improvement clue to education is 

 transmitted to offspring, and recommends late 

 marriage of the highly educated in order that 

 the effects of education may be more fully handed 

 on. And neither Prof. Richet nor Prof. Lloyd 

 Morgan seems to realise the extreme difficulty of 

 eliminating an undesirable character if it is re- 

 cessive in inheritance. In a stable population, if 

 I per cent, show a recessive character, 18 per 

 cent, will bear this character concealed by the 

 corresponding dominant, and by preventing the 

 reproduction of the i per cent, in which the re- 

 cessive is homozygous, only very slow progress 

 will be made in eliminating it. Prof. I^ichet is 

 an enthusiast for eugenics, and has written an 

 entertaining book, but one which is scarcely suffi- 

 cientlv abreast of modern work on heredity. 



L. D. 



Oim BOOKSHELF. 

 Essays in Common-sense Philosophy. By 



C. E. M. Joad. Pp. 252. (London : The 



Swarthmore Press, Ltd., 1919.) Price 8,';. 6d. 



net. 

 If any man of science, perplexed at the disturb- 

 ing challenge which philosophy throws down to 

 the assumptions as to plain matter of fact on 

 which science rests, wants comfort and support 

 for his intellectual framework from within philo- 

 sophy itself, he will find and certainly enjoy 

 it in the delightfully clear essays of Mr. Joad. 

 It is a somewhat unusual thing for a young writer 

 to make his debut in philosophy by rejecting every 

 temptation to paradox and any attempt to startle 

 the "plain man," and setting himself the ap- 

 parently easy but really very difficult task of con- 

 vincing- the " plain man " that his views about the 

 universe are not likely to be very far removed 

 from truth. Yet this is what Mr. Joad sets out 

 to do. 



Mr. Joad is not a very trustworthy guide when 

 he discusses famous philosophical theories. He 

 adopts too easy a classification, with the conse- 

 quence that we find ourselves in strange company. 

 All philosophers, past and present, are in his 

 view representationists, solipsists, or realists. 

 But this does not in the least spoil our 

 enjoyment of the concise and easy way in which 

 the writer finds himself at home in philosophy, of 

 the keenness of his wit, and of the dexterity of 

 his cut and thrust. There is only one of us who 

 comes in for unstinted praise — Prof. Dav/es Hicks 

 — and w'e believe he does not recognise his theory 

 in Mr. Joad's exposition. The rest of us — Berg- 

 sonians, pragmatists, absolutists — are all alike 

 well trounced. 



There is one thing in Mr. Joad's own view, 

 however, which is very puzzling, not to say dis- 

 concerting. He tells us that sensible objects exist 

 "very much" as we know them. But why not 

 altogether so? If there is any difference at all, 

 whv is he so confident it can only be a very little 

 one? H. W. C. 



NO. 2614, VOL. 104] 



Modern Engineering Workshop Practice: A 

 Text-hook for the Use of Engineering Students, 

 Apprentices, and Engineers engaged in Prac- 

 tical Work. By Herbert Thompson. (Griffin's 

 Scientific Text-books.) Pp. xi + 328. (London: 

 Charles Griffin and Co., Ltd., 1919.) Price 95. net. 

 This book is an attempt to give a fairly com- 

 prehensive view of modern engineering workshop 

 practice, and includes sections dealing with 

 general methods and machines, and others deal- 

 ing with special processes and machines, such as 

 turret lathes, spiral milling, grinding, hardening, 

 tempering, annealing, autogenous and thermit 

 welding, and soldering and brazing. The author 

 is quite at home in these branches. The descrip- 

 tions are clear, and whilst many of the illustra- 

 tions are half-tone reproductions of photographs 

 of machines and appliances, there is a sufficient 

 number of line drawings to enable the reader to 

 understand the construction. The author is not 

 so happy in chap, i., which deals with materials. 

 Thus, on p. 3 we read, under the paragraph head- 

 ing "Malleable-iron Castings" : "If an iron cast- 

 ing, made out of the right kind of pig iroi, be 

 heated to a red heat in an iron box surrounded 

 by some carbonaceous material for from 12 to 

 24 hours, the surface of the material becomes con- 

 verted into a form of steel. The casting then 

 has lost its extreme brittleness, and becomes more 

 or less malleable. The castings are generally em- 

 bedded in red haematite." In view of this state- 

 ment, it is of interest to note that later on (p. 229), 

 in dealing with case-hardening, the author shows 

 that his knowledge is sound, as regards both the 

 process and the changes which take place during 

 the progress of case-hardening. Despite blem- 

 ishes of this kind, the young engineering student 

 will find much that is instructive and of interest 

 in the book. 



Science and War: The Rede Lecture, 1919 By 

 the Rt. Hon. Lord Moulton. Pp. 59. (Cam- 

 bridge : At the LTniversity Press, 1919-) Price 

 25. 6d. net. 

 Lord Moulton's lecture gives a striking picture 

 of the manner in which the methods of warfare 

 have been transformed by the application to mili- 

 tary purposes of the results of the rapid growth 

 of chemical and physical knowledge and the 

 advances in engineering and medical science 

 during the last half-century. Not unnaturally, a 

 considerable part of the discourse is devoted to 

 the subject of explosives, on which the lecturer 

 can speak with special authority, and the warn- 

 ing which he gives as to the importance of estab- 

 lishing the manufacture of nitric acid from atmo- 

 spheric nitrogen in this country is one that 

 deserves serious attention. Lord Moulton's final 

 conclusion is that man, "endowed with al 

 the powers that science has given him, will be 

 self-destructive unless his social instincts . . . 

 become sufficiently strong to induce him volun- 

 tarily to submit to those powers being fettered." 

 " It is easy to criticise the League of Nations, but 

 let us never forget that some combined action of 

 that type is necessary." 



