October 27, 1923] 



NA TURE 



617 



11 great possibilities of improvement in quality of seed 

 that might be brought about by a judicious application 

 of the principles of plant breeding. 



Maize would appear to have been much valued in 

 aboriginal America, but with the great increase in 

 colonisation which followed the voyage of the Mayflower 

 it has steadily increased in importance until now the 

 United States produce three-quarters of the total world- 

 crop. 



A special feature of the book is the excellence of 

 some of the original text figures, which are both clearly 

 drawn and well reproduced, being among the best 

 hitherto published for this plant. The aim of the book, 

 with others in the same series, is to reach the educated 

 layman as well as the specialist, and the volume offers a 

 useful and interesting resume of the subject dealt with. 



Supplying Britain's Meat. By G. E. Putnam. Pp. 

 169 + 16 plates. (London, Calcutta and Sydney: 

 G. G. Harrap and Co., Ltd., 1923.) 55. net. 



Mr. G. E. Putnam is the consulting economist to Swift 

 and Company, Chicago. Of the seven chapters of his 

 book, the first three, and possibly the sixth, deal with 

 the subject selected for the title of the book. The 

 remainder are devoted to an economic justification of 

 the big-scale United States businesses dealing with the 

 distribution of meat and meat products, and to a 

 defence of their conduct as stated in the official reports 

 of American commissions, and the large volume of 

 unofficial criticism from the American public. 



From the British point of view, the most significant 

 fact is that only 60 per cent, of the beef, and 50 per 

 cent, of the mutton consumed in Great Britain is home- 

 grown, and there seems little possibility of the home 

 ^applies even maintaining this proportion in the future. 

 The manner in which this deficiency in home supply 

 has been met by -Imperial and foreign shipments is 

 very well traced out. The sections dealing with the 

 distribution of imported meat contain a detailed 

 defence of the middlemen. The author believes that 

 they perform indispensable economic functions, and 

 further, their work cannot be done efficiently unless 

 they are units in an organisation in the closest touch 

 with the firms of meat exporters. 



Letters of a Radio-Engineer to his Son. By Jolin Mills. 

 Pp. vi + 265 + 12 plates. (London: G. Routledge 

 and Sons, Ltd., 1922.) 105. 6d. net. 



At the present time practically every student at a 

 technical college, and most school-boys, arc intensely 

 interested in radio communication. The author takes 

 advantage of this and writes a book in familiar language 

 as an introduction to understanding the latest develop- 

 ments of the art. He expends no time in describing 

 fluid theories or pith balls. He plunges at once into 

 describing protons and electrons and, provided his 

 reader coasents to follow him, shows what an essential 

 part they play in radio apparatus. How to measure 

 an " electron-stream " and " electron-moving-forces " 

 are simply described. Inductance and capacity, tuning 

 and resonance and the harmonics in the human voice 

 are explained. Broadcasting stations, trans- Atlantic 

 telephony and the telephone circuit with its amplifying 

 stations connecting New York and San Francisco are 

 also described. The author, who is a well-known 



NO. 2817, VOL. I 12] 



expert of the Western Electric Co., concludes by point- 

 ing out how excellently ordinary telephony and radio 

 telephony can be united so that the voice vibrations 

 can be carried over wires and across wide spaces before 

 they come to the receiver. The two methods use the 

 same general principles and much of the apparatus 

 used is common to both. 



Epping Forest. By E. N. Buxton. Ninth edition 

 revised. Pp. xiv + i82 4-6maps. (London: Edward 

 Stanford, 1923.) 2s. 6d. 



The ninth edition of this little book, which has been 

 out of print since 1915, is very welcome. It contains 

 a history of Epping Forest, with an account of the 

 topography, accompanied by several coloured maps. 

 Other chapters follow on the animals, birds, insects 

 and pond life of the forest area, as well as the trees, 

 flowering plants, mosses and fungi. A short chapter 

 gives an account of prehistoric man and the animals 

 he hunted. Another is devoted to the geology of the 

 district. A final chapter has been added on the 

 management of such a forest. It will no doubt be 

 found useful by students, naturalists and others who 

 visit Epping Forest and wish to know more of its 

 natural history. 



The Chemistry of the Inorganic Complex Compounds : 



an Introduction to Werner's Co-ordination Theory. 



By Prof. R. Schwarz. Authorised translation by 



Dr. L. W. Bass. Pp. x + 82. (New York: J. 



Wiley and Sons, Inc. ; London : Chapman and Hall, 



Ltd., 1923.) 85. 6d. net. 



This book is a translation from the German of an 



introduction to the study of co-ordination compounds. 



It is an excellent little book for the purpose, and even 



advanced workers in this branch of chemistry will 



find it of value on account of the fact that a reference 



to the original literature is given in the case of all the 



compounds that are referred to throughout the book. 



The form in which the book is issued is very attractive, 



and it should have a large circulation among English 



readers. 



Handbook of Steel Erection. By M. C. Bland. Pp. 



ix-H24i. (London: McGraw-Hill Publishing Co., 



Ltd., 1923.) 12s. 6d. 

 There are but few books dealing with this subject, 

 and for the most part treatises on structures do not give 

 adequate treatment to the methods of erection. The 

 volume before us gives both descriptions of these 

 methods and also the calculations involved in deter- 

 mining the strengths of the appliances used. Civil 

 engineering students will find the book a useful supple- 

 ment to their text-books on structures. 



The Unconscious : an Introduction to Freudian Psycho- 

 logy. By Israel Levine. Pp. 215. (London : 

 Leonard Parsons, Ltd., 1923.) 7^. 6d. net. 

 An excellent short account of the Freudian theory 

 in its general philosophical aspect. The author finds 

 no need to force on the reader unplea.sant descriptions 

 of particular neuroses, and he treats the whole concept 

 of the unconscious as a mctapsychology. Its relation 

 to older classical conceptions and to modem rival 

 theories is briefly but quite clearly indicated. 



