66o 



NATURE 



[January 20, 1921 



Our Bookshelf. 



Animal Ingenuity of To-day. By C. A. Ealand. 

 Pp. 313. (London : Seeley, Service, and Co., 

 Ltd., 192 1.) Price 7s. 6d. net. 



Mr. Ealand describes in a lively way the ingeni- 

 ous or apparently ingenious behaviour of a great 

 variety of animals, and we strongly recommend 

 his book of wonders to the young in years and to 

 the young in spirit. It deals with such matters 

 as the humble-bee's nest, the wasp that uses a 

 little pebble for beating down the soil closing the 

 entrance to its burrow, the animated honey-pots 

 of the honey-ants, the aquatic beetle that taps the 

 water-lily's store of air, the male water-bug called 

 Zaitha, which is made to carry the eggs, and the 

 male cuckoo 's abetting of his " paramour 's " foisting 

 of her egg into another bird's nest, for he takes 

 advantage of his likeness to a sparrowhawk to 

 distract attention from the "nefarious" deed. This 

 case of "mimicry" takes our breath away, and 

 we must rest awhile. But Mr. Ealand's book is 

 extraordinarily interesting, though he is some- 

 times not critical enough. There is a good account 

 of birds' nests and eggs, though we do not believe 

 in the woodcock's "all-too-conspicuous eggs." 

 With the usual withered leaves around them they 

 do not seem to us to be conspicuous at all. Of 

 courtships, migrations, modes of hunting, engin- 

 eering triumphs, parental care, and of the whole 

 gamut of animal behaviour, Mr. Ealand has vivid 

 illustrations to give, and we should like it all, both 

 old and new, without reserve, if he were a little 

 more careful. Let us give one example. As he 

 himself says : " Friendship between a crab and a 

 pond-mussel seems to savour of the improbable," 

 and we should think it did, for, friendsbio apart, 

 the pea-crab in question lives- in the sea. We 

 have referred to credulity and inaccuracy, but we 

 must make another criticism of what, after all, 

 we regard as a wholesome book. Ls it right and 

 proper to quote long passages within inverted 

 commas without telling us who wrote them ? The 

 illustrations of the book are very clever. 



Prospector's Field-hook and Guide. By H. S. 

 Osborn. Ninth edition, revised and enlarged 

 by M. W. von Bernewitz. Pp. xiii-t-364. 

 (London: Hodder and Stoughton, Ltd., 1920.) 

 Price 125. 6d. net. 



A QUANTITY of new material has been added to 

 this handbook since the last edition was published 

 in 1910. Some of it, particularly those portions 

 referring to the description of ore deposits and 

 ore-testing, has been drawn from the bulletins of 

 the United States Geological Survey and the 

 Bureau of Mines, and various publications of 

 schools of mines and the technical Press. Other 

 additions which have been made are lists 

 of outfits suitable for prospecting, fresh field 

 tests, notes on sampling, and a new chapter 

 dealing with alloy minerals. In face of the claim 

 that the new edition is thoroughly up-to-date, it 

 is curious to find " chloride of formyl " given in 

 the appendix as the chemical name for chloroform. 



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A glossary of more than twenty pages gives brief 

 explanations of the technical terms in use, and, 

 in addition, a very full index is provided. 



Dictionary of Explosives. By A. Marshall. Pp. 

 xiv-f 159. (London: J. and A. Churchill, 1920.) 

 Price 15s. net. 



This book is essentially a work of reference for 

 the specialist in explosives, and has little interest 

 for the general reader. It consists of three sec- 

 tions. The main section is descriptive, and 

 arranged alphabetically. This is prefaced by a list 

 of explosives classified according to the uses for 

 which they are intended, and followed by a list 

 of the separate ingredients showing the explosives 

 in which each is used. 



In the dictionary the composition and some of 

 the properties of a large number of explosives are 

 given, including many of foreign origin, but only 

 those explosives are dealt with which are, or have 

 been, in practical use in the industries. It is easy 

 to see that the author has been handicapped by 

 the reticence of explosives manufacturers with 

 regard to the composition of their products, only 

 about half the authorised explosives mentioned in 

 the 1914 Annual Report of H.M. Inspectors of 

 Explosives, for instance, being described. For the 

 same reason, many of the descriptions lack the 

 detail desirable in a work of this kind. 



A considerable amount of useful and accurate 

 information is, however, presented in a compact 

 and handy form. The book is well printed and 

 free from typographical errors. 



W. L. Turner. 



Report on the Quantum Theory of Spectra. By 

 Dr. L. Silberstein. Pp. iv-l-42. (London: 

 Adam Hilger, Ltd., 1920.) Price 5s. net. 



This small and unpretentious work is one of great 

 value. Many important developments in the ap- 

 plication of the quantum theory to spectra, 

 especially to the fine structure of spectrum 

 lines, have taken place during the last few years, 

 and these are almost entirely due to workers in 

 other countries. The literature of the subject is 

 very inaccessible to English readers, who find it 

 difficult to obtain any real idea of the fundamental 

 advances which have been made, or of the logical 

 suppositions on which such advances rest. Dr. 

 Silberstein would have done good service if he 

 had only collected together the original papers, in 

 translation, as they stand. He has, however, 

 done much more. The matter is presented as an 

 orderly scheme, and great discrimination has been 

 shown, so that there is nothing of real importance 

 omitted from the work. At the same time, the 

 author has modified the original treatment in many 

 respects, and apparently always to its advantage. 

 The work is especially noteworthy in that it gives 

 a clear view of the problems which still await 

 solution. We can give nothing but praise to this 

 book, and can recommend it without reserve to 

 those who are anxious to have a simple and not 

 very mathematical account of a subject which is 

 now fundamental in physical theory. 



