5o6 



NATURE 



[February i6, 191 i _ 



it when he gradually saw how astonishingly well it 

 did fit the facts. But he was certainly serious, beneath 

 his brilliant paradoxes; and, though a pariah in his 

 own day, he is now recognised as a true if somewhat 

 wayward and satirical genius. 



Stars shown to the Children. By Ellison Hawks. 



Pp. xii+ 119 + 49 plates. (London and Edinburgh: 



T. C. and E. C. Jack, n.d.) Price 25. 6d. net. 

 To give a clear, comprehensive insight into present- 

 day astronomy, in the " Shown to the Children " 

 series, was no light task, but in doing it Mr. Hawks 

 has approached nearly the ideal. To children " stars " 

 implies every extra-terrestrial orb, save the sun and 

 moon, and Mr. Hawks exhibits his ability to reach 

 the child even in his title. 



Thus the first twelve chapters describe the pheno- 

 mena of the solar system, and very brief chapters they 

 are. Yet the juvenile reader will become acquainted 

 with practically all the broad principles of our know- 

 ledge concerning the sun, moons, and planets, and 

 will find in the sky a new and inexhaustible interest. 



Nor can any important omission be pointed out in 

 the eight pages dealing with comets, yet the instruc- 

 tion is so interwoven with interesting " story " that 

 it is sure to be eagerlv assimilated. " Shooting stars," 

 in three pages, should lead to many a night's watch, 

 and produce a number of recruits for the still too 

 small army of meteor observers : the page or two 

 concerning the Green Flash and the Northern Lights 

 will probably not prove so fruitful. 



The stars themselves occupy seven chapters, thirty- 

 three pages, and only the most striking constellations 

 are described and drawn ; but the text is so replete 

 with interest and star-lore that the intelligent youth 

 will find himself forced to fill in the details. The 

 final chapters deal with the nebulae, the Milky Way, 

 and the appurtenances of an observatory, and should 

 complete the feeling of teing "at home " in the young 

 recruit. 



The forty-nine excellent illustrations will of them- 

 selves command the intelligent interest of most 

 children. In one or two places it would appear that 

 an effort has been made to m.eet the child, e.g. on 

 plate xxxiv. "The Mightv Hunter" need not have 

 been drawn as the pantomimic " Bowd Slasher," and 

 his belt should have been properly directed ; but with 

 so much to commend, these blemishes are relatively 

 few and insignificant. W. E. R. 



A Treatise on Electro-Metallurgy : Embracing the 

 Application of Electrolysis to the Plating, De- 

 positing, Smelting, and Refining of Various Metals, 

 and to the Reproduction of Printing Surfaces and 

 Art-work, etc. By W. G. McMillan. Third edition, 

 revised and enlarged. Revised by W. R. Cooper. 

 Pp. xv + 425. (London: Charles Griffm and Co., 

 Ltd., 1910.) Price 12s. 6d. net. 



The work of revising the excellent treatise of the late 

 Mr. W. G. McMillan has, on the whole, been admir- 

 ably done by Mr. Cooper, although there still remain 

 a few slight errors in the body of the work which 

 might have been corrected. For example, it is mani- 

 festly an error to recommend for nickel deposition a 

 solution of 8 pounds of nickel ammonium sulphate 

 per gallon (p. 220). Some of the recent develop- 

 ments in the practice of electroplating might have 

 been given more attention, such as electrolytic 

 methods of cleaning which of late years seem to have 

 corne into favour ; and the important uses of the sand 

 blast are still, as in former editions, almost ignored. 

 It is, however, impossible to deal adequately within 

 the limits of a volume of reasonable size, with all the 

 aspects of so wide a subiect. and the general excell- 

 NO. 2155, VOL. 85] 



ence of the treatise in its revised and enlarged form 

 elicits warm approval. 



The section devoted to electrolytic refining is much, 

 extended, and a very good summary on the smeltir^gl 

 of iron ores and the manufacture and refining of steel 

 by electrical means is a new feature in this edition. 

 There 'are a considerable number of useful tables given 

 as addenda, and chapter xx. consists of a convenient 

 glossary of substances commonly employed in electro- 

 metallurgy, with their more important properties, but^ 

 the melting points of the metals might have been 

 revised in the light of the great amount of laborious, 

 and excellent recent work done on these, such a 

 standard temperature as silver 961° C. being given 

 as 1740° F. (949° C), and the ancient myth of anti- 

 mony at 800° F. (427° C.) instead of 631° C. 



The book must, however, be considered as a 

 standard one on the subject, essential alike to students 

 and practical electrometallurgists. 



A. McWlLLIAM. 



Diptera Danica. Genera and Species of Flies 



hitherto found in Denmark. By W. Lundbeck. 



Part iii., Empididae. Pp. 329. (Copenhagen ; 



G. E. C. Gad; London : W. Wesley and Son, 1910.] 



Price 136-. 6d. net. 

 The family treated in the present instalment of the 

 "Diptera Danica" is one of considerable extent, 

 numbering 675 palasoarctic and 440 North American 

 species, eleven being recorded as common to both- 

 regions. The number of sjaecies described in the 

 present volume is 164 (Mr. E. E. Austin estimates 

 the number of British species as approximately 215), 

 divided into five subfamilies and twenty-seven genera. 

 The larvae live in damp ground, under leaves, or irr 

 mud, or in decaying wood, and are believed to be 

 carnivorous, like the perfect insects, the habits of 

 which are very curious, as recorded on pp. Sj^ and 84. 

 Sometimes the male catches an insect and presents it 

 to the female, who sucks it during their union, and 

 then drops it ; and in other cases the male presents the 

 female with a small dead fly enveloped in a kind of 

 balloon of froth. 



* The long and detailed descriptions of genera and 

 species appear to be very carefully written, and the 

 141 text-illustrations of antennae, wings, &'c., are ex- 

 cellent. The book deserves the patronage of all British 

 entomologists who are interested in Diptera, especially 

 as it is written and printed in English for their 

 benefit. Although there are now more entomologists- 

 working at Diptera at present, the order has been less- 

 studied in Britain than any other, and we have not 

 yet a sufficiency of works dealing with many large 

 and important groups comprised in it. 



Elementary Physiography. By Prof. R. D. Salisbury. 



Pp. xi + 359. (New York: H. Holfand Co., n.d.) 

 This work is a reduction and simplification of the 

 author's larger book for schools, which was reviewed 

 in Nature, vol. Ixxxii., p. 335. It is expressly in- 

 tended for schools that can give only half a year to the- 

 subject. The numerous illustrations retained will- 

 attract attention, and those dealing with types of 

 glaciers and their products are unusually varied and 

 effective. The Salton Sea (p. 96) has been utilised 

 as an example of delta-flooding, and the buckling of 

 tram-lines in San Francisco in 1906 is shown on p. 

 197. There is in all American work a desire to bring 

 the present activity of the earth home to the general 

 reader. The same spirit is seen in Prof Walther's 

 crusade on behalf of geology in Germany; and there 

 are signs that the next generation will not grow up 

 entirely ignorant of this strange rotating ball oiT 

 which we live. 



With the aid of maps and pictures from the British 



