I2 4 



NA TURE 



[December 7, 1905 



graphs taken by the author himself. In a country 

 of the size and extent of America, with climates 

 ranging from the arctic to the tropical, and with 

 large tracts of more or less untrodden wastes, the 

 bird-lover and photographer has, of course, vastly 

 greater opportunities (especially among the larger 

 species, to which the author has confined his atten- 

 tion) than his brother in our own islands, and it 

 must be confessed that these opportunities have not 

 been neglected, for a more delightful book, both as 

 regards text and illustrations, it would be difficult to 

 produce. 



The breeding colonies of brown pelicans of New 

 England must form a really marvellous sight. On 

 the occasion of the first visit of the author and his 

 partv, the boat was run ashore without alarming the 

 birds. " Then," writes the narrator, " we stood up 

 and shouted, but hardly a bird rose. There they sat 

 upon their nests, hundreds and thousands of them, 

 many within forty or fifty feet, solemnly gazing at 

 us. It was not until we sprang out upon the shore 

 that there was any considerable flight, and even then 

 we noticed that it occurred only within a radius of 

 fifty or sixty feet, the rest of the colony remaining 

 on their nests apparently in perfect unconcern." 

 Time after time the colony has been raided by feather 

 and egg hunters, but it is satisfactory to learn that 

 Pelican Island has recently been made by President 

 Roosevelt a Government reserve for wild birds. 



Not less interesting is the author's account of the 

 colonies of white ibises and Louisiana herons in the 

 Cape Sable wilderness, this being followed by a 

 fascinating description, with equally fascinating 

 photographs, of the colonies of sooty terns and 

 noddies on " Lonely Bird Key," in the Dry Tortugas 

 group, far out in the Gulf of Mexico. But if we were 

 to cite even a tenth of the passages to which we 

 should like to refer, editorial limits would be far 

 exceeded, and in bringing this brief notice of an 

 admirable bird-book to a close we cannot do better 

 than advise our readers to get copies for themselves. 



Instruction in Photography. By Sir \V. de W. 

 Abnev. Eleventh edition, revised. Pp. 676. (Lon- 

 don : Iliffe and Sons, Ltd., 1905.) Price ~s. bd. 

 net. 

 This work, which for many years has held the premier 

 position among English text-books of photography, 

 is to a peculiar extent the record of the author's own 

 experiments and investigations, and in the new edition 

 much new matter on the subject of colour photo- 

 graphy has been added, the product of the attention 

 which Sir W. de W. Abney has devoted to that 

 branch of photography for some years. In other 

 sections of the book it may be noted that the descrip- 

 tions of lenses are brought up to date, while the 

 chapter on sensitometry includes a description of Mr. 

 Chapman Jones's plate tester. An entirely new- 

 chapter has been added to the book entitled " The 

 Failure of a Photographic Law," and including the 

 well known experiments made by the author upon 

 the effect of intermittent exposures and upon the 

 failure of the reciprocity law. Here also will be found 

 an interesting discussion of the effect of temperature 

 upon the sensitiveness of plates, while the last part 

 of the chapter is devoted to an account of the author's 

 researches upon the effect of different monochromatic 

 lights upon a plate. The book has been entirely 

 reset, larger type being employed throughout and 

 the printing generally improved. No alteration has 

 been made in the theoretical views set forth, and the 

 silver sub-bromide theory of the latent image is 

 adopted in its entirety. C. E. K. M. 



NO. 1884, VOL. J 3] 



La Bobine d' Induction, By H. Armagnat. Pp. 228. 



(Paris : Gauthier-Villars, 1905.) Price 5 francs. 

 In this book a very interesting account is given of 

 the induction coil in its theoretical and practical 

 aspects. The electromagnetic problems involved are 

 clearly stated, and the various factors which stand in 

 the way of a complete mathematical theory are con- 

 sidered in some detail. The effects of sparking at 

 the interruptor, the parts played by the iron core, by 

 the secondary capacity, &c, are carefully examined 

 and methods of experimental investigation are illus- 

 trated. The differences between mechanical and elec- 

 trolytic interrupters are discussed, and the more 

 purely theoretical part of the book concludes with a 

 chapter on the power and output of a coil and of the 

 factors upon which these depend. The methods of 

 measuring the electromagnetic constants of a coil are 

 indicated, as are the most common sources of break- 

 down, how they may be detected, and how in some 

 r.iscs remedied. 



In the description of the practical construction of 

 coils which follows, the different methods of winding, 

 insulation, &c, are described in detail, and the relative 

 dimensions of the various parts of coils of standard 

 makes are given. The particular features of different 

 types of interruptors, mechanical and electrolytic, upon 

 which efficient working depends are stated clearly 

 (although the action of the commonest mechanical 

 interruptor is not quite so simple as it is made to 

 appear, and might perhaps have been described in 

 greater detail in a book of this kind). 



The principles of the action of several special forms, 

 sim h as Tesla's, of induction apparatus used in prac- 

 tice are given in outline, and a final chapter is devoted 

 to a description of the various uses of induction coils. 

 The range of this chapter is perhaps indicated when 

 it is said that it includes the discussion of such ques- 

 tions as the ignition apparatus of explosion-engines 

 and the production of ozone. 



A very useful bibliography, in which the references 

 an- in most cases accompanied by short abstracts, 

 completes an excellent book. 



Handbook of Metallurgy. By Prof. Carl Schnabel. 



Translated by Prof. Henry Louis. Second Edition. 



Vol. i. Copper — Lead — Silver — Gold. Pp. xx + 



1123. (London: Macmillan and Co., Ltd., 1905.) 



Price 255. net. 

 This volume is a translation of the second German 

 edition which appeared in 1902. Prof. Schnabel has 

 found it necessary to increase the length of the book 

 considerably, the translation being 214 pages longer 

 than that of the first edition. A number of new fur- 

 naces and other appliances are described, and in par- 

 ticular the account of the extraction of copper by 

 electro-metallurgical methods has undergone great 

 expansion. The older metallurgical methods are pur- 

 posely dwelt on by the author, who gives as his reason 

 that a knowledge of the development of metallurgy 

 stimulates inventive genius. It is equally certain 

 that the inclusion of the descriptions of out-of-date 

 methods helps to make books bulky. 



The merits and defects of the book remain much 

 the same as in the first edition. It contains a mass 

 of detailed information as to the dimensions of appli- 

 ances in use at particular works, the analyses of 

 products, and the like, but the discussion of the 

 principles underlying the practice is generally less 

 thorough. This is as much as to say that the book is 

 "practical." Prof. Louis is to be congratulated on 

 the translation, which makes a valuable work avail- 

 able to British students. 



