112 



NATURE 



[October i, 19 14 



the hen-pheasant is sitting, the miscellaneous diet, 

 the assumption of male plumage by hens, the 

 crossing with capercailzie, blackgame, guinea- 

 fowl, and poultry. We are not forgetting that 

 this is not the first book on the pheasant, but it 

 is written with freshness and first-hand knowledge, 

 and should enjoy a deserved popularity. 



(3) We are much behind the times in Britain as 

 regards aviculture, and it is to be hoped that Mr. 

 John H. Robinson's very competent book will 

 serve as a stimulus. It has been computed that 

 the annual production of poultry in the United 

 States approaches the value of a thousand million 

 dollars, and Mr. Robinson shows that there is 

 pleasure as well as profit in the business. We 

 do not think that anyone can read his book with- 

 out wishing more power to the elbow of those 

 who have been active in recent years in increas- 

 ing and improving poultry-keeping in this 

 country. It should be noted that Mr. Robinson's 

 book is actually meant for schools, and that he 

 defends this on educational as well as on utili- 

 tarian grounds. His enthusiasm is not damped 

 by any thought of the danger, probably in great 

 part a bogey, of tethering school-children too 

 early to the practical problems of life. A second 

 book of a purely technical character is, we under- 

 stand, being prepared ; the object of this one is : 



"To tell in plain language the things that 

 everyone ought to know about poultry, pigeons, 

 and cage birds ; to teach fundamental facts in 

 such a way that they will be fixed in the mind ; 

 to excite interest in the subject where none 

 existed ; and to direct enthusiasm along right 

 lines." 



Mr. Robinson is not afraid of what his fellow- 

 countrymen sometimes call "hen-fever." 



The book deals in a robust practical way with 

 fowls, ducks, geese, turkeys, guinea-fowls, pea- 

 fowls, pheasants, swans, ostriches, pigeons, and 

 canaries and it seems to us to fulfil its purpose. 

 Our only suggestion is that, before a second 

 edition is printed, the author should get some 

 zoological friend to read over the general intro- 

 duction, which is not without blemish. If avi- 

 culture is to be a school-subject, its presentation 

 should be scrupulously accurate. Therefore, some 

 changes should be made in statements such as 

 the following : " Many insects and one species of 

 mammal (the bat) fly." "Man learned melody 

 from the song birds." "These yolks are not 

 germs, but as they grow the germ forms on one 

 side of each yolk, where it appears as a small 

 white spot." These are merely examples of 

 different kinds of statements which admit of im- 

 provement. On page 35 it is indicated that the 

 theory of the origin of domestic fowl from the 

 Indian jungle fowl is no longer tenable, but we 

 NO- 2^AA.. VOT.. Qa1 



would refer the author to a v,rell-known American 

 ornithologist, Mr. C. W. Beebe, who wrote in 

 April of this year : " I can find no reason to attri- 

 bute the ancestry of all varieties of our domestic 

 fowls to other than the red jungle fowl of India, 

 Gallus Gallus (Linnaeus)." We have not ob- 

 served any reference to Mendelism in Mr. 

 Robinson's book, but we suppose the omission 

 must be deliberate. If so, one would like to 

 know why. 



SILICA AND SILICATES 

 La Silice et les Silicates. By Henry Le Chatelier. 

 Pp- 574- (Paris : A. Hermann et Fils, 1914.) 

 Price 15 francs. 



SILICA, as is well known, constitutes a large 

 proportion of the earth's crust, and in some 

 form or other plays a very important part in 

 commerce and industry. Silica and silicates are 

 largely used as material for building purposes, 

 for pottery, glass, cement, fluxes, etc. Their full 

 importance is perhaps not brought out in the 

 ordinary text-books; comparatively little is said 

 about them in most books on chemistry and, on 

 the other hand, while in treatises on mineralogy 

 a considerable proportion of the pages are de- 

 voted to this large mineral group in their 

 scientific aspect, their practical applications are 

 almost wholly ignored. Prof. Le Chatelier's 

 work is therefore very welcome, especially since 

 it is from the pen of one who has himself done 

 so much to extend our knowledge of the physical 

 properties of the products of these materials. 



After a short introduction, in which he 

 epitomises the scope of the book, the author 

 enters into a full description of the characters of 

 the anhydrous and hydrous forms of silica, 

 typified respectively by quartz and chalcedony, 

 and by opal; the rare tridymite and cristobalite 

 are, however, also discussed. Apart from 

 jewelry, quartz is invaluable in saccharimetry 

 and microscopy, and in recent years an extremely 

 important use has been discovered for it in its 

 amorphous form. The excellence of quartz 

 fibres for torsional purposes was pointed out by 

 Boys a quarter of a century ago, and his in- 

 genious method of preparing them has never been 

 improved upon. For vessels likely to be sub- 

 jected to rapid and considerable changes of tem- 

 perature amorphous quartz far surpasses glass, 

 and finds extensive use at the present day. Next 

 in a series of five chapters the properties and 

 peculiarities of the principal different varieties of 

 glass are fully discussed. 



The various silicates are described in the fol- 

 lowing series of chapters, but the characters of 



