March 30, 191 1] 



NATURE 



Ml 



COLLOID CHEMISTRY. 

 An Introduction to the Chemistry of the Colloids. A 

 Compendium of Colloidal Chemistry for Students, 

 Teachers, and Works Managers. By Dr. V. 

 Poschl. Translated from the second, enlarged, 

 German edition by Dr. H. H. Hodgson. Pp. 

 iv+114. (London: C. Griffin and Co., Ltd., 1910.) 

 Price 35. 6d. net. 



THIS short work is well described in its title as 

 a compendium of colloidal chemistry. Struck 

 bv the growing importance of this branch of chemical 

 science, the author has endeavoured to provide a brief 

 summary of the chief characteristic properties and 

 modes of preparation of colloids, as well as to indi- 

 cate some of the more important phenomena in the 

 production of which colloidal substances are con- 

 cerned. 



The chemical methods for the preparation of col- 

 loidal solutions of the hydroxides, sulphides, and 

 metals are described in some detail, together with 

 the properties of the resulting hydrosols, special at- 

 ti ntion being paid to gold and silver, the study of 

 which has done so much to advance our knowledge 

 of the colloids. The electrical methods, due to 

 Bredig, for the production of metallic hydrosols are 

 iilso well described, whereas the precipitation methods 

 by which colloidal solutions of sodium and barium 

 salts have been obtained are not mentioned. 



The character of the work is incompatible with 

 much discussion of the numerous knotty points which 

 must inevitably arise in any account of the various 

 theories of the colloidal state, but a clear description 

 of these theories is given, great stress being laid on 

 the positive evidence afforded by the ultramicroscope 

 that colloidal solutions are not homogeneous. Atten- 

 tion is also directed to the important fact that many 

 substances, a list of which is given, are known both 

 in the crystalline and colloidal forms, and that the 

 colloidal state is not necessarily a property only of 

 substances possessed of a large molecule and com- 

 plex chemical constitution, but may also be associated 

 with quite simple substances, the nature of solvent, 

 or, as it is better termed, the dispersion medium, 

 1m ing frequently the deciding factor. 



Perhaps too little stress is laid on the electro- 

 chemical relations of colloids, and the important sub- 

 ject of the mutual precipitation of colloids of oppo- 

 Mte electrical sign is dismissed in a single line. 



The concluding sections on the importance of col- 

 loidal chemistry in various branches of chemistry and 

 other sciences indicate very clearly how much 



--istance these are deriving from the realisation of 

 the fact that many familiar phenomena can only be 

 adequately understood in the light of our knowledge 

 of the colloids. 



On the whole, it may be said that the purpose 

 of the author in compiling this account of the colloids 



s been fully realised, and that the reader will gain 



j^ood idea of many of the points of interest con- 

 nected with this difficult and important subject. 



A. Harden. 

 MO. 2 161, \'OL. 86] 



UUR BOOK SHELt, 



An Introduction to the Study of Metallurgy. By Sir 



VV. C. Roberts-Austen, K.C.B., F.K.S. Sixth 



edition, revised and enlarged by F. VV. Harbord. 



Pp. XV + 478. (London: Charles Griffin and Co., 



Ltd., 1910.) Price i8a\ net. 

 The appearance of a new edition of Sir William 

 Roberts-Austen's "Introduction to the Study of 

 Metallurgy," which has been out of print for some 

 time, is to be heartily welcomed, as no other book 

 adequately fills its place in metallurgical literature. 

 Since its first publication there have been vast advances 

 in pyrometry, metallography, and in metallurgical 

 processes, advances which were only partially dealt 

 with in succeeding editions. In this the sixth edition 

 special attention has been given to the results of 

 recent research and metallurgical progress ; the chapter 

 on pyrometry has been rewritten, a new chapter on 

 metallography has been prepared, and in the chapter 

 on furnaces, descriptions and illustrations of typical 

 modern furnaces and appliances have been introduced 

 to replace those which are no longer in general use. 

 This chapter also contains an extremely useful account 

 of the construction, modes of working, and uses of 

 the three chief types of electric smelting furnaces. 



A valuable addition, the thermal treatment of certain 

 indulptrial alloys, has been made to chapter iv., which 

 in previous editions was confined almost entirely to 

 the thermal treatment of steel. 



The book is intended to give a systematic course 

 of study in the fundamental principles on which 

 metallurgical processes are based, and the success 

 of their various operations depend ; and for this it is 

 admirably adapted. It will be conceded by all that 

 without this knowledge the ditTiculties and irregulari- 

 ties which arise in metallurgical practice can be, if 

 at all, but imperfectly contended with. 



The information which is given on the subjects dealt 

 with, although necessarily brief in some cases, is set 

 forth with remarkable clearness, and is thoroughly 

 trustworthy and up to date. 



The new edition is an excellent piece of work, and 

 Mr. Harbord deserves the congratulations of metal- 

 lurgists for having brought this valuable text-book 

 into touch with the times. It is indispensable not 

 only to students, but to all who are engaged in 

 practical metallurgical work. W. G. 



Untersuchungcn ilbcr die Zoogeographie der Karpathen. 

 (Unter besondorer Beriicksichtigung der Coleop- 

 teren.) By Karl Holdhaus and F. Deubel. Pp. vi4- 

 202, and map. (Jena : Gustav Fischer, 19 10.) Price 

 8 marks. 

 In this important and carefully written work Prof. 

 Holdhaus analyses chiefly the Coleoptera of the Car- 

 pathians, with special reference to the influence of the 

 Glacial period on the Alpine fauna of Europe. We 

 may perhaps quote a few words from his introduction 

 to make his starting point clear, though possibly 

 the case is a little overstated, in view of the circum- 

 polar fauna and flora : — " During the Glacial period 

 all life was annihilated in northern Europe. The 

 animals at present inhabiting north Europe are post- 

 Glacial immigrants. The remarkable impoverishment 

 and monotony of the northern fauna — especially the 

 absence of a typical mountain fauna in Fenno-Scandia 

 — seems inexplicable except from this point of view. 

 In central and southern Europe the influence of the 

 Glacial period is chiefly visible m the mountain fauna." 

 Prof. Holdhaus commences by discussing the geo- 

 logical history of the Carpathians, and their climate 

 and vegetation. Then he proceeds to discuss the dis- 

 tribution of the Coleoptera of the Carpathians, and 

 the districts which they inhabit, the age and origin 

 of this fauna, and how far it has been influenced by 



