June 29, 1911] 



NATURE 



581 



him on the arid shores, strewn with striated boulders, 

 of Tempel Bay or Cora Island. 



The transport of boulders and striation of rock- 

 floors by ice are, of course, fully admitted, and we 

 have interesting references to Playfair, Perraudin, and 

 de Charpentier. A short account of the origins of 

 sedimentary rocks follows, in which, by a slip, fresh- 

 water shell-limestones become included under "roches 

 argileuses." This part of the book may be regarded 

 as consisting of somewhat scattered notes, all of which 

 have an interest for the professed geologist, but which 

 do not systematically express the growth of geological 

 opinion. 



The absence of an index is astonishing. Perhaps 

 the publisher quailed before the proper names, which 

 are very imperfectly corrected in the text. We have 

 Leibniz, Hitchkock and Hitchcok, Mayer-Aymar, 

 Uscher, Revenier, Spalanzani, Moris Davis, d'Aubuis- 

 son de Voisin, and Deshays. One or two dates seem 

 erroneous by about a century. G. A. J. C. 



LEAD SMELTING. 

 The Metallurgy of Lead. By H. F. Collins. Edited by 

 Sir W. C. Roberts-Austin, K.C.B., F.R.S, Second 

 edition, thoroughly revised and enlarged. Pp. xx + 

 538. (London : C. Griffin and Co., Ltd., 1910.) 

 Price 215. net. 



AA/^ welcome a revised and enlarged edition of 

 * V this useful work, as the progress of metal- 

 lurcrv is now so rapid and great improvements have 

 been made in smelting during the last decade. A too 

 brief reference has been made to the physical proper- 

 ties of lead and that of its alloys, and much recent 

 work has been overlooked, probably due to the aim 

 of the author in making the work chiefly a compen- 

 dium of information on lead smelting, which is here 

 brought well up to date. Ore roasting has received 

 the attention it deserves, and we are glad to find that 

 pot roasting is clearly described, and the chemical 

 reactions occurring in this novel process fully dis- 

 cussed, since a correct knowledge of the chemical 

 chanp-es that occur in any process often leads to ad- 

 vancement and discoveries. Useful data are given 

 as to costs in the various modifications developed from 

 the Huntingdon-Heberlein process. 



The most suitable fuel for a given ore is here rightly 

 considered, as well as the proper amount to be used 

 in each case. But the twyer ratio and twyer efficiency 

 are also of great significance, and it is a pity more 

 attention has not been given to the pressure and 

 volume of air supplied to each furnace. 



The principles of blast-furnace lead smelting are 

 clearly expressed, as the method of dealing with each 

 constituent, according to its quantity, is essential for 

 economic working. It is also equally important that 

 the proper flux should be applied in order to produce 

 the most suitable slag and to obtain the maximum 

 quantity of metal. This is dealt with in a plain and 

 lucid manner. A comprehensive description of modern 

 furnaces with plentiful illustrations is a good feature 

 in this edition, the parts being described in consider- 

 able detail. The important subject of water-jackets 

 receives due attention as more refractory ores have 

 NO. 2174, VOL. 86] 



now to be dealt with, necessitating greater height of 

 jacket than formerly. It is shown that with increase 

 of size of furnaces and amount of output larger fore- 

 hearths are required and greater facilities for separat- 

 ing matter and slag. The treatment and disposal of 

 slag are also given due prominence. Formerly the pro- 

 duction of matte was considered a necessary evil, but 

 it is now esteemed a desirable thing, since the lead is 

 better reduced and the slag more free from lead and 

 silver. 



The various products of lead smelting are amply 

 described, as well as the methods adopted for dealing 

 with them at different works. 



In chapter xi. examples of lead smelting in the 

 chief European and American works form the subject 

 of narration, and the following chapter deals with 

 costs and losses. 



As all lead ores carry silver and sometimes gold, it 

 often becomes more profitable to work for their ex- 

 traction than that of the lead itself. The author 

 devotes about 100 pages to a consideration of this 

 important subject. A valuable part of this section is 

 the description of the methods of separating gold from 

 zinc crusts. 



In chapter xix. works assaying and analytical 

 methods are dealt with. 



In the following chapter the difficult subject of 

 treatment of zinc-lead sulphides is considered, and 

 various methods of separation discussed. 



The last chapter deals with flotation processes, 

 which have in recent years assumed great importance. 



We consider this work a valuable contribution to 

 the metallurgy of lead, in which so much new matter 

 has been introduced, and it can be confidently recom- 

 mended as a trustworthy guide to anyone who is 

 interested in the subject. 



THE TRISECTION OF .iN ANGLE. 

 The Trisection of the Angle by Plane Geometry: VefU 

 fied by Trigonometry with Concrete Examples. By 

 Dr. J. Whiteford. Pp. 169. (Greenock : J. 

 McKelire and Sons, Ltd. ; Edinburgh and Glasgow : 

 J. Menzies and Co., Ltd.; Cambridge: l3owes and 

 Bowes, 191 1.) 



THE Paralogistcs pseudomaihcmatictis has become 

 so rare, or possibly so shy, that it is a real 

 pleasure to find that the species is not extinct. Alack ! 

 that De Morgan is not with us, to do justice to this 

 latest attempt at solving one of the three famous 

 problems that have been proved to be beyond the 

 power of Euclidean constructions. The curious thing 

 is that the author, in his introduction, gives two long 

 quotations from De Morgan, in which he states the 

 conditions of the problem with the utmost precision, 

 except that he does not explicitly say that the tri- 

 section must be performed by a finite number of opera- 

 tions. It is here that Dr. Whiteford has come to 

 grief, for his method is nothing more or less than 

 successive approximations, each of which involves a 

 Euclidean construction. It is only fair to add that 

 the author is no vulgar paradoxer, and that his 

 method, as an approximation, is sound, and leads to 

 accurate values with a comparatively small number of 



