590 



NATURE 



[January 27, 19 16 



ture. The experiment on p. 135, "to find the 

 temperature of a furnace," is misleading. A 

 piece of nickel is placed in the furnace and then 

 transferred to a calorimeter containing water, the 

 rise of temperature being noted. At 1000° C. 

 the specific heat of nickel differs very considerably 

 from the value at the ordinary temperature. On 

 p. 163 the authors cite the boiling of water in a 

 paper vessel as an effect similar to that obtaining 

 in a boiler plate. In a boiler plate of good con- 

 ducting material there is, of course, little differ- 

 ence of temperature between the two sides, but 

 paper is a bad conductor of heat, and the reason 

 the paper does not burn is due to an entirely 

 different cause. When water is boiled in a paper 

 vessel the escape of vapour through the paper is 

 considerable, and the flame is usually quite \ in. 

 from the paper. 



(3) Mr. Johnson's book is written for the am- 

 bitious artisan, and is based upon notes made by 

 the author during nine years' teaching experience 

 in evening vocational and technical schools in the 

 United States. For its perusal no further mathe- 

 matical knowledge is required than the elementary 

 rules of arithmetic, simple equations, and the 

 trigonometrical ratios of an angle. It includes 

 chapters on engineering measuring instruments, 

 calculations of areas and weights, pulleys and 

 belting, gearing, properties and strength of mate- 

 rials. Two chapters dealing with the elements 

 of statics are fully illustrated by practical ex- 

 amples from the workshop. The book is clearly 

 written and the diagrams are well executed. A 

 large number of numerical exercises are inter- 

 spersed in the text, but the workman bent on 

 self-improvement would find the book of con- 

 siderably greater value if the author had furnished 

 answers to these examples. 



(4) The collection of problems by Prof. Ryan 

 (upwards of one hundred) is intended to be used 

 with Morecroft's elementary text-book on "Con- 

 tinuous and Alternating Current Machinery," No 

 answers are provided. 



METALLURGY OF GOLD. 

 The Metallurgy of Gold. By Sir T. K. Rose. 

 Sixth edition. Pp. xix+6oi. (London: C. 

 Griffin and Co., Ltd., 1915.) Price 22s. 6d. 

 net. 



SIR THOMAS ROSE'S "Metallurgy of Gold " 

 has been recognised for the last twenty years 

 as the best general treatise on the metallurgy of the 

 metal ; the appearance of this new edition, which 

 by revision and expansion is practically a new 

 book, will hence be warmly welcomed by all 

 metallurgists. Since the last edition was pub- 

 NO. 2413, VOL. 96] 



lished in igo6 the changes which have been intro- 

 duced in the metallurgy of gold have been greater 

 than those in any other metal ; the need for a new 

 edition of the book was therefore imperative, and 

 this need has been admirably satisfied in the 

 present volume. 



As stated in the preface, "the most important 

 function which a book on metallurgy has to fulfil 

 is to help those who are taking part in attempts 

 to improve existing practice," and with that aim 

 in view the whole book has been thorougly re- 

 vised and much new matter added. The early 

 chapters, which have been rewritten and greatly 

 enlarged, now contain a remarkably full and 

 accurate account of the properties of gold, its 

 compounds and alloys, and throughout the volume 

 special attention is given to the principles under- 

 lying the various practical operations involved in 

 the extraction of the metal, and in the refining 

 and preparation of gold bullion for the market 

 and for minting. In this connection it will be 

 admitted by all that without a knowledge and 

 clear understanding of these properties and prin- 

 ciples, an acquaintance with mere practical de- 

 tails, however extensive, will not be sufficient to 

 enable the metallurgist to cope successfully with 

 the difficult problems which will confront him from 

 time to time in the practical operations of the 

 metallurgy of gold. 



The remarkable success which during recent 

 years has attended the introduction of the filtra- 

 tion of slime on the vacuum principle has led to 

 a complete change in the functions of the stamp 

 battery as a crushing machine ; the chapters deal- 

 ing with stamps, crushing, fine grinding, and 

 amalgamating machinery have hence been largely 

 rewritten and brought thoroughly up to date. 



But it is in the cyanide process that we find 

 the most conspicuous changes and advances, 

 hence the chapters devoted to it are for the most 

 part new. These chapters contain an authorita- 

 tive account of the various mechanical develop- 

 ments of the process of the principles involved 

 in working it, and of the latest and most approved 

 practice in modern cyanide works. Detailed de- 

 scriptions are given of the plant and appliances 

 in current practice for the treatment of sand, and 

 of the various agitators, vacuum filters, filter 

 presses, &c., employed in the treatment of slime. 

 Further, the reactions which take place in the 

 cyanide process, the conditions necessary for the 

 success of the various operations, and the best 

 means of carrying them out, from the crushing of 

 the ore to obtaining the gold as bullion, are all 

 given clearly and concisely. In chapter xvii. 

 modern practice is exemplified by the operations 

 at typical plants. These chapters contain, in fact. 



