NATURE 



425 



THURSDAY, MARCH 6, 1884 



RECENT TEXT-BOOKS ON TECHNOLOG\ 



1. Steel and Iron. By William Henry Greenwood. 

 (London : Cassell and Co., 1884.) 



2. Bleaching, Dyeing, and Calico Printing. Edited by 

 John Gardner. (London : Churchills, 1S84.) 



3. The Art of Soap- Making. By Alex. Watt. (London: 

 Crosby Lockwood and Co., 1884.) 



A LTHOUGH the comprehensive system of techno- 

 logical examinations established under the direction 

 of the City and Guilds of London Institute has been at 

 work only a comparatively short time, it has already 

 called into existence a considerable number of manuals 

 and text-books designed to meet the special requirements 

 of teachers and students in connection with those exami- 

 nations. No doubt excellent works in certain branches 

 of technology already exist, but many of these are scarcely 

 suited to the purpose of the teacher, and most of them 

 are in price beyond the means of the class which the 

 Institute seeks to benefit. The action of many of our 

 leading publishing houses in thus vying with each other 

 in the production of series of low-priced handbooks of 

 technology to meet a demand primarily created by the 

 policy of the Institute is calculated not only to serve the 

 interests of those preparing for examinations but also to 

 react beneficently upon the general intelligence of our 

 workmen. Numbers of these smaller works find their way 

 into the hands of the better class of our mechanics, foremen, 

 and apprentices, to whom the larger and more elaborate 

 works, even when present in our free libraries, are as sealed 

 books. On the whole, it may be said that the handbooks 

 which have already appeared have been prepared with a 

 rational appreciation of the needs of intelligent practical 

 men. The majority of them are written or compiled by 

 specialists, or by men who are well acquainted with the 

 industries to which their works relate, and their descrip- 

 tions and statements are made with the authority and 

 discrimination which result from a practical knowledge of 

 the manufactures of which they treat. The first and third 

 of the works before us are excellent illustrations of this 

 fact. In Mr. Greenwood's manual we have not only a 

 comprehensive account of the present condition of our 

 iron and steel manufacture, full of sound, practical infor- 

 mation, but a very clear and accurate exposition of the 

 scientific principles upon which the manufacture depends. 

 The information is fully up to date ; the illustrations are 

 not mere pictures, but diagrams based upon original draw- 

 ings, the majority of which have been reduced from scale 

 plans of existing plant, and so arranged as to be readily 

 understood by those who have only a slight experience of 

 mechanical drawings. The chemical portion of the work 

 makes no pretensions to be exhaustive, but it is accurate 

 and sufficiently full. On p. 63, however, we notice that 

 the composition of spiegeleisen is represented by the 

 formula FeMn.,C, probably a misprint for (FeMn)4C, 

 although the evidence in support of the existence of any 

 such definite carbide is very weak. A characteristic 

 feature of the work is seen in the prominence given to 

 Vol. XXIX.— No. 749 



such Continental processes as may possibly react upon 

 English methods, as for example the Perrot revolving 

 puddling furnace, and the various reheating furnaces of 

 Bicheroux, Casson, and Ponsard. The chapters on steel 

 are remarkably concise and complete. The author meets 

 the well-known difficulty of definition by assuming that 

 any compound of iron and carbon which is delivered from 

 a vessel in a state of fusion and at once cast into malle- 

 able ingots may be considered as steel. This definition 

 is perhaps not very rational or precise ; it seeks to exclude 

 cast iron on the ground of its immalleability, and wrought 

 iron from the circumstance that in practice it is never 

 obtained wholly fu5ed ; however, it is at least more accu- 

 rate than that based upon the quality of hardening and 

 tempering, which the so-called mild steels do not possess 

 to any sensible extent. 



The volume on " Bleaching, Dyeing, and Calico Print- 

 ing " is a production of a very different character. It has 

 not the slightest claim to originality, but is mainly a com- 

 pilation, of some 200 pages, from the standard works of 

 Crookes, Stenhouse, and Groves and Ure, and consists 

 very largely of receipts and formula:. The chapter on 

 bleaching is fairly well done, especially the portion relat- 

 ing to linen bleaching ; and the section on mordants is 

 good so far as it goes. What there is of chemistry in the 

 book is generally accurate, but the author would in nowise 

 have diminished the air of practicality about his work if 

 he had removed or replaced some of the barbarisms in 

 chemical nomenclature aflected by dyers. It is quite 

 possible to be precise without being pedantic. The book 

 is poorly illustrated and somewhat loosely put together. 



Mr. Watt's book on " Soap-Making" is a thoroughly 

 practical treatise on an art which has almost no literature 

 in our language. The author is the son of the late Mr. 

 Chas. Watt, the inventor of the well-known process of 

 bleaching palm-oil for soap-makers, and he has been con- 

 nected with that industry for many years. Soap seems 

 to have been made in England only since the middle of 

 the seventeenth century, but the manufacture made very 

 little progress until the invention of the Leblanc pro- 

 cess for converting common salt into carbonate of 

 soda. The art received its second great impetus from 

 the labours of the venerable Chevreul in the early part of 

 this century, who, with Liebig, elucidated the theoretical 

 principles upon which the manufacture depends. Mr. 

 Watt's book shows what influence these researches have 

 had upon the development of the art, not only directly, 

 but as demonstrating to the soap manufacturer the im- 

 portance of a knowledge of chemistry in its applications 

 to his processes. The general theory of saponification is 

 first explained, and is followed by a chapter on the 

 arrangement of a soap factory and a description of the 

 materials used in soap-making. The various methods of 

 making hard soaps and cheapened soaps are then fully 

 described, both by the old processes and by those of 

 Hawes and Bennett and Gibbs, Rogers, and Berghart. 

 The processes for manufacturing potash soaps and soaps 

 for printed goods and silks are next explained, and there 

 are special chapters on toilet and medicated soaps, alkali- 

 metry and the methods of soap-analysis, and on the 

 recovery of glycerine from spent lyes. We congratulate 

 Mr. Watt on the success of his endeavour to fill a void in 

 English technical literature. T. E. Thorpe 



