Seimemhkr 8, 1910] 



NATURE 



295 



COLULK CHEMISTRY. 



A Manual of Dyeing : for the Use of Practical Dyers, 

 Manufacturers, Students, and all Interested in the 

 Art of Dyeing. By Prof. E. Knecht, C. Rawson, 

 and Dr. R. Loewenthal. Second edition. Vol. i., 

 pp. xii + 371. \'ol. ii., pp. 372-902. (London : 

 I.". Griffin and Co., Ltd., 1910.J Price 45^., two 

 • ols. 



I'^HE first edition of this work was reviewed in 

 Nait're on June 22, 1893, and in the seventeen 

 vears which have elapsed since its publication, such 

 rapid developments have taken place in colour chem- 

 istry that certain sections of the book have for some 

 time been out of date, and the whole work has for 

 several years been out of print. The issue of the 

 present edition has, therefore, involved a very com- 

 plete and laborious revision, and this no doubt 

 accounts for the somewhat protracted delay in its 

 issue. 



This raises the question whether, for the sake both 

 of authors and purchasers, some scheme could not be 

 devised for arranging and binding a book of this type 

 in such a manner that sections could be re-written and 

 issued separately. 



The general scheme of the book has not been 

 materially altered, but vol. iii. of the first edition, 

 which consisted of illustrative dyed patterns, has not 

 been reproduced, and in this the authors have been 

 well advised. 



The section dealing with the theory of dyeing pro- 

 cesses has been extended to three times its original 

 length, but any general agreement with regard to the 

 theory of dyeing does not at present appear possible, 

 nor have theoretical considerations in the past been of 

 much service in connection with the practical applica- 

 tion of colouring matters. It is to be hoped that 

 further investigation will lead to such a unification of 

 ideas that theory may fulfil its proper function of a 

 sign-post for those seeking new fields of practical 

 application. 



In the section dealing w'ith textile fibres, five excel- 

 lent plates replace the older diagrammatic illustrations. 

 While the ordinarv fibres are adequatelv described, the 

 treatment of artificial silk seems hardly to have re- 

 ceived that attention to which its present great com- 

 mercial importance entitles it. There is, for instance, 

 no reference to Thiele silk, one of the chief products 

 now used. 



Part vi. comprises a description of the natural colour- 

 ing matters, and in this section it has been found 

 possible to condense the matter originally published, 

 this being in agreement with the diminished import- 

 ance of these dye-stuffs from the practical point of 

 view. The recent work of A. G. Perkin, v. Kosta- 

 necki, Schmidt, and others, on the constitution of the 

 colouring matters of the natural dye-stuffs, is duly 

 referred to. 



The most extensive section of the book is, of course, 

 that dealing with the artificial dye-stuffs, and this has 

 required the greatest amount of revision. Certain 

 entirely new groups of dyes, such as the artificial vat 

 colours, have been introduced since the publication of 

 NO. 2132, VOL. 84] 



the first edition, and other groups, such as the sulphide 

 dyes, have been greatly enlarged. Some mention of 

 Tyrian purple might well have been included in view 

 of P. Friedlaender's discovery that it is a dibrom- 

 indigotin. 



A section of the work to which great importance 

 has always been attached is that dealing with the 

 analysis and valuation of materials used in dyeing, 

 and this has received a very thorough revision. 



The book in its new edition will again take its place 

 as one of the most important works published on 

 colouring matters and their application. 



OUR BOOK SHELF. 

 La Met alio graphie Microscopique. By Louis Rdvillon. 



Pp. 176. (Paris : Gauthier-Villars, n.d.) Price 3 



francs. 

 This is another volume of the small Aide-Memoire 

 series bv the author of the work on " .Special Steels," 

 which was reviewed some time ago. Considering the 

 size and price of the book, a good account of the 

 subject is given, though, in common with many other 

 enthusiasts, tlie author is inclined to claim too much 

 for his subject, p. 7, " et de r^soudre tous les 

 problemes . . .," and in describing the preparation of 

 the polished face of the section for examination, is too 

 severe in his conditions, namely, "perfectly polished 

 so that there remains no scratch visible at the highest 

 power of the microscope." Much time has been 

 wasted in the past in striving after this ideal. It is 

 not necessary, unless when looking for the finest 

 cracks, and, combined with a somewhat elaborate 

 series of precautions, is apt to discourage the reader 

 from beginning practical work. Advice such as that 

 given on pp. 69 and 70 has always been impressed on 

 iaeginners bv the writer, namely, that the section is 

 prepared for observation and study, not merely for 

 photographing, and that the polished section should 

 alwavs be examined carefully before etching in any 

 way, as then small holes, oxides, scoriae, and sulphides 

 are generallv much more easily seen against the 

 polished metallic surface than after etching. 



With manv of the opinions expressed one cannot 

 agree. The Martensitic interlacing needles do not 

 represent the structure of properly hardened carbon 

 steels, and manv practical points might also be con- 

 troverted, but tlie work as a whole gives a very fair 

 introduction to a study of the subject from the point 

 of view of a portion of the French school. Osmondite 

 is given, although M. Osmond has specifically repu- 

 diated it in Revue de MHallurgie. Separate chapters 

 are devoted to special steels, the alloys of copper, 

 other industrial alloys, and the final chapter to the 

 interesting " Macrographie." A. McWilliam. 



Die Kraftmaschinen. By C. .Schutze. Pp. vi + 23,. 



(Leipzig: Quelle and Meyer, 1909.) Price 1.80 



marks. 

 This little volume is devoted to a non-mathematical 

 description of the various types of motors now em- 

 ployed for pow-er purposes, and of the more important 

 details of each class; windmills, waterwheels, and tur- 

 bines, steam, gas, and petrol engines, and dynamos 

 and electric motors are all in turn discussed and 

 described. The text is illustrated by a large number 

 of figures, mostly line illustrations, and, as all minute 

 details are omitted, these illustrations will be easily 

 understood and followed by the non-technical reader. 

 The whole volume is, in fact, intended for those who 

 are not experts in this branch of engineering. It will 

 appeal, however, to manv who use motors for business 



