518 



SCIENCE 



[N. S. Vol. XXXVI. No. 929 



inal sources. The book is brought well down 

 to date, and is conspicuous by the absence of 

 descriptions of antiquated methods which have 

 only a historical interest. Covering, as it 

 does with the other volumes, the whole field 

 of the analytical chemistry of technical prod- 

 ucts, the book is indispensable to the library 

 of every analytical chemist. 



The other book under review has since the 

 publication of its first edition been recognized 

 as the standard work on the manufacture of 

 sulfuric acid and alkali. This third volume 

 was in earlier editions the concluding vol- 

 ume, but, so great has been the development 

 of electrolytic methods of manufacture in re- 

 cent years, it has been found necessary to add 

 a fourth volume, which is shortly to appear, 

 and which is to include the electrolytic manu- 

 facture of alkali and chlorin. This will be 

 prepared by Professor Askenasy and Pro- 

 fessor Haber, recognized authorities on the 

 subject. The work of Dr. Lunge is concluded 

 with this third volume, which is devoted to 

 the ammonia-soda process, processes for the 

 manufacture of soda other than the LeBlanc 

 and the ammonia-soda, and to the manufac- 

 ture and utilization of chlorin. This last sec- 

 tion includes bleaching powder and other 

 bleaching liquors and compounds, and the 

 chlorates. 



It is rather striking that in as important 

 industry as the manufacture of soda, the 

 methods all but exclusively used throughout 

 the nineteenth century were the LeBlanc, first 

 put in operation before the century opened, 

 and the ammonia process, suggested at least 

 early in the century. Further, while the me- 

 chanical details, of course, were greatly im- 

 proved, there was practically no change in the 

 chemical principles involved. Curiously the 

 first suggestion of the ammonia process seems 

 to have come from Fresnel in 1811, but " the 

 invention soon sank into oblivion, and Fresnel 

 himself, whose thoughts were later fully 

 occupied by his magnificent reforms in the do- 

 main of optics, did not give any more time to 

 it." John Thom, a chemist in the factory of 

 Turnbull and Ramsay in Scotland, actually 

 worked the process, including the ammonia 



recovery in 1836, but it was later abandoned, 

 though his other practise of utilizing the am- 

 monia residues as manure won for Thom the 

 merit of founding the industry of artificial 

 fertilizers. In 1838 the first patents on the 

 process were taken out by Dyar and Hemming, 

 and various manufacturers experimented 

 with it, but in the hands of none did it prove 

 a commercial competitor with the LeBlanc. 

 The mechanical difiiculties were great, and 

 then, owing to the recovery of the chlorin 

 by-products, the LeBlanc process has always 

 been able to compete with the ammonia 

 method. It was not till 1861 that the Belgian 

 Solvay began independently the development 

 of the ammonia process, now perhaps more 

 commonly known as the Solvay process, and 

 soon placed it on a commercial basis. Since 

 that time the output has steadily increased, 

 passing that of the LeBlanc process about 

 1888, and from that time the production by 

 the latter process has constantly declined. In 

 this country the LeBlanc process has never 

 been worked, while the ammonia process has 

 had considerable development. Both these 

 processes are now threatened, especially in 

 this country, by the recent rapid development 

 of electrolytic processes, which will in the 

 near future probably drive the LeBlanc proc- 

 ess to the wall. 



The hundred or so pages of the book de- 

 voted to the description of " other processes " 

 is interesting reading, but somewhat painful, 

 representing as it does so many futile hopes. 

 Not less than a hundred diiferent methods, 

 most of them represented by sometimes sev- 

 eral patents, are referred to, and not one of 

 them (excepting the cryolite process) is of 

 appreciable commercial value at present. The 

 same may be said of most of the suggested 

 processes of chlorin manufacture, for it is 

 hardly a rash prediction that these will all 

 soon give way to the electrolytic manufacture. 

 In the statistical tables at the end of the book 

 we note that in 1904 half of the chlorin prod- 

 ucts the world over were from electrolytic 

 chlorin, and that only in Great Britain and 

 France was LeBlanc chlorin predominant. 

 We also note that in 1895 the United States 



