December 9, 1915] 



NATURE 



393 



THE CHLORINE INDUSTRY. 

 Manuals of Chemical Technology : iv.. Chlorine 

 and Chlorine Products. By Dr. G. Martin. 

 Pp. viii+ioo. (London: Crosby Lockwood 

 and Son, 1915.) Price 75. 6d. net. 



IN the book before us, the fourth of a series 

 of manuals of chemical technology which 

 are being- published under the direction of Dr. 

 Geoffrey Martin, the editor gives a concise account 

 of the present condition of the chlorine industry, 

 and of the applications of this substance to the 

 manufacture of bleaching powder, hypochlorites, 

 chlorates, perchlorates, etc., and of its use as a 

 chlorinating agent ; with short sections on the 

 manufacture and industrial uses of bromine, 

 iodine, hydrochloric and hydrofluoric acids; and, 

 by way of appendix, a chapter of some half-dozen 

 pages, by Mr. G. W. Clough, on recent oxidising 

 agents — of no very direct connection with the 

 ttiain subject-matter of the book. 



It is scarcely to be expected, in a book of 

 100 octavo openly printed pages, with much 

 of the space occupied by illustrations, that 

 more than the very slightest and most superficial 

 treatment is possible, wholly incommensurable, it 

 must be admitted, with the enormous commercial 

 importance of the subject. At the same time, the 

 little work contains a considerable amount of in- 

 formation, and as an apergu of the contemporary 

 state of the relations of the halogens to chemical 

 industry, it is interesting, and not without value 

 to the student who desires only a general acquaint- 

 ance with the trend of recent developments in 

 chemical technology. For fuller information the 

 reader is referred to special or larger treatises, the 

 titles of which are given as headings to the several 

 chapters. Indeed, the bibliographies and patent 

 lists, as in the case of the other members of the 

 series, are among the most commendable features 

 of the book. It must be stated, however, that a 

 considerable number of these references are to 

 German sources, altogether inaccessible to the 

 ordinary reader, or even to the majority of those 

 specially interested in the subjects. 



During recent years a radical change has 

 come over the manufacture of chlorine, and in all 

 probability at least one of the processes which 

 have originated in this country, and which in its 

 day effected nothing less than a revolution in the 

 alkali trade, is doomed ultimately to extinction. 

 The Weldon process, which at its inception may 

 be said to have saved the position of the Leblanc 

 soda industry, at one time threatened by the rapid 

 lovelopment of the ammonia-soda process, has 

 now reached apparently its full extension, and 

 makes no further progress. On the other hand, the 

 competing process of Deacon and Hurter, thanks 

 NO. 2406, VOL. 96] 



to the mechanical improvements introduced by 

 Hasenclever and to the elaborate investigations of 

 Haber, Lunge and Marmier, Vogel von Falcken- 

 stein and others, on the thermodynamical problems 

 involved, and on the specific action of various 

 "contact agents," still holds its own, and is stated 

 to be even advancing, in spite of many technical 

 difficulties only to be overcome by skill and in- 

 telligent management. But it may be doubted 

 whether even this process will ultimately survive 

 the competition of electrolytic chlorine. 



The application of electrolytic methods to 

 chemical manufacture has received great develop- 

 ment in America and in Germany, but, although 

 there are a few notable exceptions, there has 

 been no corresponding activity on the part of our 

 chemical manufacturers, and the subject scarcely 

 receives the attention it deserves in our technical 

 schools and colleges. The Imperial College of 

 Science and Technology, we believe, made a 

 belated attempt to establish a course of instruc- 

 tion on industrial electrolytic methods — a matter 

 of the greatest importance to the future of our 

 chemical Industries, but apparently it was in 

 advance of any public recognition of its vital 

 necessity. Some idea of the growing importance 

 of electrolytic chlorine may be gleaned from the 

 fact that, before the war, Germany produced 

 nearly seven-tenths of the amount she needed by 

 this process. All the important methods of manu- 

 facturing electrolytic chlorine and alkali of which 

 published accounts are available are mentioned, 

 and shortly described, in Dr. Martin's mono- 

 graph, with explanatory diagrams, together with 

 a statement of what is known respecting their 

 current and energy efficiencies. 



The manufacture of liquid chlorine has 

 a special interest at the present time, and, 

 as is now well known, large quantities of this 

 substance are made in Germany by the Griesheim 

 process, and, to some extent, in England by the 

 Castner-Kellner method. Owing to the cir- 

 cumstance that dry chlorine does not attack iron, 

 the liquefied gas can be transported in large 

 boilers or steel cylinders. Apart from its use in 

 warfare, it finds extensive application in the 

 manufacture of monochloroacetic acid in the syn- 

 thetical indigo industry, and as a chlorinating 

 agent in the production of chloroform, chloral, 

 and other organic substances. The account by 

 Dr. Martin of the process of liquefaction gives 

 only a partial and imperfect account of the 

 methods actually employed. Even more bald is 

 the description of the methods of manufacture of 

 the alkali chlorates and perchlorates. Apart from 

 the bibliography, it is scarcely fuller than would 

 be given by an intelligent and reasonably well- 



