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and economic points of view, is well worth perusal by all who are interested in the 

 national welfare. 



Although, of course, the greater part of the book deals with the technical side 

 of zinc extraction, other chapters, such as those on the physical and chemical 

 properties of zinc, and on the Future of the Zinc Industry in Great Britain, are 

 given, and should make the volume of value to the chemist and economist as well 

 as to the metallurgist. Several clear photo-micrographs are included and a useful 

 bibliography is appended. The index might have been made a trifle fuller. 



F. A. M. 



The Manufacture of Intermediate Products for Dyes. By John Cannell 

 Cain, D.Sc, Editor of the Journal of the Chemical Society, etc, 

 [Pp. xii + 263, with 25 illustrations.] (London : Macmillan & Co., 1918. 

 Price \os. net.) 



Those who hope to find in Dr. Cain's book "The Secret of the Aniline Dyes" 

 will be doomed to disappointment, yet there can be no doubt that there is 

 contained within the 263 pages of this modest-sized work far more valuable 

 information than could be hoped for in any " 257 secret recipes " or other alleged 

 short cut to the successful exploitation of the dye situation. 



It will be recalled that one of the first problems which faced the manufacturer 

 of dyes in this country on the outbreak of war was the provision of the so-called 

 " intermediates " from which the final dyes are made. When it is remembered 

 that about 85 per cent, of the capital outlay in a dye-works is in plant for the 

 production of intermediates, it will be realised that a work such as Dr. Cain's, 

 which summarises the patent literature on the subject, is of the greatest value. 



The special objects of the book are summed up in the preface : " It is ... of 

 prime importance to the would-be manufacturer to have in a convenient form 

 detailed information as to the preparation of the materials he proposes to make, 

 so that he may be sure he will not spend time and money in rediscovering, 

 perhaps, some process that may have been already elaborately described in an 

 obscure book or periodical. It appeared to the author that a concise account of 

 the literature dealing with the manufacture of intermediate products for dyes 

 might therefore be of considerable use, and in this book he has endeavoured to 

 present such an account in detail so as to render it unnecessary to refer to the 

 original descriptions. It may, perhaps, be stated that he doubts whether any 

 single library in England contains the whole of the literature consulted." 



It is unnecessary to discuss the various chapters as the entire subject has been 

 covered in great detail, the information appears to be very up-to-date, and a 

 perusal of the pages is likely to be of interest to purely academic chemists — if any 

 such exist now— as much as to manufacturers and students. As an example we 

 may quote the various patented processes for the catalytic reduction of nitro- 

 benzene to aniline on pp. 44, 45, though we may note that the author has not 

 included certain less important patents on the subjects. 



Here and there Dr. Cain appears to have overlooked one or two patents, 

 such as on p. 139, where, in referring to the production of 0. nitrobenzaldehyde 

 from 0. nitrophenylnitromethane he makes no reference to the original patent 

 (E.P. 24871/1910). Surely, also, it would be as well to give the patent 

 references (E.P. 6076/191 1 and 17985/1911) to the production of 0. nitrophenyl- 

 nitromethane itself? Again, one seeks in vain for any reference to the production 

 of Isatine, which is of some importance in connection with modern vat-dyes. 



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