NATURE 



421 



THURSDAY, JULY 31, 1919. 



A PPLIED C HEM IS TR Y. 



(1) Boiler Chemistry and Feed-r'y'ater Supplies, 

 By J. H. Paul. Pp. ixi-242. (London: Long- 

 mans, Green, and Co., 1919. J Price 145. net. 



(2) Reports of the Progress of Applied Chemistry. 

 Issued by the Society of Chemical Industry. 

 Vol. iii. Pp. 495. (London : Society of Chemi- 

 cal Industry, 1918.) Price lOi". bd. 



(3) Trinitrotolueries and Mono- and Dinitro- 

 toluenes : their Manufacture and Properties. By 

 G. Carlton Smith. Pp. vii+133. (London: 

 Constable and Co., Ltd., 1918.) Price 8^. bd. 

 net. 



(1) |\/|R- J- H. PAUL is a well-known autho- 

 •i-'-"- rity on tne chemical principles involved 

 in the management and control of steam-boilerb, 

 especially in regard to the nature and selection 

 of their teed-waters and of their treatment in the 

 prevention of boiler-scale and corrosion. 



In the book before us, which has been written 

 mainly for the use of engineers and practical men 

 possessing, presumably, a limited knowledge of 

 chemistry and of chemical terminology, the author 

 has sought to explain, in non-techmcal language, 

 the character of the reactions which occur in 

 natural waters containing a variety of soluble 

 saline substances, when heated for the purpose of 

 steam-raising at the relatively high temperatures 

 and pressures of modern boiler practice. The 

 nature of the changes which may occur under 

 these conditions is probably more complex than 

 is usually assumed, and certain of them are pos- 

 sibly complicated by the circumstance that they 

 are of the character of reversible reactions, and 

 subject to the laws of mass action and to the vari- 

 able influence of temperature and concentration. 



In some seventeen chapters the author describes 

 the various forms of natural water, with special 

 reference to their suitability for steam-raising ; 

 the nature of their saline constituents ; the com- 

 position of the various scales and boiler deposits ; 

 modes of softening water ; the character and in- 

 fluence of the permanently soluble salts ; the 

 action of carbonic acid ; its behaviour towards 

 iron; the general question of boiler corrosion, its 

 causes and prevention ; good and bad boiler prac- 

 tice, etc. The book is largely based upon personal 

 experience, and contains the results of numerous 

 original analyses of water-supplies of all kinds 

 and from all parts of the world, and of various 

 deposits, internal and external. It can be recom- 

 mended as a trustworthy guide to those concerned 

 in boiler work. It will be gathered that it deals 

 more with practice than with theory, and it must 

 be stated that the rational explanation of certain 

 of the phenomena given by the author is open to 

 question ; indeed, it is admitted that the section 

 of the work dealing with the action of carbonic 

 acid on iron is largely speculative, and may have 

 to be modified when more is known on the sub- 

 XO. 2596, VOL. 103] 



ject. In spite of his avoidance, as a rule, of 

 technical language, the author is constrained at 

 times to express reactions by means of chemical 

 equations, of some of which the validity cannot 

 be considered as established, and it somewhat 

 savours of dogmatism to neglect the evidence of 

 other observers. "It has been felt that the prin- 

 ciple of giving authorities is a subterfuge for pass- 

 ing on to others a responsibility an author has not 

 the courage to assume on his own account. " This 

 is surely a very unscientific attitude of mind. 

 There should be here no question of subterfuge 

 or of courage or the lack of it. He who wishes 

 to gain, as fully as possible, a knov.ledge of the 

 facts desires to have an independent corrobora- 

 tion of them, and for Mr. Paul to arrogate to 

 himself an ex cathedra position as the sole autho- 

 rity detracts from, rather than enhances, the 

 weight of his testimony. As a searcher for the 

 truth it is incumbent on him to cite whatever evi- 

 dence bears upon it. 



(2) Vol. iii. of the annual reports issued by 

 the Society of Chemical Industry deals with the 

 progress of applied chemistry made during 1918. 

 As in the case of the two previous reports, it is 

 mainly based upon material published by the 

 society in its fortnightly journal issued during that 

 year. Its plan is practically identical with that of 

 its predecessors, and many of its contributors are 

 the same as in previous cases. Two important 

 sections are added, viz. agricultural chemistry and 

 foods. On the other hand, three are omitted, 

 viz. ceramics, building materialsj and fermenta- 

 tion industries, as the compilers of these sections 

 failed to send in their copy in time to be included 

 in the present volume. Considering the range of 

 material to be dealt with, and the number of con- 

 tributors engaged, Idches of this kind are probably 

 unavoidable, but they detract, of course, from the 

 value of the report as a comprehensive and com- 

 plete summary of the particular year's work, and 

 necessitate, as in the present case of the added 

 sections on foods and agricultural chemistry, the 

 compression of the work of several years in a 

 single report. There is, to this extent, a certain 

 lack of uniformity in treatment and an absence of 

 continuity which are to be regretted, but for which 

 the editor and the publication committee are 

 scarcely to be held responsible. 



In the present volume the various departments 

 of applied chemistry treated of are grouped under 

 twenty-two sections. It is obviously impossible, in 

 the limited space at our disposal, to deal with them 

 all in detail, and we propose to select those for 

 the purpose of comment which are of general in- 

 terest or of particular importance at the present 

 time of "reconstruction." 



The value of these annual reports is greatly in- 

 creased when particular sections are handled in 

 successive years by the same author, provided 

 that he is competent and has the necessary critical 

 skill ; and the excellence of his summary is aug- 

 mented if he prefaces it by a general statement 

 of the more striking marks of progress which 



