July 15, 1920] 



NATURE 



609 



Fuel Problems. 

 Fuel Production and L'tilizatioti. By Dr. H. S. 

 Taylor. (Industrial Chemistry Series.) Pp. 

 xiv + 297. (London: Bailli^re, Tindall, and 

 Cox, 1920.) Price los. 6d. net. 



THIS volume is intended more especially as 

 a post-graduate book which shall "sup- 

 plement academic trainings with the broad facts 

 of fuel production and utilisation." The main 

 sources from which the author has drawn his 

 material are the valuable bulletins issued by the 

 United States Geological Survey and the Bureau 

 of Mines, supplemented by other American and 

 Canadian sources of information. Everyone 

 familiar with fuel problems realises the great 

 value of these publications, and although many 

 of the author's quotations from these and his 

 other sources are lengthy, his judicious selection 

 of material has enabled him to compile a volume 

 which cannot fail to be of value to a much wider 

 circle than post-graduate students. 



A great change in the fuel problem has fol- 

 lowed from the enormous rise in the price of coal, 

 and it is difficult to see what the far-reaching 

 ultimate effect will be. Certain it is that man 

 will be driven to consider the utilisation of much 

 material which has hitherto received but little 

 attention, and to give closer attention to using the 

 last heat unit possible in every ton of coal. While 

 coal was cheap economists preached to deaf ears ; 

 economic necessity will produce effects which 

 years of preaching failed to accomplish. Dr. 

 Taylor's book should go a long way to help those 

 who are prepared to take the serious view which 

 the situation demands of these problems, and it is 

 of value not only as recording what has been done 

 in the near past, but also as indicating possibilities 

 in fuel utilisation in many directions. 



One of the features of the book is the broad 

 outlook of the author on many of the problems 

 which, whilst at present of very minor importance, 

 bear evidence of becoming of considerable prac- 

 tical importance with the great alteration in con- 

 ditions in the fuel situation. The utilisation of 

 the minor fuels — peat wood, coke for industrial 

 purposes, and pulverised coal — together with the 

 many problems associated with the low-tempera- 

 ture distillation schemes, are more adequately 

 dealt with by Dr. Taylor than by most writers 

 of general books on fuel, the considerable space 

 devoted to these problems being amply justified 

 by their potential importance. 



From the scientific point of view the "syn- 

 thetic " fuels are of considerable interest. In the 

 future some may become of great importance. 

 The merits of alcohol as a fuel are now very widely 

 NO. 2646, VOL. 105] 



recognised, and the author gives an excellent 

 account of this question. Closely connected — in- 

 deed, part of the problem — is acetylene as fuel, 

 either directly, for small motor vehicles have been 

 driven by this gas, or more specifically as a pos- 

 sible source of alcohol. Several processes for the 

 conversion are referred to, the steps usually in- 

 volving the formation of aldehyde by absorption in 

 acids, generally in the presence of mercury salts, 

 and the conversion of the aldehyde into alcohol 

 by reduction by Sabatier's method with hydrogen 

 in the presence of nickel as a catalyst. 



Of a similar character is the production of 

 hexahydrobenzene (hexamethylene) by the hydro- 

 genation of benzene. The author points out the 

 advantages of such a fuel of constant composition 

 and properties, but he does not refer to the one 

 great disadvantage of this compound, namely, its 

 high freezing point (64° C). He refers to it as 

 suitable for aeroplanes, but this high freezing 

 point obviously entails serious difficulties. In ad- 

 mixture the claim for homogeneous composition 

 is gone, and. even alone it is difficult to see what 

 advantages it possesses over benzene, which has 

 approximately the same freezing point, or even 

 over commercial "benzol," which freezes below 

 0° C. and has no greatly varying degree of vola- 

 tility. J. S. S. B. 



Hurter and Driffield. 



A Memorial Volume containing an Account of the 

 Photographic Researches of Ferdinand Hurter 

 and Vero C. Driffield: Being a Reprint of their 

 Published Papers, together with a History of 

 their Early Work and a Bibliography of Later 

 Work on the Same Subject. Edited by W. B. 

 Ferguson. Pp. xii + 374. (London : The Royal 

 Photographic Society of Great Britain, n.d.) 

 Price 255. 



DR. HURTER died twenty-two years ago, and 

 Mr. Driffield afterwards did little or nothing 

 more in connection with their joint labours than 

 complete and publish the work that was almost 

 finished. It is possible now, therefore, to regard 

 their work as a whole, and to see something of 

 the relationship that it bears to the general pro- 

 gress of photography from the scientific point of 

 view. 



Hurter and Driffield did two very considerable 

 things. They devised the method of drawing what 

 they called, and what is now universally known as, 

 the " characteristic curve " of a developable sensi- 

 tive surface. This may at first appear a very easy 

 thing to do, but it is often the things that are easy 

 to do which are the most difficult to get at and of 



