REVIEWS 501 



The Chemistry and Manufacture of Hydrogen. By P. Litherland Teed, 

 A.R.S.M., A.I.M.M., Major R.A.F. [Pp. vii + 152, with 22 figures in the 

 text.] (London : Edward Arnold, 1919. Price 10s. bd. net.) 



The unique circumstances of the last four years have stimulated the industrial 

 utilisation of many chemical products which were formerly regarded as merely 

 of theoretical or academic interest, and which, a few years ago, were practically 

 unknown in technological practice. Few of these substances have proved of 

 such value as hydrogen, and probably in no case has the number of applications 

 to industrial processes been greater. The demand for solid fats has been largely 

 met by the production of " unsaturated " oils and fats by means of Sabatier's 

 method of hydrogenation by the aid of catalysts ; the Haber process for the 

 synthesis of ammonia from its elements has been utilised in Germany to overcome 

 the shortage of nitrogen compounds required for explosives and fertilisers, while 

 gaseous hydrogen has been largely employed for balloons and airships. Con- 

 sequently there have been numerous developments in the methods of manufacture 

 of the gas, and a fairly voluminous literature is now to be found in the various 

 technical journals. As this information is very much scattered, and the subject 

 has hitherto received scant treatment in books on chemical technology, the 

 author, in the monograph under review, has endeavoured to provide a remedy 

 by presenting a useful and very readable summary of the present state of know- 

 ledge of the subject. 



The earlier parts of the book are occupied by chapters dealing with the 

 natural occurrence and chemistry of hydrogen. So far as the former is concerned, 

 it may be pointed out that some of the data given are not altogether reliable 

 owing to the lack of good methods of determining the amount of the gas in 

 rocks and meteorites. Since in most cases complete evolution of the gas is only 

 obtained by heating the solid to high temperatures, and the water, which is almost 

 invariably present, reacts with iron compounds, the percentage of hydrogen 

 found by such analysis does not represent the amount originally present as gas. 

 The chapter on the chemistry of hydrogen, apparently inserted for the sake 

 of completeness, is too short to be of much practical value, and might well have 

 been omitted, as the information contained therein can be obtained from textbooks 

 of general chemistry. Data for certain of the physical constants of the gas are 

 given in an appendix. 



The remainder of the book is occupied by an interesting account of the 

 "large scale" methods for the production of the gas. The descriptions of the 

 various processes are well illustrated, and, though concise, are sufficiently de- 

 tailed to form a valuable source of information. The methods of manufacture 

 are divided into three groups, chemical, chemico-physical, and physical, according 

 to the nature of the principles on which they are based. Since the first of 

 these includes the Silicol, Iron Contact and Badische Catalytic processes, the 

 greatest amount of space is devoted to it. The Linde-Frank-Caro process is 

 the only one of importance in the second group, while physical methods are only 

 used where the required output is relatively small, or where the gas can be 

 obtained as a by-product. 



Although the references to the patent and other literature are fairly full, they 

 might have been given in a more systematic form ; for example, the page 

 numbers and dates are omitted in many cases. A few misprints occur, particu- 

 larly in proper names, as, for instance, " Crooks " for " Crookes," and " Fouque " 

 for " Fouque" " on page 7, " Moisson " for " Moissan " on page 19, and " Jacquerod " 

 for "Jaquerod" on page 145. On page 17 the melting-point of copper is errone- 



