f 697 ] 



LXXIII. Notices respecting' New Books. 



Catalysis in Theory and Practice. By Eric K. Eldeal, Ph.D., and 



Hugh S. Taylor, D.Sc. Pp. xv + 496. London: Macmillan 



and Co., Ltd., 191,9. 17s. net. 



'TVHIS book comes iri the fulness of time. Catalytic processes 



have played an important part in the development of 



chemical science for the last hundred years., The extent of the 



application of such processes in recent years is very remarkable. 



It is a pity that no satisfactory explanation of this action is yet 

 forthcoming-. This is possibly, in part, owing to the wide scope of 

 the term catalysis. Whenever a chemical change is accelerated 

 (or the reverse) by the introduction of a foreign substance the 

 process is spoken of as catalytic (positive or negative, as the case 

 may be). Now, in the multifarious cases that arise, it is not likely 

 that the process is identical in kind ; hence a corresponding multi- 

 plicity of explanations is required. It is true that the authors 

 attempt to restrict the field, and to lay down the requirement that 

 the chemical composition of the catalytic agents is unchanged on 

 completion of the reaction process. In some cases, however, of 

 negative catalysis the retarding agents are not present at the 

 beginning, and increase as time goes on ; these hardly seem to fit 

 in with the definition given. However, the definition covers 

 what is denoted by the term positive catalysis very well. 



The authors do not commit themselves to anyone theory, but 

 outline several theories, each of which has something to be said 

 for it. Concerning the thoria-ceria mantle which is still very 

 much a conundrum, no explicit reference is made to Rubens's 

 theory that the poor general emissivity of thoria enables a high 

 temperature to be reached, at which the selective luminous radiation 

 of ceria is extremely high (though not higher than that of a black 

 body at the aforesaid high temperature). If this is right, the 

 mantle is not an example of catalysis at all. 



Amongst the modern processes the hydrogenation of oils is of 

 tremendous importance, clue to the increase produced in our food- 

 supply. Also during the war the necessity for ensuring a supply of 

 nitrates for explosives rendered imperative the creation of a fresh 

 supply : just as in Germany the same imperative necessity had pre- 

 sented itself before a war could be undertaken; and in both cases the 

 utilization of the nitrogen from the air involved the use of catalytic 

 processes. These the authors are specially competent to deal with. 

 We cannot here examine the book in detail. The writers deal 

 in a masterly way with the problem. We conclude by quoting 

 the final words of their own preface : " Will the catalytic agencies 

 be found which shall accelerate the velocity of atomic decay and 

 render available the enormous stores of intra-atomic energy? 

 Such is the fitting problem for the years that lie ahead." 



Ten British Physicists. By Alexander Macearlaxe. 

 Chapman & Hall. Price 7s. 6d. net. 

 The ten scientists whose lives are dealt with in the book before us 

 Phil. Mag. S. 6. Vol. 39. No. 234. June 1920. 2 Z 



