MATHEMATICS AND CHEMISTRY 411 



the thread which is an advantage and we can quickly get the 

 mean of a number of independent readings. Such details make 

 a vast amount of difference in practice. Besides the great 

 advantage of simplicity of calculation afforded by the graphic 

 method there are others of importance. One sees at once, for 

 instance, any large experimental error or abnormality in any part 

 of the interaction and one knows, further, just which part and 

 how much of the interaction is being considered. This is most 

 important, as it is dangerous to lose sight of the physical 

 meaning of what one is doing, as can so easily happen when 

 using complicated mathematical formulae and equations. A 

 chemist can hardly be expected to be responsible for his actions 

 when he is out of his depth mathematically, as is so frequently 

 the case. 



The objection will naturally be raised that in the small book, for 

 which there is the greatest demand, the mathematical discussion 

 of chemical problems cannot be treated in the way here advocated. 

 It cannot. But we have too many of the small science books 

 which do all they can to breed mediocrity and foster superficiality. 

 Books should be written on a proper scale or not at all. I do 

 not wish to belittle in any way the value of books such as 

 Mellor's Higher Mathematics for Students of Chemistry and Physics 

 or his Chemical Statics and Dynamics — which have been of much 

 service to chemists — or to throw cold water on the undoubted 

 merits of Partington's new book on the mathematical side but 

 rather to censure the general attitude of the physical-chemical 

 school towards mathematics. In chemistry we have been served 

 with too much mathematics flavoured with too little of the sauce 

 of sound reason. There has been too much worship of mathe- 

 matical formulae and of the imposing appearance of mathematical 

 proofs ; there has been too little consideration of the hypotheses 

 and assumptions underlying so much of this mathematical 

 splendour. Lord Kelvin said that " when you can measure what 

 you are speaking about and can express it in numbers, you 

 know something about it ; but when you cannot measure it, 

 when you cannot express it in numbers, your knowledge is of a 

 meagre and unsatisfactory kind ; it may be the beginning of 

 knowledge but you have scarcely in your thoughts advanced to 

 the stage of science." It does not follow, however, because we 

 express our ideas in numbers that our ideas are necessarily 

 correct. So many of our numbers are not the numbers Lord 



