Polytechnic Association. 871 



of that mysterious intuition which, overleaping the limits of logie r 

 often arrives at correct conclusions, even before their truth has been 

 demonstrated. 



During all the discussions on " atomicity," hardly a doubt has been 

 raised as to the actual existence of the atom. It was not, therefore, 

 surprising that the chemical world received a sensible shock at the 

 stand made by Brodie in 1868.* However, a careful examination of 

 his paper is likely to lead to the conclusion that the objections to the 

 atomic theory therein enumerated are not more formidable than those 

 which can be urged against his own ingenious, but complicated, 

 method of chemical operations. Precision in signs and definitions 

 leads to exact results in the abstract ; nevertheless a mathematical 

 formula often requires modification to meet the varying conditions 

 found in actual practice, and even then it only gives a near approxima- 

 tion to the truth. 



Renewed attention to this subject was doubtless the means of draw- 

 ing, from the then president of the London Chemical Society, a 

 paper " On the Atomic Theory," which is generally regarded as the 

 best exposition and defense of the doctrine yet made, and which may 

 be consulted with profit by those desiring to obtain a clear statement 



of the principal results of chemical research adduced for its con- 

 firmation. f 



A vigorous attack on the atomic theory has since been made by 

 Mills, the real tendency of which is to raise doubts concerning the 

 existence of matter itself.;]: He quotes, with evident satisfaction, from 

 a work by Digby, "On the Nature of Bodies," printed in 1645 y 

 wherein quantity is defined "as but one whole that may, indeed, be 

 cut into so many several parts ; but those parts are really not there 

 till by division they are parceled out ; and then the whole (out of 

 which they are made) ceaseth to be any longer, and the parts succeed 

 in lieu of it, and are every one of them a new whole." From this 

 statement proceeds a train of geometrical reasoning concerning exten- 

 sion and division, which leads to the old dilemma regarding finite and 

 infinite indivisibles. 



Fortunately a new science, unknown to Digby, has demonstrated 

 that matter has other than mere physical properties, which are so clear 



* The Calculus of Chemical Operations. By Prof. B. C. Brodie. Journal of the 

 Chemical Society, London, vol. xxi, p. 367. 



f On the Atomic Theory. By Prof. A. W. "Williamson. Jour. Chem. Soc. 

 London, vol. xxii, p. 328. 



X On the Atomic Theory. By Edmund J. Mills, D. Sc. Philosophical Magazine, 

 vol. xlii, No. 278, p. 112. 



