TRANSACTIONS OF SECTION B. 479 



Section b.— CHEMICAL SCIENCE. 

 President of the Section — Professor G. D, Liveing, M.A., F.R.S., F.C.S. 



THURSDAY, AUGUST ii. 



The President delivered the following Address : — 



If I -were asked in what direction chemical science had of late been making the 

 most important advances, I should reply that it was in the attempt to place the 

 d-^niamics of chemistry on a satisfactory basis, to render an account of the various 

 phenomena of chemical action on the same mechanical principles as are acknow- 

 ledged to be true in other branches of physics. I cannot say that chemistry can 

 yet be reckoned amongst what are called the exact sciences, that the result pf 

 brino-ino- together given matters imder given circvmistances can yet be deduced in 

 more than a few special cases by mere mathematical processes from mechanical 

 principles, but that some noteworthy advances have in recent years been made, 

 which seem to bring such a solution of chemical problems more nearly within our 



rOticli. 



To show how large a gap in our ideas of chemical dynamics has been bridged 

 over within the last quarter of a centm-y, I will quote the words of one of the 

 laro-est-minded philosophers of his time, who was one of the earliest promoters of 

 this Association, and its President in 1841 : Whewell, in a new and much altered 

 edition of his 'Philosophy of the Inductive Sciences,' published in 1858, says: — 

 ' Since Newton's time the use of the word attraction, as expressing the cause of 

 the imion of the chemical elements of bodies, has been familiarly continued, and has 

 no doubt been accompanied ui the minds of many persons with an obscure notion that 

 chemical attraction is in some way a kind of mechanical attraction of the particles 

 of bodies. Yet the doctrine that chemical 'attraction' and mechanical attraction are 

 forces of the same kind has never, so far as I am aware, been worked out into a 

 system of chemical theory ; nor even applied with any distinctness as an explana- 

 tion of any particular chemical phenomena. Any such attempt, indeed, could only 

 tend to bring more clearly into Aiew the entire inadequacy of such a mode of 

 explanation. For the leading phenomena of chemistry are all of such a natiu-e, 

 that no mechanical combination can serve to express them without an immense 

 accumulation of additional hypotheses.' (' History of Scientific Ideas,' ii. 13.) And 

 further on he says:—' We must consider the power which produces chemical com- 

 bination as a peculiar principle, a special relation of the elements not rightly ex- 

 pressed in mathematical terms.' (Ibid. p. 14.) 



The influence by which our ideas have gone round so as to be now the very 

 opposite of those of the illustrious thinker whom I have just quoted, so that we 

 should ridicule the thought of looking for an explanation of chemical action on 

 any but mechanical principles, is undoubtedly the progress which has been made m 

 other branches of molecular physics. The iudestructibihty of matter has long 

 been a formida familiar to chemists, but that the conservation of energy should be 

 as imiversally true, even in regard to chemical actions, has only in recent years been 

 fully reco"-nised. This is certainlv no new principle, it was developed mathemati- 

 cally generations ago ; but the reaUsation that it is anything more than an abstrac- 

 tion, that it is the keynote of every rational explanation of physical phenomena, 

 has been the foimdation of recent progress in physical science ; and if all energy be 

 one there can be but one code of dynamical laws, which must apply to chemistry 

 as well as to all other branches of physics. The development of the mechanical 



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