PRESIDENTIAL ADDRESS, B.A. 1871. 167 



concerned, sink into insignificance in the prospect 

 of any gain of deeper insight into the secrets of 

 nature. The triple coincidence of independent 

 reasoning in this case is valuable as confirmation 

 of a conclusion violently contravening ideas and 

 opinions which had been almost universally held 

 regarding the dimensions of the molecular structure 

 of matter. Chemists and other naturalists had 

 been in the habit of evading questions as to the 

 hardness or indivisibility of atoms by virtually 

 assuming them to be infinitely small and infinitely 

 numerous. We must now no longer look upon the 

 atom, with Boscovich, as a mystic point endowed 

 with inertia and the attribute of attracting or 

 repelling other such centres with forces depending 

 upon the intervening distances (a supposition only 

 tolerated with the tacit assumption that the inertia 

 and attraction of each atom is infinitely small and 

 the number of atoms infinitely great), nor can we 

 agree with those who have attributed to the atom 

 occupation of space with infinite hardness and 

 strength (incredible in any finite body) ; but we 

 must realise it as a piece of matter of measurable 



