THE BELFAST ADDRESS. 189 



lar force becomes structural.* It required no great 

 boldness of thought to extend its play into organic 

 nature, and to recognise in molecular force the agency 

 by which both plants and animals are built up. In 

 this way, out of experience arise conceptions which are 

 wholly ultra-experiential. None of the atomists of 

 antiquity had any notion of this play of molecular 

 polar force, but they had experience of -gravity, as 

 manifested by falling bodies. Abstracting from this, 

 they permitted their atoms to fall eternally through 

 empty space. Democritus assumed that the larger 

 atoms moved more rapidly than the smaller ones, which 

 they therefore could overtake, and with which they 

 could combine. Epicurus, holding that empty space 

 could offer no resistance to motion, ascribed to all the 

 atoms the same velocity; but he seems to have over- 

 looked the consequence that under such circumstances 

 the atoms could never combine. Lucretius cut the 

 knot by quitting the domain of physics altogether, 

 and causing the atoms to move together by a kind of 

 volition. 



Was the instinct utterly at fault which caused 

 Lucretius thus to swerve from his own principles? 

 Diminishing gradually the number of progenitors, Mr. 

 Darwin comes at length to one * primordial form; ' but 

 he does not say, so far as I remember, how he supposes 

 this form to have been introduced. He quotes with 

 satisfaction the words of a celebrated author and divine 

 who had ' gradually learnt to see that it was just as 

 noble a conception of the Deity to believe He created 

 a few original forms, capable of self-development into 

 other and needful forms, as to believe He required a 

 fresh act of creation to supply the voids caused by the 

 action of His laws/ What Mr. Darwin thinks of this 

 * See Art. on Matter and Force, or ' Lectures on Light,' No. III. 



