196 SPECULATIVE SCIENCE 



discovered. He determines in favour of a plurality of worlds, 

 for what has chanced to happen here must certainly have 

 chanced to happen elsewhere. 



The Second Book concludes by a contrast between the 

 miserable inefficiency of the gods, who pass a calm time in 

 tranquil peace, and the mighty power of the infinite sum of 

 clashing atoms, now building up new worlds, now slowly but 

 inevitably crumbling heaven and earth to dust by the unceasing 

 aggression of their never-ending flood. 



He thinks Memmius his friend ought to be very glad when 

 this conclusion is reached, and if fine poetry could please 

 Memmius he probably enjoyed the peroration ; otherwise it is 

 doubtful how far looking upon himself as a curious and com- 

 plicated result of the accidental collision of little bits of hard 

 stuff is calculated to make a man cheerful. 



We do not propose to follow Lucretius further. The appli- 

 cations which he makes of his theory are no doubt curious and 

 amusing, but they contain little that is true, while any criticism 

 of them would lead us to consider the whole field of physical 

 research ; nor do they add much to the clearness of his doctrine 

 as to the constitution of matter. Let us rather reconsider what 

 that doctrine was, and what merit it can claim. We shall find 

 that almost all the propositions which refer simply to the con- 

 stitution of matter are worthy of the highest admiration, as 

 either certainly true, or as foreshadowing in a remarkable way 

 doctrines since held by most eminent naturalists. Confine the 

 following statements to matter as we can observe it, to physical 

 science in fact, and they form a basis which even now would 

 require but little modification to be acceptable to a modern 

 student of physics. 



Nothing is made out of nothing, nor can anything perish ; 

 both matter and vacuum have a real existence, and gross matter, 

 such as we perceive, contains absolutely solid particles sepa- 

 rated by empty spaces. The absolutely solid particles are atoms. 

 These are impenetrable, hard, indivisible, indestructible. These 

 atoms are in continual motion, and the difference between 

 various bodies consists, first, in the difference of the shapes of 

 original atoms, and, secondly, in their arrangement and their 

 motion. The velocity with which atoms move is exceedingly 



