PRINCIPLES OF THINGS. 



33 



well as in morals ; and hence the best physical schools m Greece, as well as 

 in more modern times, — those which have contended for the eternity of 

 matter, as well as those which have contended for its creation out of no- 

 thing, — have equally found it necessary to take for granted, what in fact 

 can never be proved, that matter in its lowest and ultimate parts consists 

 of solid, impenetrable, and moveable particles, of definite sizes, figures, and 

 proportions to space; from diflferent combinations of which, though 

 invisible in themselves, every visible substance is produced. 



This theory, which has been commonly distinguished by the name of the 

 Atomic philosophy, was first started in Greece by Leucippus or Democri- 

 tus, and afterwards considerably improved by Epicurus ; and as it bears a 

 striking analogy to many of the features which mark the best opinions of 

 the present day, and has probably given them much of their colour and 

 complexion, if it have not originated them, I shall take leave to submit to 

 you the following outline of it :■ — * 



The Atomic philosophy of Epicurus, in its mere physical contemplation, 

 allows of nothing but matter and space, which are equally infinite and un- 

 bounded, which have equally existed from all eternity, and from diflferent 

 combinations of which every visible form is created. These elementary 

 principles have no common property with each other : for whatever matter 

 is, that space is the reverse of ; and whatever space is, matter is the con- 

 trary to. The actually solid parts of all bodies, therefore, are matter ; their 

 actual pores space ; and the parts which are not altogether solid, but an 

 intermixture of solidity and pore, are space and matter combined. Anterior 

 to the formation of the universe, space and matter existed uncombined, cr 

 in their pure and elementary state. Space, in its elementary state, is abso- 

 lute and perfect void ; matter, in its elementary state, consists of inconceiv- 

 ably minute seeds or atoms, so small that the corpuscles of vapour, light, 

 and heat are compounds of them ; and so solid, that they cannot possibly 

 be broken or abraded by any concussion or violence whatever. The ex- 

 press figure of these primary atoms is various : there are round, square, 

 pointed, jagged, as well as many other shapes. These shapes, however, 

 are not diversified to infinity ; but the atoms themselves of each existent 

 shape are infinite or innumerable. Every atom is possessed of certain in- 

 trinsic powers of motion. Under the old school of Democritus, the per- 

 petual motions hence produced were of two kinds : a descending motion, 

 from the natural gravity of the atoms ; and a rebounding motion, from colli- 

 sion and mutual clash. Besides these two motions, and to explain certain 

 phaenomena to which they did not appear competent, and which were not 

 accounted for under the old system, Epicurus supposed that some atoms 

 were occasionally possessed of a third, by which, in some very small de- 

 gree^ they descended in an oblique or curvihnear direction, deviating from 

 the common and right line anomalously ; and in this respect resembling 

 the oscillations of the magnetic needle. 



These infinite groups of atoms, flying through all time and space indif- 

 ferent directions, and under different laws, have interchangeably tried and 

 exhibited every possible mode of rencounter ; sometimes repelled from each 

 other by concussion, and sometimes adhering to each other from their own 

 jagged or pointed construction, or from the casual interstices which two or 

 more connected atoms must produce, and which may be just adapted to 

 those of other figures, as globular, oval, or square. Hence the origin of com- 



* This outline is given more at length in the author's Prolesromena to- bis !ransl?tj"Ti ci' 

 "'^ The Nature of Things,*' p eix- following. 



