108 JAMES CLERK MAXWELL 



CHAPTER VIII. 



SCIENTIFIC WOIIK MOLECULAR THEORY. 



MAXWELL in his article "Atom," in tho ninth edition of 

 the Encyclopedia Britannica, has given some account 

 of Modern Molecular Science, and in particular of the 

 molecular theory of gases. Of this science, Clausius 

 and Maxwell are the founders, though to their names 

 it has recently been shown that a third, that of 

 Waterston, must be added. In the present chapter 

 it is intended to give an outline of Maxwell's' contri- 

 butions to molecular science, and to explain the 

 advances due to him. 



Tho doctrine that bodies are composed <>f small 

 particles in rapid motion is very ancient. Democritus 

 was its founder, Lucretius de Kerum Natura ex- 

 plained its principles. The atoms do not fill space: 

 there is void between. 



"Qnapropter locus est intactus inane variins|Ue, 

 Ijuod si non essft, nulla ratione inoveri 

 ]{e.s possent ; n:iin<|Uc ofHchim quod corporU cxtat 

 Oflirere atijue oh.stare, il in onini tcmimre adessct 

 Omnibus. Haiul igitur quic|uain proct'ilere i>osset 

 IVincipiuin quoniain cwlendi nulla dart-t res." 



According to Boscovitch an atom is an indivisible 

 point, having position in space, capable of motion, and 

 possessing mass. It is also endowed with the power 

 of exerting force, so that two atoms attract or repel 

 each other with a force depending on their distance 



