350 DIRECT PROPERTIES OF MOLECULES 124 



it to be well fitted both to represent the facts and also to 

 avoid the philosophical objections which can justly be raised 

 to the assumption of atoms. We may conceive of a sub- 

 stance filling space continuously, and we shall then, in 

 spite of, or even by reason of, this representation, be forced 

 to the assumption that small ring-shaped or even thread- 

 shaped parts separate from the continuous mass which 

 cannot be further divided by any force on earth. These 

 yvortices, then, are the atoms of ponderable bodies, and 

 the substance between them remaining unmoved is the 

 ether. 



The unchangeable mass of these vortex atoms is deter- 

 mined alone by the states of the motion in which the world 

 was at their creation. The multiplicity of these states has 

 given rise to a multiplicity of kinds of vortex atoms, which, 

 in spite of their multiplicity, were all formed of the same 

 substance and in accordance with the same laws, and which 

 must bear witness to these laws for all time by the regu- 

 larity of their properties. The conformity to law exhibited 

 by the properties of atoms, and especially the law of the 

 periodicity of these properties, will thus find explanation by 

 this theory. 



3^ord Kelvin's theory of vortex atoms accounts also for 

 the forces exerted by the atoms on each other. Since the 

 vortex atoms have at once the properties of flexibility and 

 impenetrability, it is not paradoxical to ascribe to them the 

 same kind of elasticity as, on the older wave-theory of light, 

 ether is supposed to possess. We thus understand how 

 easily pendulous motions can pass from the atoms to the 

 ether and from the ether to the atoms, and comprehend how 

 luminous oscillations of the atoms require only vanishingly 

 little energy, as E. Wiedemann has shown. 1 



We may further assume, in respect of atoms of this kind, 

 that they conduct themselves like elastic bodies during an 

 encounter. These atoms can also exert an action at a 

 distance on each other by means of the medium which 

 exists between them but does not share their vortical 

 motions, and yet may transmit pressure ; for, as Lord 

 1 Compare 123 and 34. 



