so SCIENCE AND IMMORTALITY 



but any particular molecule, after going over an 

 incredibly short distance — the measure of which 

 has been made — meets another, not exactly plump, 

 but a little on one side, so that they behave to 

 one another somewhat in the same way as two 

 people do who are dancing Sir Roger de Coverley : 

 they join hands, swing round, and then fly away 

 in different directions." " In the case of a liquid, 

 it is believed that the state of things is quite 

 different. We said that in the gas the molecules 

 are moved in straight lines, and that it is only 

 during a small portion of their movement that 

 they are deflected by the other molecules ; but in 

 a liquid we may say that the molecules go about 

 as if they were dancing the grand chain in the 

 Lancers. Every molecule, after parting company 

 with one, finds another, and so is constantly going 

 about in a curved path, and never sent quite clear 

 away from the sphere of action of the surround- 

 ing molecules. In the case of a solid, quite a 

 different thing takes place. In a solid, every 

 molecule has a place which it keeps ; that is to say, 

 it is not at rest any more than a molecule of a 

 liquid or a gas, but it has a certain mean position 

 which it is always vibrating about and keeping 

 fairly near to, and it is kept from losing that 

 position by the action of the surrounding 

 molecules." 



