PHILOSOPHIC ANTS 189 



only some peculiarity of the registering machinery, 

 in ear or brain, which enables us to hear a note as 

 continuous. 



Still more remarkable are the facts of vision. As 

 I write I see the tulips in my garden, red against 

 the green grass : the red is a continuous sensation ; 

 but the physicists appear to be justified in telling us 

 that the eye is being bombarded every second with a 

 series of waves, not the few hundred or thousand that 

 give us sound, but the half-billion or so which conspire 

 to illuminate our vision. 



With sound, we alter the frequency of the waves 

 and we get a difference of tone which seems to be 

 merely a difference of more or less : but alter the 

 frequency of light-waves, and the whole quality of the 

 sensation changes, as when I look from the tulips to 

 the sky. The change of registering mechanism is 

 here more profound than the change in outer event. 



Or again, to choose an example that depends more 

 on size than rhythm, how very difficult it is to re- 

 member that the pressure of air on our bodies is not 

 the uniform gentle embrace of some homogeneous 

 substance, but the bombardment of an infinity of 

 particles. The particles are not even all alike : 

 some are of oxygen, others of nitrogen, of carbonic 

 acid gas, of water vapour. They are not all travelling 

 at uniform speeds ; collisions are all the time occurring, 

 and the molecules are continuously changing their 

 rate of travel as they clash and bump. 



