54 THE LIMITATIONS OF SCIENCE 



magnetic ether must have electro-magnetic friction, to 

 receive the electro-magnetic vibrations of the electric 

 atom and must be devoid of electro-magnetic friction 

 so as not to absorb electro-magnetic waves when in 

 transit. Again, he says the mechanical atom was de- 

 fective, in that it could not account for electricity, but 

 he also says that the electrical atom does not explain 

 cohesion, weight, and, I might add, any other me- 

 chanical property. Which shall we choose? Lastly, 

 not to prolong the discussion, just as the mechanical 

 ether and atom led us to such contradictory attributes 

 as enormous rigidity and inappreciable density, so the 

 electro-magnetic ether and atom require us to give the 

 latter an electric force whose magnitude is to that of 

 weight as ten raised to the forty-second power is to 

 one. 



Temperamentally, Professor Thomson has little in 

 common with his colleague, Professor Larmor; as all 

 know, we owe to him a long series of most delicate and 

 profound experimental investigations in this field. 

 Like Lord Kelvin, he is usually content to construct a 

 model for each special phenomenon, and, as he is rather 

 indifferent whether these agree in operation, it is diffi- 

 cult to form any consistent idea of his theory. He 

 seems to regard matter as if it were a sort of building- 

 blocks which may be put together as fancy directs. His 

 best-known conception of matter and electricity is his 

 picture of an atom as a central sphere of uniformly 



