68 Sir Oliver Lodge [Feb. 21, 



force. If allowed to "precess" it will respond by moving perpen- 

 dicularly to a deflecting force. So it is with the charge and the 

 magnetic pole. Try to move the charge suddenly, and it immediately 

 sets off at right angles. A moving charge is a current, and the 

 pole and the current try to revolve round one another — a true gyi'O- 

 static action due to the otherwise unrecognisable etherial spin. The 

 fact of such magnetic rotation was discovered by Faraday. 



I know that it is usually worked out in another way, in terms of 

 lines of force and the rest of the circuit ; but I am thinking of a current 

 as a stream of projected charges ; and no one way of regarding such 

 a matter is likely to exhaust the truth, or to exclude other modes 

 which are equally valid. Anyhow, in whatever way it is regarded, 

 it is an example of the three rectangular vectors. 



The three vectors at right angles to each other, which may 

 be labelled Current, Magnetism, and Motion respectively, or more 

 generally E, H, and Y, represent the quite fundamental relation 

 between ether and matter, and constitute the link between Electricity, 

 Magnetism, and Mechanics. Where any two of these are present, 

 the third is a necessary consequence. This principle is the basis of 

 all dynamos, of electric motors, of light, of telegraphy, and of most 

 other things. Indeed, it is a question whether it does not underlie 

 everything that we know in the whole of the physical sciences ; and 

 whether it is not the basis of our conception of the three dimensions 

 of space. 



Lastly, we have the fundamental property of matter called inertia, 

 which, if I had time, I would show could be explained electro- 

 magnetically, provided the etherial density is granted as of the order 

 10^^ grammes per cubic centimetre. The elasticity of the ether 

 would then have to be of the order 10^^ c.g.s. : and if this is due to 

 intrinsic turbulence, the speed of the whirling or rotational elasticity 

 must be of the same order as the velocity of light. This follows 

 hydrodynamically ; in the same sort of ^ay as the speed at which a 

 pulse travels on a flexible running endless cord, whose tension is 

 entirely due to the centrifugal force of the motion, is precisely equal 

 to the velocity of the cord itself. And so, on our present view, the 

 intrinsic energy of constitution of the ether is incredibly and porten- 

 tously great ; every cubic millimetre of space possessing what, if it 

 were matter, would be a mass of a thousand tons, and an energy 

 equivalent to the out-put of a million-horse-power-station for 40 mil- 

 lion years. 



The universe we are living in is an extraordinary one ; and our 

 investigation of it has only just begun. We know that matter has a 

 psychical significance, since it can constitute Irain, which links 

 together the physical and the psychical worlds. If anyone thinks 

 that the ether, with all its massiveness and energy, has probably no 

 psychical significance, I find myself unable to agree with him. 



