14 THE ACTIVE FORCES OF LIVING ORGANISMS 



Ether or 

 light sub- 

 stance as 

 the trans- 

 mitting 

 medium of 

 light. 



The air, to return again to the more familiar 

 example, is always in a state of tension, irrespective 

 of its weight. If you take a vessel from which the 

 air has been withdrawn and make an opening in the 

 bottom, it will naturally fill again as rapidly as if 

 the aperture had been in the top. But the tension 

 of the ether is far greater than that of our atmosphere. 

 Now, if we suppose a number of molecules or of 

 molecules and atoms to be vibrating at a given point 

 A — to be hammering, that is to say, the ether — and 

 another lot to be hammering it, though in a different 

 manner, at a given point B, let us say, it is evident 

 that when the general tension of the ether is taken 

 into consideration, conditions favourable to an inter- 

 change or discharge of impulses might be said to exist. 

 Certain media — such, for instance, as a copper wire 

 — may be used to isolate a stratum of the ether 

 between any two points, and thus to render com- 

 munication the more easy. When, however, a suit- 

 able apparatus is raised to a certain height above the 

 ground, so as to be removed in all probability from 

 the ethereal influence of the earth and objects on 

 it, even the use of a connecting wire, as Marconi's 

 experiments have shown, is unnecessary. 



Those who refuse to adopt the view that light is 

 transmitted by means of the ether are, neverthe- 

 less, obliged to base their conception of it on the 

 existence of a second medium, called by them light 

 substance, which in its chief properties of divisibility 

 and ubiquity so closely corresponds to one's notions 



