io8 SCIENCE AND IMMORTALITY 



argued, in accordance with Leibnitz's axiom " quod 

 non agit non existit," that a body is where it acts. 



Even more than gravitation, the undulatory 

 characteristics of light have seemed to require 

 an undulating medium with wonderful elastic 

 properties ; and Clerk-Maxwell, in an address on 

 " Action at a Distance," gives a very picturesque 

 description of the ether as light-bearer : " The 

 vast interplanetary and interstellar regions will 

 no longer be regarded as waste places in the 

 Universe, which the Creator has not seen fit to 

 fill with the symbols of the manifold order of his 

 kingdom. We shall find them to be already full 

 of this wonderful medium ; so full that no human 

 power can remove it from the smallest portion of 

 space, or produce the slightest flaw in its infinite 

 continuity. It extends unbroken from star to 

 star ; and when a molecule of hydrogen vibrates 

 in the Dog-star, the medium receives the impulses 

 of these vibrations, and after carrying them in 

 its immense bosom for several years, delivers them 

 in due course, regular order, and full tale into 

 the spectroscope of Mr Huggins at Tulse Hill." 



If the ether is to be the medium of gravitation 

 and light, it must extend through space to the 

 smallest star ; if it is to be the medium which 

 brings the smallest particles of matter into touchy it 

 must also permeate all matter ; and, of course, if 



