ATMOSPHERE versus ETHER. 391 



tuitously endowed with whatever properties are required 

 for the fitting of their theories properties that are self- 

 contradictory and without any counterpart in anything 

 seen or known outside of the fertile imagination of these 

 reckless theorists. 



We know of nothing that can penetrate every form of 

 matter without adding either to its weight or its bulk; we 

 know of nothing that can communicate motion to ponder- 

 able matter without itself being ponderable i.e., having 

 the primary property of matter, viz., mass, or weight, and 

 consequent vis viva when moving; we know of nothing 

 that can set bodies in motion without proportionally resist- 

 ing the motion of bodies through it; and if the waving of 

 the ether is (as Tyndall describes it) "as real and as truly 

 mechanical as the breaking of sea-waves upon the shore," 

 the material of the breakers must be like the "jelly" to 

 which he compares it, and have some viscosity, or resistance 

 to penetration, or pushing aside. 



We have not a shadoAv of direct evidence of the existence 

 of the "interatomic" spaces occupied by the other, and in 

 the midst of which the atoms are made to theoretically 

 swing, nor even of the existence of the atoms themselves. 



The "ether" of to-day, with its imaginary penetration 

 and its material action without material properties, has 

 merely taken the place of the equally imaginary phlogiston, 

 caloric, electric, and magnetic fluids, the "imponderables" 

 of the past. I have little doubt that ere long the modern 

 modification of these physical superstitions will share their 

 fate, and AVC shall all adopt the simple conception that 

 heat, light, end electricity are, like sound, merely trans- 

 missible states or affections of matter itself regarded 

 bodily, as it is seen and felt to exist. 



This may possibly throw a good many mathematicians 

 out of work or into more useful work; but, however that 

 may be, it will .certainly -aid the general diffusion of science 

 as the intellectual inheritance of every human being. At 

 present the explanations of the simple phenomena of light 

 and heat are incomparably more difficult to understand 

 and to account for than the facts which they attempt to 

 elucidate. 



