FORCE 41 



vibrations ; air and water have no rigidity, yet they 

 are transparent, i. e., transmit transverse vibrations; 

 hence it must be the ether inside them which really 

 conveys the motion, and the ether must have proper- 

 ties which, if it were ordinary matter, we would style 

 inertia or rigidity. No highly rarefied air will serve 

 the purpose; the ether must be a distinct body. Air 

 may exist, indeed, in planetary space, even to infinity, 

 but if so, it is of almost infinitesimal density com- 

 pared with the ether there."* 



"So at a height of only 4,000 miles above the sur- 

 face, the atmospheric density is a number with 127 

 ciphers after the decimal point before the significant 

 figures begin." The density of ether, as calculated by 

 Sir William Thomson, is represented by a decimal 

 " with only 17 ciphers before the significant figures. 

 In interplanetary space, therefore, all the air that 

 exists is utterly negligible; the density of the ether 

 there, though small, is enormous by comparison." 



It is known that ordinary forms of matter are not 

 necessary for the transmission of light, for it passes 

 readily through the most perfect vacuum. 



It also passes through the diamond — the hardest 

 known solid, but with less velocity than through the 

 vacuum. If ether serves as a medium for light in a 

 vacuum, it is probable that it also serves as a medium 

 in the diamond. There is nothing to justify the con- 

 clusion that the molecules of a transparent solid 

 serve as a medium for radiant energy. The high rate 

 of speed at which light traverses such bodies excludes 

 the belief that solids act as conductors of light as 

 they do of heat. 



The following are some of the conclusions with 

 regard to ether : 



* Modern Views of Electricity, by Oliver J. .Lodge, p. 340. 



