no SCIENCE AND IMMORTALITY 



requires for his ether are infinitesimally small — 

 smaller even than electrons ; and the pressure in 

 the medium is tremendous — about 10,000 tons 

 per square centimetre. According to this theory, 

 matter is simply areas of diminished density in 

 the ether, which is something very like the direct 

 opposite of the ordinary ideas of matter and ether. 



Dr Larmor, again, thinks that the ether is "a 

 rotationally elastic medium," and is pervaded by 

 " a structure of tangled or interlaced vortex 

 filaments which might resist deformation by 

 forming a stable configuration." 



It is evident, accordingly, that there is much 

 difference of opinion with regard to the constitu- 

 tion of the ether. With regard to its general 

 characters there is less doubt. There are certain 

 characters it must have. The light undulations in it 

 are so small that there are 40,000 to 69,000 in one 

 inch, yet light travels at the rate of 186,000 miles 

 a second, which means that for the smaller waves 

 the ether must vibrate about 5,900,000000,000000 

 times in a second, or far more times in a second 

 than there are individual letters in all the books 

 in the British Museum. Any medium which can 

 do this must be extraordinarily elastic and dense. 

 Sir Oliver Lodge says that the ether is " so dense 

 that matter by comparison is like gossamer, or a 

 filmy imperceptible mist, or a milky way." And 



