S6 SCIENCE AND IMMORTALITY 



of a grain, can be detected. Not only so, but it 

 matters not at all how far off the throbbing heart 

 of the molecule may be. However far off, the 

 spectroscope can record and read and interpret 

 the ether waves produced by the throbbing mole- 

 cules. The molecules — the tiny fierce molecules 

 — throbbing in the sun 92,000,000 of miles away, 

 have been made to write their name in ripples ; 

 and we know now that in the sun are hydrogen, 

 sodium, iron, copper, magnesium, zinc, calcium, 

 and about thirty other elements. Stranger still, the 

 spectroscope discovered in the sun an element then 

 unknown on earth, which the discoverers called 

 helium ; and some years later this very element was 

 discovered in a mineral called clevite ; and, a few 

 years later still, it was found (as we shall relate in 

 another chapter) in very interesting association 

 with the new metal radium. And we can find 

 out not only the constitution of our own sun, but 

 the constitution of alien suns millions of millions 

 of miles away — all told by the throbbing mole- 

 cules 1 Nor is this all ; it is possible by the 

 same means, through consideration of certain 

 details, to measure the velocity and masses of 

 double stars. Well may Sir Robert Ball ask : 

 " Could anything show more wonderfully how the 

 different branches of science have become inter- 

 woven than the fact, that by looking at a beam of 



