40 FRAGMENTS OF SCIENCE 



ultimate extinction. Every star is seen across the entan- 

 glement of wave-motions produced by all other stars. It 

 is the ceaseless thrill caused by those distant orbs collec- 

 tively in the ether that constitutes what we call the "tem- 

 perature of space." As the air of a room accommodates 

 itself to the requirements of an orchestra, transmitting each 

 vibration of every pipe and string, so does the interstellar 

 ether accommodate itself to the requirements of light and 

 heat. Its waves mingle in space without disorder, each 

 being endowed with an individuality as indestructible as 

 if it alone had disturbed the universal repose. 



All vagueness with regard to the use of the terms 

 "radiation" and "absorption" will now disappear. Kadi- 

 ation is the communication of vibratory motion to the 

 ether; and when a body is said to be chilled by radia- 

 tion, as for example the grass of a meadow on a starlight 

 night, the meaning is, that the molecules of the grass have 

 lost a portion of their motion, by imparting it to the me- 

 dium in which they vibrate. On the other hand, the waves 

 of ether may so strike against the molecules of a body ex- 

 posed to their action as to yield up their motion to the 

 latter; and in this transfer of the motion from the ether 

 to the molecules consists the absorption of radiant heat. 

 All the phenomena of heat are in this way reducible to 

 interchanges of motion ; and it is purely as the recipients 

 or the donors of this motion that we ourselves become 

 conscious of the action of heat and cold. 



8. The Atomic Theory in reference to the Ether 



The word "atoms" has been more than once employed 

 in this discourse. Chemists have taught us that all matter 

 is reducible to certain elementary forms to which they give 



