ON t)EW, &c. 217 



founded upon this experiment as without force, 

 I shall now offer several considerations, which 

 seem to prove, that air is actually heated by the 

 sunbeams, which enter it. 



1 . Air both reflects and refracts light, and all 

 other bodies, as far as I know, acquire heat, 

 while they act thus on the light of the sun. 



2. Air suffocates or absorbs the sun's light, 

 which it cannot be supposed to do, without in- 

 creasing in temperature. 



3. If air, considered as an uniform fluid, 

 were even incapable of gaming heat directly 

 from the sun's rays, heat would be communi- 

 cated by them to it, through the intervention 

 of the innumerable particles of solid matter, 

 which the trivial experiment of receiving a sun- 

 beam into a darkened room shows to be present 

 in the atmosphere. Should it be said, that this 

 appearance may occur only in the neighbour- 

 hood of the earth, from the accidental admix- 

 ture of solid matter raised from its surface by 

 winds, or in any. other way, the answer is, that, 

 as my inquiry is concerning the existence of a 

 certain condition of the atmosphere, it matters 

 not how this originates. Nothing more can be 

 demanded, than that it should always be found, 

 which I believe to be the case ; since, if I can 

 trust my memory with respect to what took 

 place many years ago, I should say, that such 



