Chemistry and Physics. 261 
apparently left any of its particles behind, nor had it admitted an 
atom of smoke into it; but it had drawn with it sufficient of the 
was considered 
eS uiner, ; 
te. To exhibit the air-rings, the column of smoke already described 
ln 80 as to ascend through the beam, and rather nearer the 
elamp. An air-ri 
pee what re. 
- te 1 of smoke may perhaps serve as a test for the exist- 
ngs in other cases, when, produced in air, they 
agri : 
