C 1*5 1 



is rather lighter than common air, which favours the: 

 fuppofition of the fixed, or heavier part of the com- 

 mon air, having been precipitated. 



An animal will live nearly, if not quite as long, 

 in air in which candles have burned out> as in com- 

 mon air. This fael furprized me very greatly, having 

 imagined that what is called the confumption of air 

 by flame, or refbiration, to have been of the fame 

 nature 5 but I have iince found, that this fact has- 

 been obferved by many perfons, and even fo early 

 as by Mr. Boyle. I have alfo observed* that air in 

 which brimflone has burned, is not in the leaft in- 

 jurious to animals, after the fumes, which at firfi 

 make it very cloudy, have intircly fubfided. 



Having read,- in the Memoirs of the Society at 

 Turin, Vol.1, p. 41. that air in which candles had 

 burned out was perfectly reftored, fo that other 

 candles would burn in it again as well as ever, after 

 having been expofed to a considerable degree of 

 cold, and likewife after having been compreffed in 

 bladders (for the cold had been fuppofed to have 

 produced this effect by nothing but condenfation) : 

 I repeated thefe experiments, and did, indeed, find, 

 that, when I comprefled the air in bladders, as the 

 Count de Saluce, who made the obfervation, had' 

 done, the experiment fucceeded : but having had. 

 fufficient reafon to diftruft bladders, I compreffed. 

 the air in a glafs velTel (landing in. water j and then 

 I found, that this procefs is altogether ineffectual for 

 the purpoie. I kept the air compreffed much more,, 

 and much longer, than he had done, but without 

 producing any alteration in it. I alfo find, that a>. 

 greater degree of cold than that which he applied,. and; 



of 



