161 Analyfis of the Air. 



great, then I made ufe of large chymical recei- 

 vers inftead of the glafs a y : But if thefe 

 quantities were very fmall, then inftead of the 

 bolthead and deep cylindrical glafs a y, I 

 made ufe of a fmall cylindrical glafs, or a 

 common beer glafs inverted, and placed 

 under it a Viol or Jelly glafs, taking care 

 that the water did not come at the ingredi- 

 ents in them, which was eafily prevented 

 by drawing the water up under the inverted 

 glafs to what height I pleafed by means of 

 a fyphon 5 I meafured the bulk of the fpaces 

 zy or z n, by pouring in a known quan- 

 tity of water, as in the foregoing Experi- 

 ment, and making an allowance for the 

 bulk of the neck of the bolthead, within 

 the fpace z }'. 



When I would take an eftimate of the 

 quantity of Air abforbed and fix'd, or ge- 

 nerated by a burning candle, burning brim- 

 ftone or nitre, or by the breath of a living 

 animal, <&c. I firft placed a high ftand, or 

 pedeftal in the vefTel full of water x x i 

 (Fig, 35.) which pedeftal reached a little 

 higher than z z. On this pedeftal I placed 

 the candle, or living animal , and then 

 whelmed over it the large inverted glafs zzaa, 



which 



