Jnalyfis of the Air. 1 6 9 



drawing the water up under the inverted 

 glafs to what height I pleafed by means of 

 a fyphon : I meafured the bulk of the fpaces 

 z y or z ;;, 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 (pace z y. 



When I would take an eftimate of the 

 quantity of Air abforbed and fixed, or ge- 

 nerated by a burning candle, burning brini- 

 flone or nitre, or by the breath of a living 

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

 pedeftal in the veffcl full of water x x 

 (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 

 z z a a y which was fufpended by a cord, 

 fo as to have its mouth r r three or four 

 inches under water 5 then with a fyphon I 

 fucked the Air out of the glafs veffel, till the 

 water rofe to z z. But when any noxious 

 thing, as burning brimftone, aquafortis, or 

 the like, were placed under the glafs ; then 

 by affixing to the fyphon the nofe of a large 

 pair of bellows, whofe wide fucking orifice 

 s clofed up, as the bellows were inlarged, 



they 



