‘ 
‘130 Mr. Cavenpisu’s Experiments.on Air. 
a mixture of inflammable and dephlogifticated air, by thutting 
the cock, faftening a bent glafs tube to its mouth, ‘and letting 
up the end of it into a glats jar inverted into water, and con- 
taining a mixture of 19500 grain meatures of dephlogitticated 
air, and 37000 of inflammable;. fo that, upon opening the 
cock, fome of this mixed air rufhed through the bent tube, and 
filled the globe *. ‘The cock was then ihut, and the included 
air fired by ele&tricity, by which means almoft all of it loft its 
elafticity. The cock was then again opened, fo as to let in 
more of the fame air, to fupply the place of that deftroyed by 
the explofion, which was again fired, and the operation conti- 
nued till almoft the whole of the mixture was let into the 
globe and exploded. By this means, though the globe held 
not more than the fixth part of the mixture, almoft the whole 
of it was exploded therein, without any frefh exhauftion of 
the globe. ) 
As I was defirous to try the quantity and teft of this burnt 
air, without letting any water into the globe, which would 
have prevented my examining the nature of the condenfed 
matter, I took a larger globe, furnifhed alfo with a ftop cock, 
exhaufted it by an air-pump, and ferewed it on upon the cock 
of the former globe; upon which, by opening both cocks, the 
air rufhed out of the {maller globe into the larger, till it be- 
came of equal denfity im both; then, by fhutting the cock of 
the larger globe, unfcrewing it again from the former, and 
opening it under water, I was enabled to find the quantity of 
the burnt air in it; and confequently,, as the proportion 
which the contents of the two globes bore to each other was 
* In order to prevent any water from getting into this tube, while dipped 
under water to let it up into the glafs jar, a bit of wax was was ftuck upon the 
end of it, which was rubbed off when raifed above the furface of the water. 
_ known, 
