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Analyfo of the Air. i $ 7 



rations, into the nature of a fluid, too fine 

 to be the object of our fight, muft be by 

 finding out fome means to cftimatc what 

 influence the ufuai methods of analysing 

 the animal, vegetable and mineral kingdoms, 

 has on that motile fluid 5 and this I effected 

 by affixing to retorts and bolthcads hydro- 

 ftarical gages in the following manner, viz. 

 In order to make an cftimatc of the quan- 

 tity of Air, which arofe from any body by 

 diitillation or fufion, I firft put the matter 

 which I intended to diftill into the fmali re- 

 tort r (Fig. 33.) and then at *z cemented 

 fad to it the glafs vcflcl a b, which was very 

 capacious at b 7 with a hole in the bottom.' 

 I bound bladder over the cement which was 

 made of tobacco-pipe clay and bean flower, 

 well mixed with fome hair, tying over all 

 four fmall flicks, which ferved as fplinters 

 to flrcngthen the joynt ; fometimes, inftead 

 of the glafs veflel a b, I made ufe of a large 

 bolthead, which had a round hole cut, with 

 a red hot iron ring at the bottom of it ;• 

 through which hole was put one leg of an 

 inverted fyphon, which reached up as far 

 as z. Matters being thus prepared, holding 



the retort uppermoft, I immerfed the bolt- 

 head 





