i6i Analyjh of the Air. 
great, then I made ufe of large chymical recei- 
vers inftead of the glafs a y ; But if thefc 
quantities were very fmall, then inftead of the 
boirhead and deep cylindrical glafs ^ 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 \^ater 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 ; I meafured the bulk of the fpaces 
z^y Qi 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, I firft placed a high ftand, or 
pedeftal in the veft'el full of water x x^i 
(Fig. 35.) which pedeftal reached a little 
higher than On this pedeftal I placed 
the candle, or living animal , and then 
whelmed over it the large inverted glafs 
which 
