Mr . G A ve n d i sifts Experiments on Air. 38 1 
in the latter from tnrbith mineral. In the firft experiment, the 
quantity of foap-lees u fed was 35 meafures, each of which was 
equal in bulk to one grain of quickfilver ;■ and that of the air 
abforbed was 416 fuch meafures of phlogifticated air, and 914 
of dephlogiftieated. In the feeond' experiment,. 178 meafures - 
of foap-lees were ufed, and they abforbed 1 1920. of phlogifti- 
cated air,, and 4860. of dephlogiftieated. It muff be obferved, • 
however, that in both- experiments- fome. air remained in the 
tube uncondenfed, . wh©fe ; degree of purity I had no way of 
trying; fo that the proportion of each.fpecies of air abforbed is 
not known with much exaclneis. . 
As far as the experiments- hitherto- p.ublifhed •> extend,, w©- 
fcarcely know more of the nature of the phlogifficated part of 
our atmofphere., thanuhat it is not diminifhed by lime-water,, 
cauftic alkalies, or nitrous air.; thafit ia-unfk to fwpport fire,, 
or maintain life- in animals ;' and that its fpecifc gravity is- 
not much lefs than that of common air : fo that, though the 
nitrous acid, by being united to phlogifton, is converted into 
air poftefted of thefe properties, and confequentlv, though it 
was reafonable to * fuppofe, that part at leaf of the phlogift-i- 
cated air of the atmofphere confifts -of this acid united to phlo-- 
gifton. yet it might fairly be doubted whether- the whole is of 
this kind, or whether there are not in reality many, different 
fiibftances confounded together by us under the name of phlo- 
gifticated air. f therefore made an experiment to determine, 
whether the whole of a^givens portion of the phlogifficated air 
of the atmofphere. could be reduced to nitrous -acid, or whether 
there was not a part of a different nature from the reft, which, 
would refufe to undergo that change. The foregoing experi- 
ments indeed in fome meafure decided this point, as much the 
greateft. part of. the air. let] up into the tube loft its elafticity ; 
