6 Mr. CXven dish’s Experiments on Air. 
air fhould' be -of, in order to be dimitiifhed mod: readily, and ; to 
the greateft degree; and 1 found, that, when good dephlogifti- 
cated air iv as- ufed, the diminution was but fmall ; wherr per- 
fedtJy phlogifticated air was ufed, no fenftble diminution took 
place; but when five parts of pure dephlogifticated air were 
mixed with three parts of common air, almoft the whole of : 
the air was made- to difappear. 
It mu Pc be- confidered, that common air con fiffs of one part- 
of dephlogifticated air, mixed with four of phlogifvieated ; fo 
that a mixture of five parts of pure dephlogifticated air, and 
three of common- air, is the fame thing as. a mixture of feven * 
parts of dephlogifticated air with three of phlogifticated. 
Having made thefe previous trials, I introduced into the tube- 
a little foap-lees, and J then letup feme dephlogifticated and 
common air, mixed in the above-mentioned proportions-,, which 
riling to the top of the tube M, divided the foap-lees into its * 
two legs. As faff as the- ak was diminifhed by the eleffric 
fpark, I continued adding more of the - fame kind, till no fur- - 
ther diminution -took place-: after which a little pure dephlo- 
gifticated air,., and after that - a little common ak, were added, 
in order to fee whether the cenation of diminution was not - 
owing to fome imperfeftion in the proportion^ of the two kinds 
of air to each other*; but without effects The foap-lees being 
then poured out of the tube, and depurated from* the quick--- 
* From what follows it appears, that, the reafon why the air ceafed to diminilh . 
was, that as the foap-lees were then become neutralized, no alkali remained to ab-- 
forb the acid formed b-y the operation, and in confequence fcaree-any air was turned 
into acid. The fpark, however, was not continued long enough after the appa- 
rent celfapon. of diminution, to determine, with certainty, whether -it. was only 
that the diminution went on remarkably flower than before, or that it was almoi.1 
come to a fland, and could not have been carried .much, further, though I had 
jiterfiftedJn palling the fpark s. 
filver, , 
