2~o Mr. Cavendish’s Experiments on the 
Except this, the only difference I know In the manner of 
conducting the experiment is, fir ft, that Mr. Gilpin ufually 
continued working the machine for half an hour at a time, 
whereas I feldom worked it more than ten minutes; and, fe- 
condiy, that in Mr. Gilpin’s Experiments the common air in 
the refervoir bore a lei s proportion to the dephlogifticated air 
than in mine ; in confequence of which it was necefiary for 
him frequently to introduce common air. On this account, 
the proportion of the two airs in the bent tube would be conli- 
derably different at different times; but on the whole, the 
common air ablorbed bore a greater proportion to the dephlo- 
gifticated than in mine. 
Though the whole quantity of air ablorbed in thefe ex*- 
periments is known with confiderable precifion, yet it is 
impoliible to determine, with any accuracy, how much of 
each kind was abforhed, on account of our uncertainty 
about the nature of the air which remained at the end of 
the experiment. But if in the laft experiment we fuppofe 
that the air abforhed Ipontaneoufly between the 15th and 
19th of March was intirely dephlogifticated, and that what 
remained. at the end of that time was of the purity of com- 
mon air, it will appear, that 4090 of dephlogifticated and 
2588 of common air, which is equivalent to 4480 of pure 
dephlogifticated air and 2198 of phlogifticated air, were ab- 
forbed at the time the electrification was flopped, and confe- 
quently the dephlogifticated air is. 4 of the phlogifticated 
air; whereas in my fir ft experiment it leemed to be and 
in my laft ... 
But the quantity of acid produced, and confequently, I fup- 
pofe, the faturation of the foap-lees, depends only on the quan- 
tity of phlogifticated air abforbed ; and the effeCt of the greater 
or lefs quantity of dephlogifticated air is only to make the 
nitre 
