Parts of Water and of Depblogifticated Air. 339 
¥mell, which he could not divett it of by wafhing ; and that - 
the water in which the air was received had become flightly 
acid. I examined a portion of this water, which he was fo 
Kind as to fend me, and found by it that the whole of the re- 
ceiving water had contained the acid belonging to 2, drams = 
120 grains of nitre. I alfo examined the refiduum and the 
retort in which the diftillation had been performed, and found 
the refiduum highly alkaline, yet containing a minute quan- 
tity of phlogifticated nitrous acid. It had ated confiderably 
upon the retort, and had diflolved a part of it, which was dee 
pofited in the form of a brownifh powder, when the faline 
part was diflolved in water. ‘This earthy powder I have not 
yet thoroughly examined, but have no doubt that it princi- 
pally confifts of the earth of the retort. This experiment, 
and all others tried in earthen veflels, leave us ftill at a lofg 
to determine what becomes of the acid and phlogifton. They 
feem either to remain mixed with the air, in the form of an 
incoercible gas; or to unite with the alkali, or with the earth 
of the retort, in fome manner fo as not to be eafily feparated 
from them ; or elfe they are imbibed by the retorts themfelves, 
which are fufficiently porous to admit of fucha fuppofition. 
All that appears to be conclufrve from this experiment 15, that 
above one half of the weight of the nitre was obtained in the form 
of dephlogifticated air; and that the refiduum fill contained feme 
witrous acid united to phlogifion. 
7- Finding that the a&tion of the nitre on the retort tended 
to prevent any accurate examination of the produdts, I had re- 
courfe to combinations of the nitrous acid with earths from 
which the dephlogifticated air is obtained with lefs heat than 
from nitre itfelf. As thefe proceffes have been particularly de- 
eribed by Dr. PRiesTLey, by Mr. ScHEELE, and others, i 
You. LXXIV. Vy thall 
