[ 363 ] 
principal ingredient, and, by its folution in the water, 
and its union with thefe earthy fubftances, from a 
a very rare volatile and elaftic body, is reduced to a 
fixed flate. 
This diffolving power of mephitic air may farther 
be proved from the recompofition of the pouhon 
water, by adding thereto the air expelled from it by 
codion. But as Mr. cavendish has already (hewn, 
that the abforbent earths of rathbone-place 
water may be rediffolved by the mephitic, or fixed 
air, which had been extracted from that water j and 
as Mr. lane has alfo demonftrated, that iron is 
rendered foluble in water, by the medium of me- 
phitic air, I therefore fhall not, at this time, detain 
the Soc ety with my experiments on the fame fub- 
jed ; but as thofe experiments contain fome phaeno- 
mena, that have not yet been noticed, I may, per- 
haps, offer them to the public on fome future oc- 
cafion. 
SCHOLIA. 
From the foregoing experiments, it appears that 
the mephitic air and martial earth, contained in 
the pouhon waters, ftrongly attrad each other, and, 
uniting together, form a concrete foluble in water, 
and readily diflinguifhed therein, by the peculiarly 
brifk acidulous tafte, which it receives from this 
aereal principle, joined to a rough fubaflringent tafte, 
which proceeds from the iron. This concrete, like 
other vitriols of iron, flrikes a black colour with 
galls, and may well be efteerned a faline body of the 
neutral kind, of which the mephitic air conftitutes 
A a a z the 
