[ 3 6 7 ] 
I ufed in the experiment, and that more mephitic' 
air might, perhaps, have been expelled from the 
water, had I only mixed with it the exaft quantity 
of this acid, that was required to diffolve the earthy- 
fubftances contained therein. 
Thirdly. Thefe faline concretes, contained in the 
pouhon water and other aridities , are fubjed to de- 
compofition, not only from acids, as before related,, 
but alfo from alcalies , whether fixed or volatile : all 
which more powerfully attract this fubtile aereal 
principle than it is attracted by the martial and ab~ 
lbrbent earths, to which it is united in thofe waters.. 
And here again appears anexad agreement between 
thefe aereo-faline concretes and various neutral falts,, 
in the mode of their decompofition. For the am- 
moniacal falts (which are all compofed of the volatile 
alcali, united to an acid fpirit, either muriatic, ni- 
trous, or of fome other kind) fo foon as one of the 
fixed alcalies, or quicklime, is added to any of them, 
the acid fpirit which it contains, quitting its union 
with the weaker volatile alcali , this laffc is let loofe ; 
aud the ftronger alcali , or quick-lime, takes its 
place; between which and the acid fpirit a new' 
combination is formed. The fame happens when 
any alcali , either fixed or volatile, is added to the 
acidities ; their elaftic fpirit then quits the ferrugi- 
nous and abforbent earths, to which it was joined, 
and forms a new combination with the alcali , by 
which it is more powerfully attracted than by thefe 
earthy fubflances. Thefe earths, therefore, being 
no longer ful'pended in the water by the aereal fol- 
vent, render it turbid and milky, until they have 
gradually fubfided therein, in the form of a white 
fedimenti 
