6 Experiments made upon 
a solution of fixed alkali, in its common caustic or carbonated 
state, is added to the water, a cloudiness is produced, and there 
is a gradual deposition of earthy matter, which on examination 
proves to be calcareous. The water in consequence of such 
treatment becomes soft, does not decompose soap, and may be 
used fur washing and other domestic purposes. 
5. If the water is boiled, and the boiling continued for fifteen 
or twenty minutes, a quantity of air is disengaged, which renders 
limewater milky, and there is a deposition of earthy matter, which 
exhibits all the characters of carbonate of lime. After this treat- 
ment the water becomes soft, and may be employed for washing 
and other culinary purposes: limewater is now incapable of im- 
pairng its transparency, and it is scarcely affected by the pure 
or carbonated alkalies. Hence, it seems, the carbonic acid gas 
and carbonate of lime contained in the water may be separated 
by continued boiling. 
6. The water when treated with nitrate of silver becomes 
cloudy, indicating the presence of a portion of common salt. 
Pure ammonia added to the water separates a very minute 
quantity of earthy matter, and indicates a little magnesian salt, 
which is probably the muriate. Nitrate of barytes produces a 
very slight effect, and shows a trace of alkaline or earthy sul- 
phate. Neither prussiate of potash nor solution of oak bark oc- 
.casions any change in the water after several hours ; from whence 
the absence of iron in it may be inferred. 
From the foregoing statements, which are founded upon ex- 
periments carefully made and repeated, I venture to conclude, 
that the Black Rock water contains an excess of carbonic acid 
gas, which holds in solution a portion of carbonate of lime. This 
earthy salt gives to the water its peculiar characters, and espe- 
cially its hardness, which is its distinguishing quality. The wa- 
ter certainly contains other foreign ingredients, such as muriate 
of soda, and a little magnesian salt ; but these substances (com- 
mon to almost every water) are scarcely worthy of notice, be- 
cause they exist in quantities toa small to be sensible to the 
taste, or to produce any medicinal effect. From some compa- 
rative experiments I have recently made upon the pipe-water 
commonly drunk in Cork, and the Black Rock water, there seems 
to bea great similarity, not only in the foreign ingredients com- 
mon to both, but also in the actual quantities they contain; with 
the exception of the carbonic gas and carbonate of lime peculiar 
to the Black Rock water. And if the pipe-water were impreg- 
nated with an excess of carbonic gas and a portion of limewater, 
an artificial water would be formed similar to the natural water 
at Black Rock. - 
The preceding experiments seem to lead to two simple modes 
of 
