50 On the Analysis of 
lime water; this is usually occasioned by the 
water holding swperearbonate of lime in so- 
lution; the addition of lime water reduces 
the supercarbonate to carbonate, which is 
insoluble and falls down in the state of a white 
eranular powder. When a spring contains 
nothing but supercarbonate of lime, which is 
the case with the water of an excellent pump 
in this neighbourhood,* lime water is the only 
test wanted to ascertain the proportion of salt 
in it. Leta given portion of the spring wa- 
ter be saturated by lime water, adding it as 
long as milkiness ensues; the carbonate of 
lime is precipitated and may be determined 
by the usual: means. I find it however rather 
preferable to adda small excess of lime water 
tosecure the precipitation of the whole acid; 
when the salt has subsided, the clear liquid 
may ‘be poured off and tested by an acid, and 
the salt may be dissolved -by test muriatic or 
nitric acids. Thus the whole quantity of 
lime will be found, from which, deducting 
that added in lime water, there will remain 
the lime in the spring water originally com- 
bined with carbonic acid. Inthis way Lfind 
the -supercarbonate of lime in 5 .0z. of the 
water abovementioned, to consist of 
* George-street. 
