Spring and Mineral Waters. 61 
excess of acid. Hence the furring of pans 
and tea-kettles with this kind water. By boil- 
ing the water is of course rendered much 
softer than before. It may then be used for 
washing, scarcely curdling soap; but it still 
contains about + of the earthy salt and gives 
milkiness with acetate of lead. If a water 
contain only sulphate of lime, boiling does 
not, I apprehend, soften it at all. 
When spring water is used by manufactur- 
ers for washing, &c. it isadvantageous to have | 
it some time exposed to the atmosphere, in a 
reservoir with a large surface. This exposi- 
tion suffers the carbonic acid in part to escape, 
and the carbonate of lime to precipitate ; and 
in some degree supersedes the necessity of 
boiling the water. ‘The more any spring is 
drawn from, the softer the water becomes, it 
should seem. I have this morning examined 
a spring which yields many thousand gallons 
every day. The water is comparatively soft; 
it does not curdle scarcely at all with soap: it 
is very nearly as soft as the before mentioned 
pump water boiled.. The hardness in it arises 
from a little sulphate of lime and a little 
carbonate. 
One of the most striking facts I have ob- 
served is, that all spring water containing 
carbonate or supercarbonate of lime, is essen- 
