+ 
A. A. Hayes on the Cochituate Water. 257 
Arr. XXIX.—On a remarkable change which has taken place 
in the composition and characters of the Water, supplied to 
the City of Boston, from Lake Cochituate; by Aueustus A, 
Hayes, M.D., Assayer to State of Massachusetts. 
(Read at a meeting of the American Academy, 11th January, 1855.) 
» Inthe study of the chemical composition of waters, used for 
domestic. purposes, a wide field is opened for inquiries of high 
Scientific interest, as the accurate comparisons of different waters, 
lead us throngh both departments of modern chemistry, the or- 
ganic and inorganic. ‘This interest is however secondary to the 
Importance of careful inquiries in an economical view, as we 
have actions of waters on substances with which they come 
mM contact, at one point modifying their composition so as to 
render them purer or less salubrions, and when a water passes 
Some distance, its characters may thus be made to differ at dif- 
ferent points. Not only is the water changed by contact with 
different bodies, with which it is brought in contact, but conduits 
- Masonry or iron are in special cases rapidly destroyed. 
Although my observations on the water supplied to this city 
Were among the earliest made before its introduction, they have 
been continued since that time, and within two years partial 
analyses have been made almost weekly, for the purpose of learn- 
Ing the cause of any changes occurring. The results thus ob- 
tied will be given in a future paper, with the conclusions are 
rived at, in a general form—while at present, it is my design to 
call attention to the condition of the water, as it has existed for 
about ten weeks, . : 
_ Cochituate water, derived mostly from surface drainage, as it 
18 found in the Pond or Lake, belongs to the class of peaty wa- 
ters, so common in New England. — It has not characters in com- 
mon with the green or colorless waters of limestone formations, 
hor the medium or mixed qualities of our river waters. In its 
Normal state, it may be considered as a pure water, holding in so- 
Pounds of these acids and bases, inciuding alumiva and oxyd of 
D Series, Vol, XIX, No. 56,—March, 1855. 
