174 PROCEEDINGS OF THE AMERICAN ACADEMY 



" Although my observations on the water supplied to this city were 

 among the earliest made before its introduction, they have been con- 

 tinued since, and within two years partial analyses have been made 

 almost weekly for the purpose of learning the cause of any changes 

 occurring. The results thus obtained will be given in a future paper, 

 and the conclusions arrived at in a general form, while at present it 

 is my intention 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 is 

 found in the pond, or lake, belongs to the class of peaty waters so 

 common in New England. It has not characters in common with 

 the green or colorless waters of limestone formations, nor the medium 

 or mixed qualities of our river waters. 



" In its normal state, it may be considered as a pure water, holding 

 in solution four or five grains of mineral salts in one United States 

 standard gallon ; and these consist of compounds of chlorine with 

 sodium, potassium, calcium, and magnesium. Carbonates and sili- 

 cates of these bases exist, in varying proportions, at different seasons. 



" Its organic constituents, including the gases dissolved, are those 

 of the most importance, as these give it particular characters, modify- 

 ing its chemical relations, and affecting the taste, color, and purity of 

 the fluid. In the spring and autumnal seasons there are found ulmic, 

 humic, crenic, and apocrenic acids, and sparingly soluble compounds 

 of these acids and bases, including alumina and oxide of iron. With 

 these is a neutral body, which resembles mucilage from gum, and is 

 usually in a changing state, especially while the water is warm in 

 the summer season. The gases dissolved are oxygen, nitrogen, and 

 carbonic acid ; the nitrogen never has the volume relation to the oxy- 

 gen which exists in air, being, except in rare instances, in smaller 

 proportion, and instances have occurred when the nitrogen was no more 

 4han twenty volumes to eighty of the oxygen. The volume of car- 

 bonic acid also varies ; while about one volume of all the gases exists 

 in thirty-six of normal water. There are present also numerous ani- 

 malcules and infusoria, fresh-water sponges, and abundance of ochrey 

 matter, resulting from the chemical action of the water on the iron 

 pipes. The animalcules indicate a state, which really exists, of a 

 disturbed balance between the fish, the Crustacea, animalcules, and 

 subaqueous vegetation of the lake. Although throughout the year 

 the water, at times increased by rains and melting snow, cannot be 



