HUDSON AND MOHAWK DISTRICT. 267 



One pint gave 8 grs. solid matter, consisting of 



Chloride of sodium . I- 042 



Sulphate of lime 1"8I6 



Sulphate of magnesia 4'llG 



Carbonate of lime 0-C20 



7-594 

 Hydrosulphurtt of magnesium and organic matter, • 406 



8-000 



The quantity of gas remains undetermined, and it is assumed that the combination is as I 

 have here stated. A small quantity of sulphur is deposited upon the stones and other 

 substances over which the water tiows. 



The large bodies of water which are collected in reservoirs formed in the rocks belonging 

 to the Champlain division, are generally soft, and quite free from mineral and organic 

 matter. We have an illustration of this fact in the water of Lake Champlain. It gives 

 only a faint cloud with nitrate of silver, and scarcelj" a perceptible precipitate with chloride 

 of barium ; hence there is almost a total absence of the chlorides and sulphates, bodies 

 which most usually exist in hard or mineral waters. This is accounted for by the purity of 

 the waters which supply the lake. Most of the rivers and streams rise either in the Primary 

 region, or in the hard shales of the Piimary and Taconic system of Vermont. The drains 

 from the Tertiary clay upon its border scarcely affect the great mass of the water forming 

 the body of the lake. 



34* 



V 



