CROTON AQUEDUCT. Carb. Lime and Magnes., 1 25 Extractive Matter and Loss, 75

Total, 7

No. 3. A pint yielded 4 50 grains composed of Mur. Soda, 1 Mur. Magnes., - 2 Carb. Lime, 1 Sulph. Lime and Extractive, 50 - -

Total, 4 50

No. 4. A pint yielded about 4 grains composed of Mur. Lime. Mag. and Extractive, 1 80 Mur. Soda, - - Sulph. Lime, Carb. Lime, - - 1

Total, 4 05

No. 5. Contained Sulph. and Mur. Lime, with a little coloring matter. No. 6. Contained Sulph. Lime, Sulph. and Mur. Soda, with Extractive. No. 7. Was not disturbed by Nitrate of Silver, Sulph. Silver, Ammonia, nor Barytic Salts.

From whence, then, are derived those foreign ingredients ? It has been already stated, that thesand bed of this island may be regarded as a filter or sponge, which, under ordinary circumstances is saturated with fresh water from the atmosphere. If this spongy mass was originally free itself from any mineral impregnations, and its surface always open, the watei would of course remain pure for any definite period. When this filter itself contains foreign ingredients, and the free transmission of pure water is prevented, its quality must be impaired. From accurate data, these obstacles to the transmission of water from the surface, by dwellings and pavements, are estimated to carry off into the river nearly one half of the water which falls from the atmosphere. In the neighborhood of large open squares, it is consequently observed that the wells are more pure, but they must sooner or later partake of the same deterioration. The water in the immediate vicinity of the park, although very impure, is nevertheless of a better kind than that from more distant wells and we have been informed that the well ;