is recollected that the hardest spring water seldom contains so much as one thousandth part of its weight of any foreign body in solution, it would seem that the term, mineral water, would be a more correct designation for the ordinary waters of this city. Results of analysis of various mineral and pump waters in the city of New- York, by George Chilton, chemist : No. 1. A pint of water yielded 10 grains of solid matter, consisting of Mur. Magnes. - " - 3 50 Mur. Sod. - 4 Sulph. Lime, - 0 25 Carb. Lime and Magnesia, 1 25 Carb. Potass and Extractive, - 0 75 Loss, - 0 25 Total, 10 No. 2. A pint yielded 7 grains of dry residue, consisting of Mur. Magnes. - 2 Mur. Soda, - 2 Sulph. Lime, - - ... l 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, - - 0 50 Total, 4 50 No. 4. A pint yielded about 4 grains composed of Mur. Lime. Mag. and Extractive, 1 80 Mur. Soda, - - 1 Sulph. Lime, - 0 25 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 the sand 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 of the Manhattan Company is mostly supplied from that quarter. It has been observed, also, that the vicinity of grave yards communicates a ropy appearance to the water ; and the water from such wells, becomes, in warm weather, very offensive in the course of a few hours. If the above facts be well founded, we must naturally anticipate a deteriora- tion of our waters, proceeding pari passu, with the increase of the city ; and we accord- ingly find this to be the case. Until within the last few years, the water on the elevated ground in Broadway, was considered to be the best in the city. In the progress of im- provement, this water is now hard and unpalatable. Indeed, we know of families living above Broome-street, in Broadway, who are now supplied throughout the year by watew carts from the country ; and in the direction of Laurens-street, we have been informed that 28 MEMOIR OF THE this foreign supply is required still farther to the north of Broome-street. But we are now to allude to another cause, which must greatly impair the purity of our waters : — Into the sand bank, underlying the city, are daily deposited quantities of excrementitious matter, which, were it not susceptible of demonstration, would appear almost incredible. With our present population, there is put into this sand about 100 tons of excrement every 24 hours. In these deposites we may find all the ingredients detected by analysis, and which destroy the purity of our waters. But in this estimate we do not include an equal amount of urine, for the following reason : This liquid, when stale or putrid, has the remarkable property of precipitating the earthy salts from their solution, or in other words, it makes hard waters soft. Although the fastidious may revolt from the use of water thus sweetened to our palate, it is perhaps fortunate that this mixture is daily taking place, for otherwise the water of this city would become, in a much shorter space of time than it actually does, utterly unfit for domestic purposes. We cannot take