Many persons prefer the taste of hard water to that of soft, and a change from one to the other, frequently causes a derangement of the digestive organs. The briskness, and rapidity of this and other water is owing to the air, and carbonic acid mixed with it. The air contained in water, has a larger proportion of oxygen than atmospheric air, and hence it is better adapted for the respiration of animals. The water procured from wells in the city of New-York, has gradually been growing more and more impure, as the city has increased in size, until a very large proportion of it, is entirely unfit for culinary and dietetic purposes. That in the lower part of the city, has always been, more or less, brackish, owing to the percolation of the salt water from the north and east rivers through the loose sandy soil, thus giving them a distinct saline impregnation. The amount of impurities contained in these waters, varies, therefore, in different parts of the city, according to its elevation, and the denseness of the population. A gallon of water from the well belonging to the Manhattan Company in Reade-street, yielded 125 grains of solid matter; while the same quantity of water, from their well in Bleecker-street, yielded 20 grains, and in 13th street, 14 grains. A gallon of water taken from four of the city wells in the densely populated parts of the city yielded on an average, 58 grains each of solid matter. The supply also of well water has been gradually diminishing in this city for the last several years. For example, at the Chemical Works on the North River, at 33d street, and at an extensive distillery on the East River, some distance above the Alms House, water cannot be procured in sufficient quantities on their premises, where, but a few years past, it was obtained in great abundance. At the Gas Works on the Collect grounds, where they have a well 20 feet in depth, by 18 feet in diameter, which, until 1834, furnished water freely, enabling the engine to raise 20,000 gallons in ten hours, in 1835 it required 14 to 16 hours to raise the same quantity, and in order to continue the supply, it was found necessary to return the water to the well, after using it for condensing the gas. The Corporation well, also, in 13th street, furnished, for several years, about 120,000 gallons of water daily, but in 1835, this quantity was reduced down to from five to ten thousand. In order to remedy this evil, a well was sunk at Jefferson Market, which in a short time deprived most of the wells in that vicinity, of water; thus drying up one source of supply, in order to increase that of another. There is, therefore, every probability that had not water been introduced into the city of New-York from abroad, the supply from the wells would, in a few years, have been insufficient for the economical, domestic and manufacturing purposes of the inhabitants. It is fearful to contemplate the amount of decomposing