In the present case, the water which appears in the well comes from a reservoir lying between the London clay and the greensand as its upper and lower envelopes. This reservoir is supplied by rain-water, which, percolating the London clay, sand, and chalk, and finding an impediment to its downward progress on reaching the greensand, flows into the space between the hard clay and greensand, as into a cistern. The process by which the reservoir is supplied is continuous, the water finding its way down to it as if by a series of small tubes, and pressing against the lower surface of the clay with a force which, if unresisted, would raise it to the level from which it descended. When the clay is pierced by the augur it is evident that this force is free to act, the resistance of the clay at the point where it is pierced being removed, and accordingly the water rises in the bore to the level from which it is supplied, and will continue to do so as long as the percolation lasts. The chief difficulty to be overcome was the great thickness of the substratum of chalk, which extends, probably, to a depth of about 1000 feet. The well, now completed, is a brick shaft 8¹⁄₂ feet in diameter, 247 feet deep, from whence an Artesian bore descends 328 feet, making the entire depth 575 feet. It is situated at the bottom of the Garden, near the Cricket Ground. An abundant supply of water having been brought to the foot of the hill from the well, and the supplies of a neighbouring water-company, it was necessary not only to raise it to the top, on a level with the building, but also to elevate it to a sufficient height for obtaining the requisite pressure for fountains to throw up water to heights varying from 5 to 280 feet. The following is a brief outline of the arrangements by which these objects are effected:-- Three reservoirs have been formed at different levels in the grounds, the lowest one being on the same level as the largest basins placed nearly at the base of the hill; the second or intermediate reservoir is higher up, and in a line with the basin in the central walk; whilst the third or upper reservoir stands on the top of the hill immediately adjoining the north end of the building. Next to the Artesian Well, an engine is placed which raises the water required to be permanently maintained in the reservoirs and in the basins of the fountains, and which supply or keep up the water that is lost by waste and evaporation.