Читать книгу The Palace and Park - Edward Winslow Forbes - Страница 57

In July, 1852, the supply of water for the fountains and other great works in connexion with the Crystal Palace, first seriously engaged the attention of the Directors. Various proposals were made, and suggestions offered: some were at once rejected; others, although not free from difficulties, were taken into consideration. The most feasible of these was that which involved the extension to Sydenham of the pipes of one of the nearest London water-work companies—a measure that would at once secure a sufficient supply of tolerably good water. Against the proposition for sinking a well on the grounds, it was urged that the neighbourhood is almost destitute of water; that wells already excavated to the depth of two hundred feet had yielded but a small supply; and that even if a sufficient supply could be secured by digging, the water obtained could never be raised to the top of the hill.

Acting, however, upon sound advice, and after due consideration, the company commenced the sinking of an artesian well at the foot of the hill on which the Palace stands, and after proceeding to a depth of 250 feet, their efforts were rewarded.

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.

The reservoir on the summit of the hill contains the water required for the use of the building, and for the fountains throughout the grounds. Close to this reservoir is an engine-house, containing the steam-engines that raise part of the water into two large tanks erected on columns at the north end of the building close to the junction of the Sydenham and Dulwich roads. The columns, twenty-four in number, are of hollowed cast-iron, one foot in diameter. The central column, which is two feet in diameter, supporting a portion of the superincumbent weight, and making up the number, twenty-five, is the water-pipe, by which the tank is fed, and which forms also the conduit to the fountains in the building, and on the terraces. These two distinct actions of filling the tank and working the fountains proceed simultaneously through the same pipe. On the top of these columns are massive girders which support the plates, forming the bottom of the tank. The height from the stone curb of the reservoir to the bottom of the tank is 65 feet; the tanks are each 47 feet square by 15 feet deep, and capable of containing 207,000 gallons or about 900 tons of water. They supply also the water required in the building for the plants and kitchens, and charge the pipes provided against casualties from fire. The vast residue of the water in the great upper reservoir, in consequence of the sloping character of the ground, does not need any help from the engines, but flows direct to fountains on a lower level, and plays smaller jets. Through the same convenience, the waste water from the upper fountains is used a second time in the lower fountains.

The central or intermediate reservoir collects the waste water from the displays which take place on ordinary days, and which include all the fountains, save the two largest, and the cascades. Attached to this reservoir are also engines which pump the water back to the upper reservoir. The lowest reservoir collects similarly the waste water from the displays which take place in the two largest fountains on the days of great exhibition, and its engines return the water at once to the top level.