Chav. VIII.
BRITAIN.
549
rancous tunnel ; at Islington its width is about 14 feet 6 inches, and its average depth4 feet 6 inches. Two hundred bridges were constructed in its varied course for the con-venience of the proprietors of the adjoining lands. The supply from the Hertfordshire springs being found inadequate to the demand of the company, a considerable addition wasobtained from the river Lea, on the banks of which is a sluice; and in order that theguardians may know what quantity to let out, a guage is fixed across it, composed of alarge stone, under which the water flows out in a regular manner.
The first distribution of water, as we have seen, was by leaden pipes, which abundantly sup-plied the conduits in various parts of the city; these were mostly destroyed during thegreat fire; from them the inhabitants received their several quantities by the aid of water-carriers. After the destruction of this system, a new arrangement was made to lay the wateron to the houses, and this was admirably accomplished by wooden pipes or mains, of elmtimber, and at the end of the last century, when they were removed to make way for iron,the New Itiver Company had upwards of 400 miles of wooden pipe.
When water-closets were more generally introduced at the commencement of the presentcentury, a more abundant supply of water was required, which was first poured into thecistern, usually placed in the basement, from whence by means of force-pumps it was throwninto the tank to feed the closet; this system was afterwards further improved by supplyingwater at a higher pressure by the use of steam-power, and which could be more easilyeffected through the introduction of iron pipes. Twenty miles per annum of wooden pipes,6 or 7 inches bore, with their 3-inch service pipes, were annually removed until the wholeof the districts supplied by this company were furnished with cast-iron mains; these varyin diameter from 1 to 3 feet, and the services are generally 4 inches.
When the iron mains were first laid down, they were supposed to impart a chalybeatequality to the water, and they were in consequence dressed in the interior with a pre-paration of lime-water, which entirely removed the evil. They were screwed together atthe joints, which prevented their free expansion and contraction, and often occasioned themto he broken by the varied temperature of the water, rendering them very defective in thewinter season. Cylindrical socket joints were then introduced, anti the pipes cast in lengths of9 feet, which entirely obviated all inconvenience. These joints being accurately turned ina lathe no stuffing is required; a little whiting and tallow is used, and they are at onceformed and the pipes driven up ; joints so made answer well to a suction pipe of a steam-engine 30 inches in diameter.
The tenant’s communication pipes are united to the mains by flange joints, which arecast with the pipes, and all the cross branches are slightly curved, which materially reducesthe friction to which they were subject when lying at an angle. Screw cocks have alsotaken the place of the valve-cock, so that the water is now gradually shut off, and not asformerly in an instant, which frequently occasioned the bursting of the pipes. At the NewRiver head, Pcntonville, there are two powerful steam-engines as well as an engine forforcing the water to a higher reservoir near the works, and another near TottenhamCourt Road.
The works are about 85 feet above the level of the Thames, and all the houses abovethis were formerly supplied by a windmill, afterwards by a horse-mill, then by a fire-engine,and in 1820 by three steam-engines of 63 horse power. Mr. Mylne, the engineer to thecompany stated, in the year 1844, when he gave his evidence to the Commissioners ofInquiry into the State of Large Towns, that the average annual quantity of water suppliedfor the last three years had been 614,087,768 cubic feet: deducting from this the largerconsumers, and street watering, amounting to about 33,529,400 cubic feet, there wouldremain 580.558,368 cubic feet per annum, equal to 46.^ cubic feet per tenement each alter-nate day ; the number of tenements supplied being 81,555.
Chelsea Water-works were established in the year 1724 : about two years afterwards thebasin in the Green Park was built for the supply of Whitehall, and another for Westminsterin Hyde Park. The water was at first obtained from the Thames by means of a wheelthrowing it into settling ponds, which was worked from other ponds in the same manneras a tide mill, and in the middle of the last century 1700 tons of water were so raiseddaily, which not being adequate to the increasing demand, the works were enlarged, andabout the year 1810, they were removed from the site which now forms the Belgrave basinto their present situation. They occupy nearly 7 acres of land ; t !, e water was originallyobtained from a dolphin, which stood about 50 feet from the bank ; this was a brickstructure below, and iron above, into which the mains entered, and drew their supply ; hutbeing situated near the mouth of a large sewer, it was removed, and the main pipes arenow supplied from the Surrey side of the river ; the water is received into settling reser-voirs, lined with stone and brick, the first of which is ICO feet in length, 70 feet in width,and 10 feet in depth; from thence it is forced up into one 300 feet in length, 160 inbreadth, beyond which is another, 540 by 140 feet; from these the water flows intotwo filters constructed below them, one of which is 210 by 180 feet, and the other 351 by180 feet.
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