234

MODERN STEAM PRACTICE.

sion of the sewage from the pumps' to the reservoir, and the lowereight for its discharge into the river. These apertures are all openedand closed by pen Stocks.

The reservoir, which is 6^ acres in extent, is covered by brickarches, supported on brick piers, and is furnished with weirs foroverflows, and with a flushing culvert. The height, level, andgeneral construction are similar to the one at Barking Creek. Overthe reservoir are built twenty-one cottages, for the engineers andother persons employed upon the works.

The ground upon which these works are constructed consists ofpeat, sand, or soft silty clay, and affords an insufficient foundationwithin 25 feet of the surface. To obviate the need of removing thisvast mass of soil, and thereby reduce the expense of the foundations,trenches were cut down to the solid earth, and the culverts on thevarious levels were built as far as practicable in the same trenches,one above the other; the lowest, leading from the Outfall Sewer tothe pump wells, support those discharging the sewage from thereservoir, and these again support those leading from the pumpsinto the reservoir. On account of the pump wells it was necessarythat the walls of the engine house should be carried down to thedepth of the gravel, independently of the nature of the ground; butsuch was not the case with the boiler house. The boilers and stoke-hole floor are supported on arches springing from walls built upfrom the gravel, and the space below the floor is made available asa reservoir for Condensed water. The water from the hot and coldwells of the engines is conveyed hither, one compartment beingused as a chamber for cooling that from the hot well, previous toits being used again for condensing water. With the same objectof saving separate foundations, coal Stores and workshops have beenerected partly on the external walls of the reservoir and partly onthe culverts in front of them; large coal Stores being also providedin front of the boiler house and on a level with the stoke holes, intowhich the coals are brought on tramways. There is also a tramwayfor the upper-level coal sheds, on the level of the tops of the boilers,from whence the coals are shot into the stoke holes below. Tram-ways are also laid from the coal sheds to the river, where jetties arebuilt for landing the coals. A wall has been constructed along theriver frontage of the works for a distance of about 1200 feet, bywhich a large portion of the “Saltings” has been reclaimed. Thiswall is of brick, carried upon brick arches resting on piers forrned