STATIONARY ENGINES. 235

of iron Caissons filled with concrete, which are carried down to thegravel.

The chimney into which the flues from the boilers are conveyedis square in plan externally, 8 feet 3 inches in internal diameterthroughout, and 200 feet high; it is founded upon a wide bed ofconcrete brought up from the gravel, which is here 26 feet belowthe surface. The reservoir, the several culverts, and the pump wellsare connected by flues with the furnaces of the boilers, for the pur-pose of Ventilation, in the same way as at the Deptford and otherpumping stations.

The outlet into the river from the Outfall Sewer of these worksconsists of twelve iron pipes, each 4 feet 4 inches in diameter, car-ried under the “Saltings” into a paved channel formed in the bedof the river. These pipes are connected with the Outfall Sewer byculverts in brickwork on the land side of the wall, the numbers ofthese culverts being gradually reduced and their dimensions in-creased as they approach the junction with the large sewer.

HIGH-PRESSURE GEARED PUMPING ENGINES.

Small high-pressure geared engines maybe conveniently used forpumping water out of docks, and for other drainage purposes, beingarranged for three pumps. The connecting rod runs from the cross-head of the piston rod, and works a cranked shaft, having a fly wheelat one side and pinion at the other, geared into a spur wheel keyedon a cranked shaft for the middle pump; one of the side pumpsis worked from a pin let into one of the arms of the spur wheel, andthe other pump is driven from a crank placed on the other end ofthe shaft. The engine is placed horizontally, and the pumps arevertically arranged against the side of the dock wall. When theyare needed to pump the water out of a dock in course of construc-tion, the engine is bedded on an overhanging wooden frame, havinga strut let into the wall, or temporary pile foundation, on each sideof the frame for carrying the engine and the three throw cranks forthe pumps. The pumps are in some instances of the plunger type,having the plungers cast in brass; while others are simply lift pumps,fitted with valves of india rubber working on brass gratings. Thereis one suction pipe and one discharge pipe common to all the threepumps; the former has a three-branched pipe fitted to the top, towhich are bolted the pumps, one to each branch; while the latter is