717 



rolls down between the mar-lie? on each side 

 of the river to far belo\v Gravesend. 



On the north side of the Thames the inter- 

 cepting sewers are divided, as we have 

 into three distinct lines, two of "which, called 

 respectively the high and middle level sewers, 

 unite at and pass over the River Lea ; and the 

 third, the low level, after passing through 

 the Thames Embankment, will eventually jui:i 

 them at the proposed pumping station at Abbey 

 Mills. Three parallel sewers, called the north- 

 ern ontfall sewer, each 9 feet by 9 feet, are con- 

 structed as one work, in a concrete embank- 

 ment, and are carried by aqueducts over rivers, 

 roads, and railways, to the Barking reservoir. 



On the south side of the Tiames there are 

 three lines of intercepting sewers, which are 

 also known as the high level, the middle level, 

 and the low level, and these converge to one 

 point at Deptford pumping station, where the 

 sewage from the low level is lifted into the 

 upper-level sewers, and their united stream 

 Hows thence deep under Greenwich and 

 Woolwich, through one outfall sewer, 11-J feet 

 in diameter, to the Crossness reservoir and 

 pumping station in Erith Marshes. Three- 

 fourths of London north of the Thames are, 

 however, elevated so far above the river that 

 the sewage can be conveyed by its own gravi- 

 tation to the level of high Avater at Barking, 

 and this is why the sewers are carried in an 

 embankment at such a height above the level 

 of the marches, and no pumping station is 

 needed at the outfall. But on the south side 

 the levels are so low that this cannot be done, 

 and therefore the outfall sewer is under ground, 

 and a pumping station is placed at its outlet to 

 raise the sewage into the reservoir. 



The high, middle level, and outfall sewers 

 on both sides of the Thames are now, with the 

 exception of a few very minor connections 

 and Avork?, completed, the low-level sewer 

 on the south side Avill be finished this year, but 

 the short pieces of the northern low-level 

 sewer cannot be completed until the Thames 

 Embankment is finished. About one-third of 

 the metropolitan sewage is now intercepted 

 and discharged at the outfalls, and there can be 

 little doubt that but for this th river would 

 have been much more offensive this dry season 

 than it has yet been. 



The areas drained by the three levels on the 

 north side are as follows : 



Square miles. 



The Northern Hirrh Level takes the drainage of Hack- 

 ney. Homertori. Stoke Xewinsrton. Stamford-hill, 

 Hornsey, Holloway. Kentish-town. Hani: 

 Hislwrate, and other localities, the total area of 

 which is .......................................... 9f 



The Middle Level takes the drainage of Bow. 

 end, Bethnal-green, Shoreditch, Kinprsland, ! 

 ton, part of the City, Clerkenwell, ilolborn. Oxford - 

 street, and from Bayswater to Kensal-srreen, and 

 other localities, the total area of which is ...... ..... 17} 



The Low Level takes the drainage of Poplar, Lime- 

 house. ShaJwell. Kadcliffe. part ~ot the City of Lon- 

 don, A'-. 1'imlico, Chelsea. Bromnton, Ful- 



ham. Hammersmith, and adjoining localities, the 

 total area being .................................. 



Total. 



The northern outfall r. 

 the point where Durki;:. 

 Thames, a little c:i-- ! 1H 



miles below London-bridge. ] :* an 



area of about t :,<1 h capable of con- 



taining G.243,000 cubic 

 gallons. Its depth is abon 

 it is divided into four compartment*. There 

 are sixteen openings in the sH- ntfall 



:-s through which the .sewn ire flows into 

 the reservoirs, as regulated by 

 and underneath them are sixteen op- 



regulated by penstocks, for the outflow 

 of the sewage into the river at the tin; 

 scribed. The discharge culverts into tho 

 river are visible only at the time of low Avater; 

 they are nine in number, and in front of them 

 is a stone-paved apron, over which the ? 

 glides, Avithout leaving any deposit, into tho 

 river. 



The machinery provided is of 500 nominal 

 horse power, consisting of four double-acting 

 condensing engines, each working two single- 

 acting ram-pumps, or sets of plungers. The 

 beams are 40ft. long; the fly-wl 

 diameter and 50 tons weight each ; the cylinder 

 is48in. diameter and 9ft. stroke; and the plung- 

 ers (eight to each engine) are 4' 6'' diai:. 

 half of them with 4' 10'' stroke, ar.d the re- 

 mainder with 2' 3" stroke. The pump- 

 are 12ft. diameter ; the two delivery-troughs 

 or outlets from the pumps are each 32ft. long, 

 mft. wide, and 10ft. high. The 12 boilers 

 are each 6ft. diameter and 30ft. long, The en- 

 gine-house is about 154ft. long, and about 53ft. 

 Avide; the boiler-house about 112ft. by 64ft. 

 The chimney-shaft when completed, will be 

 about 200ft. high ; the coal-sheds extend along 

 one side of the reservoir for a length of about 

 530ft., and are about 48ft. Avide. The enfire 

 area of the works, including the reclaimed 

 ground and adjoining land, is about 30 

 A telegraphic wire is fixed along the centre of 

 the arch of the outfall sewer between Deptford 

 and Crossness, so that in case of accident to 

 the machinery or other works at either end the 

 fact may be instantly made known and : 

 ance procured. The southern reservoir has 

 an area of about six and a half acre-, 

 teen feet deep, and is capable of holt! 

 000 cubic feet, or 27,000,000 gallons, in its four 

 compartments. 



The drainage from the loAv-lying districts of 

 Rotherhithe, Bermondsey, Xev, iii-ton, Yaux- 

 hall, Wandsworth, Putney, and otL 

 Avill be preA'iously pumped at the station at 

 Deptford Creek from the low-K- up to 



the high-level sewers, Avhich the 



drainage of Kunhead, Dulwk-h, Xorwood, 

 Brixton, and Clapham. From Deptford the 

 united stream will flow through the outfall 

 : to Crossness pump: . where it 



will be lifted into the reservoir. The maximum 

 quantity of seAvage to be punr ated 



at 8,000 cubic feet per minute, and the lift as 

 varying from 10 to 20 feet. Triple cu'. 



