80 



THE CIVIL ENGINEKR AND ARCHITECT'S JOURNAL. 



[^Mabcu, 



from absorptiiin, t]ie detention from friction, and otherwise, that 

 (luaiitity mifrht lie reduced to four-fifths of a culiic foot, but as the 

 cjirryiiii,^ off the waste water of the entire of London must be pro- 

 vided for at the same time, one cubic foot may, I think, be con- 

 sidered as tlie datum upon which to calcuhite the capacities of 

 sewers sufficient for conveyinf; away that (piantity of water per 

 second multijilied by the number of acres to l)e drained. The 

 quantity of rain-water draininff from an acre of frround in one 

 second of time may be determineil by first ascertaininf; the exact 

 area of surface ilrained by some lartre main sewer; and, secondly, 

 during the time of the storm, the quantity of water passing through 

 the sewer in one second ; then the number of cubic feet of water 

 discharu;ed, divided by the number of acres drained, will give the 

 number of cubic feet of rain draining from the surface of each acre 

 per second. 



The area of surface that a sewer will drain, and the quantity of 

 water that it will discharge in a given time, will be greater or less 

 in proportion as the channel is inclined from a horizontal to a ver- 

 ticiil position. The ordinary or common run of water in each 

 sewer, due from house drainage alone, and irrespective of rain, 

 should have sufficient velocity to prevent the usual matter dis- 

 charged into the sewer from depositing. For this purpose it is 

 necessary, as I ha\'e previously observed, that there should be in 

 each sewer a constant velocity of current equal to 2S feet per 

 second, or if mile per hour. The. inclinations of all rivulets, 

 brooks, streams, and rivers gradually and proportionally diminish 

 as they progress from their sources to their outfalls. In propor- 

 tion as the inclinations diminish so does the quantity of water in- 

 crease. If the inclinations were the same throughout, the velocity 

 of the united stream at each confluence would increase in nearly 

 the same ratio as its quantity, or equal to the sum of the previous 

 velocities of the recipient and the feeder, and thus would the velo- 

 city ultimately become so very impetuous as to tear up and sweep 

 away the materials of its bed, and cause destruction along its banks. 

 If the force of the waters of the river Rhone were not absorbed by 

 the operation of some constant retardation in its course, the stream 

 would have shot into the Bay of Marseilles with the tremendous 

 velocity of 210 feet in a second, or let miles every hour ; and even 

 if the river Thames met with no system of impediments in its 

 course, the stream would have rushed into the sea with a velocity 

 of 80 feet per second, or 54A miles in an hour. The result, how- 

 ever, of the operations of nature is a compensation for the increased 

 body of water by a diminution of the inclination of the bed, and so 

 an economising of the force of the gradually accumulating current. 

 The inclinations of the sewers of a natural district should be made 

 to diminish from their heads to their outfalls in a corresponding 

 ratio of progression, so that as the body of water is increased at 

 Cflch confluence, one and the same velocity and force of current 

 may be kept up throughout the whole of them. 



In some situations I would build side entrances to a tubiJar sys- 

 tem of sewers ; but I believe their use, in some degree, might be 

 superseded. Means of access to the sewers, so as to be able to get 

 at and remove accidental obstructions, would readily suggest them- 

 selves. A shaft, having a strong moveable grating on top, could be 

 built over the sewer, with ladder-irons built in the angles, to admit 

 a man to go down and up, with a recess at the bottom on one side 

 to give room. This shaft may be also made to serve as a ventila- 

 tor. (See figs. 6 and 6, Plate V.) 



Giilli/ Drains. — I have constructed gully drains with terro-me- 

 tallic and glazed stone- ware pipes of 6 inches and 9 inches diameter, 

 a.s shown in figs. 7, 8, 9, and 10. I was led to recommend the 

 adoption of this mode of construction from the following causes : — 

 111 passing through the sewers I found lying opposite the vents of 

 a large number of the gully drains heaps of stones, and all kinds of 

 streets refuse, which it was utterly impossible for the water to re- 

 move. The dams thus formed caused the sewage to accumulate 

 behind them, and the noxious effluvia evolved from the decompos- 

 ing matter escaped into the streets by the gullies, and occasioned 

 much of the annoyance felt by passengers. The best remedy for 

 this evil appeared to me to be to prevent the stones and street re- 

 fuse from passing into the sewer.s, t ■ build the drains so that they 

 woTild not choke up, and to prevent the emission of foul air from 

 the sewers into the streets by the gullies. We have accomplished 

 the.se things most perfectly, by reducing the width of the spaces to 

 I inch between the bars of the guUy grates, by constructing the 

 drains of the form shown by the section from the gully to the 

 sewer, and by fixing at the vent an air-tight cast-iron valve or flap, 

 hung with shackles, as shown in figs. 11 and 12. A grating of 

 trellis-work or cullender is placed under the top grating, at the 

 bottom of the box, for the purpose of catching small stones and 

 rubbish that may pass between the bars of the grate above, and so 



to prevent them from falling into and choking up the sewers. I 

 have not, as yet, mtule use of the lower gr.itiug, but probably, I 

 should be induced to do so in connection with a tubular system of 

 sewers, as it is important to keep large and heavy substances and 

 refuse out of the drains and sewers. I may state that as a proof of 

 the efficacy of the foregoing mode of constructing the gully-drains 

 with the improved grate, the labour and expense of cleaning, not 

 only of the gully-drains, but of the sewers as well, is now, com- 

 paratively speaking, nothing compared to what they used to be, 

 and I confidently entertain an opinion that the labour and expense 

 will be still less and less." 



Mr. Phillips has just produced his report on the improvement of 

 the drainage of Westminster, and which has been printed. This 

 document is of great importance, and we are pleased to see that 

 most of our suggestions on this subject have been adopted, parti- 

 cularl)' with reference to turning part of the drainage into the 

 Regent Street Commissioners' Sewers. Mr. Phillips proposes to 

 divert the high level streams to a station at the east end of Dun- 

 cannon-street in the Strand, to bring the AVestminster drainage to 

 the same station, and to apply the natural power thus to be ob- 

 tained to work two water-wheels of the most approved construp- 

 tion, with revolving buckets and plunger-pumps attached, to lift the 

 drainage from the well or receiving reservoir below, and dischai^e 

 the same into channels communicating with the upper stream on a 

 level with high water, beyond the tail of the wheels. The sewage 

 wUl then be carried under the side-bed of the river into low-water 

 stream. 



Below we give a summary of Mr. Phillips' estimates, which make 

 a total of £28,874 lis. 



Estimate for building a Gully Drain, average length 20 feet. 



& s. d. 



Six cubic yards Digging, itc, at Is. 6d. .. .. 9 



Twenty feet run of 4 in. Pipe, at 84d 14 2 



Gully Grate (about \\ cwU) including bedding and 



fixing .. .. 16 



Total .. .. £1 19 2 

 About 400 Gully Drains will be required, which at, say 11. each, amounti 



to £800 



Estimate for building a Sewer along Pall-Mall-East, Trafalgar-square, Dun- 

 cannon-street, Strand, and Villiers-street, for diverting the Western and 

 Eastern branches of the Hartshorn-lane Main sewer, — being a length of 

 2,230 feet, at 18s. per foot £2,007 



Estimate for Two Water Wheels, with complele Lifting Machinery 

 attached, and including all necessary work. 



£ I. d. 



Brickwork— say 40 rods at 10/. 400 



Two Water Wheels, at 200i 400 



Lifting Machinery — say 200 



Total .. £1,000 



REFERENCE TO ENGRAVINGS, PLATE V. 



Fig. 5.— Section of Shaft on A A. 



Fig. 6.— Plan nt Shaft. 



Fig. 7.— Section of Gully Drain from Grating to Sewer. 



Fig. 8.— Plan of Gully and Grallng. 



Fig. 9.— Transverse Section of Gully and Grating on A B. 



Fig. 10.— Longitudinal Section of Gully and Grating on C D. 



Fig. 11.— Section of Drain and Flap at Vent. 



Fig. 12. — Front View of Flap. 



Fig. 13.— Mode of Striking ttw Curves. 



