40 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



LFebbuaby, 



not choose to pet themselves involved in a contest with the cor- 

 poration of London. 



The City t'ommission of Sewers has certainly been amon;; the 

 best managed, and this, perha])s, for the reason that they have 

 jdHays had a reffular corps of officers; but still there is no i-eas<jn 

 why the city should not derive tlie benefit of an amalf^amation with 

 the rest of the metropolis. Let the cor](oration choose a commis- 

 sioner, and they will jret a share of the influence, control, and 

 ]iatr(inaj?e, as well as of the economy attendant on tlie new com- 

 mission. If they do not accede at once they w ill not be aide to 

 secure tlie few dinners which they receive, while they w ill lose the 

 power and patronanfe. At present tlie street sewers i)f the city are 

 imperfect and unflushed, the ffratiiisrs and jfully-holes untrap- 

 ped, the courts and alleys undraineil, the footways and foot- 

 ])avemeuts not cleansed, the house drains and cesspools in a dan- 

 gerous condition, wliile the sewers convey miasma into most of the 

 liouses. The statistics of the city in the latter respect are most 

 unfavourable, and show a. fearful influence on the public health. 



The commissioners have pven such evidence as to the necessity 

 of consolidating: the districts, that on the streng^th of that evidence 

 we call iipon them to complete their measure of amalgamation. 

 They say — 



"Taking the works of cleansing as they now are, the preventive 

 measure to whicli those works may be immediately ajiplied with 

 the greatest advantage is that of flushing. But to the general and 

 effectual application of this most important operation, tlie state 

 and separation of the several districts under the district commis- 

 sions, presents itself as an insuperable obstacle ; and, in fact, the 

 operation of cleaning out the sewers by flushing them witli water 

 is in systematic use in only one of the upper districts, the Ilolborn 

 iind Finsbury district. 



" One district may flush its sewers, but the operation will be at 

 many points only a removal of a portion at least of tlie refuse into 

 the sewers of the adjacent districts, unless the operation be con- 

 tinued tlirough the intermediate districts to the outfall. The lower 

 districts complain of being encumbered by the flushing operations 

 in the upper districts. 



" In the lower districts, which are flat, there are generally accu- 

 mulations of refuse, and if in an upper district, which is under a 

 separate jurisdiction, a part of tlie line of sewer is flushed to keep 

 it free from deposit, the effect upon tlie lower district in which the 

 flush exhausts itself, is to disengage more copiously the offensive 

 emanations, for a time, by disturbing and adding to the deposit 

 there, without removing it. Wliilst the sewers of one district are 

 left unflushed, or uncleansed, the emanations are driven by the 

 wind into other districts, particularly from the deposits at the 

 moutli of se« ers in the lower to an upper district. ^V^hen the 

 sewers in the Holborn and Finsbury division have been clean 

 fluslied, it is stated tliat tlie inhabitants of that district, even up 

 to the New River Head, have been annoyed by the currents of 

 offen.sive gases up the sewers from the accumulations in the lower 

 districts, where the same cleansing operations have not been car- 

 ried on. For obxious reasons, additional supplies of water would 

 require to be provided in the upper districts, and regulated, for 

 application througliout the whole lines to the outfalls, without 

 staying for separate and intermediate co-operation." 



One great evil of the present system, and a cause of fearful ex- 

 pense, is the disproportion between the area of the sewage sent 

 through sewers and the area of the sewers themselves. 



" Works to effect town drainage must be constructed for the re- 

 moval of surplus or waste water from two sources; the natural 

 rain-fall on the town area, together with water from the springs 

 ilerived from sources beyond the area which may often require 

 sepai-ate arrangements ; and tlie jiipe-water, brought into the town, 

 and any refuse matter wliich it may have received in suspension or 

 chemical combination. Setting aside for the jiresent the consider- 

 ation of the house drainage, and taking in the first instance, the 

 secondary sewers, we give the following cross section, fig. I, of a 

 sewer draining two or three streets comprehending between one 

 and two hundred houses. The depths of the ordinary run of sevfer- 

 water when there is no rain, is only about tliree inches, and the 

 depth of the increased run of water on tlie occasions of the greatest 

 storms, just covered tlie invert. 



" The cross section, fig. 2, is a section of a main line of sewer in 

 the Westminster district, draining about 90 acres of town area. 

 The ordinary run of sewer-water does not cover the invert, and 

 on the occasion of the greatest thunder storm of which tliere i.s 

 .-:ny liistorical record in tlie metropolis, namely, that on the 1st of 

 August, ItHti, the flow of water was only 2 ft. 3 in. deep. 



'-In general tlie flow of water in the collateral sewers of branch 

 lines of street, even where all the liouses drain into them, are mere 



dribbles, and rarely rise above the invert of the wide bottomed 

 severs as at present constructed, even in streets where all the 

 luMises drain into tli« sewers. The following are tlie coiise(|uences 

 which take place in various degrees in nearly all the collateral 

 sewers of every form of construction, though the best is the egg- 

 shape form. 



'■ Tlie flow of water, being impeded, by the extent to wliich it is 

 spread, is retarded, and a deposit is created ; this deposit becomes 

 indurated to a degree which prevents its being remo\ ed by the 

 flow of water occurring in ordinary rainfalls, and is not often con- 

 siderably affected by any otlier than the extraordinary storms 

 which occur in intervals of several years. 



"The accumulations continue, and during the process, the de- 

 posit from the house drains spreads on the sides, and decomposition 

 ensues. 



" The accumulations in the sewers, as well as in the large house 

 drains wliich communicate with them, are exposed to the action of 

 much air, usually at such a temperature as greatly to facilitate 

 decomposition. 



" The accumulations increase until the house drains are entirely 

 stopped up, when the deposit in the sewers is usually removed by 

 the offensive process of hand labour and cartage, leaving the de- 

 posit in the house drains untouched." 



It is well observed that very small currents suffice to keep sewerg 

 clear of deposit, if the inclination be good, and the flow be concen- 

 trated and kept regular, for which it is considered tliat additions 

 of small quantities of water would be suflicient at particular inter- 

 vals and seasons. The commissioners therefore recommend the 

 use as far as possible of glazed earthenware tubes. These were 

 long since tried by Mr. Roe in the Holborn and Finsbury di^•ision, 

 and afterwards by Mr. Phillips in the ^^^estminster division, and 

 found to discharge the water more quickly and to keep clear of 

 deposit. They also prevent the passage of rats from the sewers 

 into houses, because they afford no hold, and do not, like the com- 

 mon brick drains, allow them to make burrows. 



Mr. Roe and Mr. Phillips also made observations on the flow of 

 water from the main and side sewers and drains, which the former 

 began so long as five years ago. 



In Mr. Roe's experiments he ascertained the rate of flow of water, 

 through the common brick drains for houses, as well as through 

 earthenware drains of the same capacity, and with the same run of 

 water. As a general result it may be stated that the rates of dis- 

 charge through earthenware pipes are ^'ery much increased, some- 

 times as much as one-third. In the application of water for flush- 

 ing, this is an important consideration, as by the use of the im- 

 proved drains, a great saving of water will lie effected. 



The house drains receive the water from small Ig-inch lead 

 pipes from the kitchen sinks, and yet they are often made as much 

 as 60 times the capacity of the pipes in the smaller houses. In 

 these, square brick drains are put in, costing from 6rf. to llrf. per 

 foot run, exclusive of digging, while in the larger houses brick 

 bari'el drains of 9 or 12 inches diameter are put in, costing I*, id. 

 or 1.?. 7rf. per foot run. As the bottom joints are put in without 

 mortar or cement, the sewer water percolates through the drain, 

 and infiltrates into the houses, while the solid matter, unwashed 

 by any stream of water, festers at the bottom, and acts as a retort 

 for supplying nauseous gases to the houses. It is true that the 

 object in leaving the bottom of the sewers " dry," or without mor- 

 tar, is to let in the land drainage, but the effect is what we have 

 stated, while it is rare to find a house drain free from deposit. 

 The rats, too, by burrowing in the drains, put them out of order, so 

 as to require their more frequent repair, and the whole working of 

 the drains is as unfavourable as can be conceived, and as far as 

 possible from the designs of the builders. A common house drain 

 cannot be considered otherwise than as a nuisance. 



A twelve-inch drain is an expensi\e nuisance, w bile an earthen- 

 ware pipe of four inches diameter (or, proportional to the house, 

 of from tliree to six inches diameter,) keeps perfectly clear, and a 

 three-incli pipe is found quite large enough to carry away the 

 refuse from middle-sized houses. In consequence of the adoption 

 of this improvement, the cost of drains from houses to sewers in 

 the Westminster division, wliich used to be from i^lO to £25, 

 has been brought down to a charge of from £2 ISs. to £i 10s., and 

 even this is considered too high. 



Nothing shows the error of the old system more strongly than a 

 case given by Mr. Phillips of drains in Langley-court, Long-acre. 

 An old small sewer, 18 in. wide by 2 ft. high, having a good fall, 

 was nearly dean, while a new sewer, 5 ft. 6 in. liigh by 3 ft. wide, 

 contained an average depth of three feet of soil, and the emana- 

 tions from it caused the death of a poor man, and led to an in- 

 quest. 



