London Labour and the London Poor, Vol. 2

by Henry Mayhew

Thus the length made in the 20 years previous to 1847 was more than double all that was made during the preceding 120 years; while in the ten years from 1837 to 1847, the addition to the lineal extent of sewerage was very nearly equal to all that had been made in 130 years previously.

This addition of 127,435 feet, or rather more than 24 miles, seems but a small matter when “London” is thought of; but the reader must be reminded that only a small portion (comparatively) of the metropolis is here spoken of, and the entire length of the City sewerage, at the close of 1847, was but 44 miles; so that the additions I have specified as having been made since 1837, were more than one-half of the whole. The re-constructions are not included in the metage I have given, for, as the new sewers generally occupied the same site as the old, they did not add to the length of the whole.

The total length of the City sewerage was, on the 31st December, 1851, no less than 49 miles; while the entire public way was at the same recent period, 51 miles (containing about 1000 separate and distinct streets, lanes, courts, alleys, &c., &c.); and I am assured that in another year or so, not a furlong of the whole City will be unsewered.

The more ancient sewers usually have upright walls, a flat or slightly-curved invert, and a semicircular or gothic arch. The form of such as have been built apparently more than 20 years ago, is that of two semicircles, of which the upper has a greater radius, connected by sloping side walls; those of recent construction are egg-shaped. The main lines are not unfrequently elliptic; in the case of the Fleet, and other ancient affluents of the Thames, the forms and dimensions vary considerably. Instances occur of sewers built entirely of stone; but the material is almost invariably brick, most commonly 9 inches in substance; the larger sewers 14, and sometimes 18 inches.

The falls or inclinations in the course of the City sewerage vary greatly, as much as from 1 in 240 to 1 in 24, or, in the first case, from a fall of 22 feet, in the latter, of course, to ten times such fall, or 220 feet per mile. There are, moreover, a few cases in which the inclination is as small as 1 in 960; others where it is as high as 1 in 14. This irregularity is to be accounted for, partly by the want of system in the old times, and partly from the natural levels of the ground. The want of system and the indifference shown to providing a proper fall, even where it was not difficult, was more excusable a few years back than it would be at the present time, for when some of these sewers were built, the drainage of the house-refuse into them was not contemplated.

The number of houses drained into the City sewers is, as precisely as such a matter can be ascertained, 11,209; the number drained into the cesspools is 5030. This shows a preponderance of drainage into the sewers of 6179. The length of the house-drains in the City, at an average of 50 feet to each house, may be estimated at upwards of 106 miles. These City drains are included in the general computation of the metropolis.

The gully-drains in the City are more frequent than in other parts of the metropolis, owing to the continual intersection of streets, &c., and perhaps from a closer care of the sewerage and all matters connected with it. The general average of the gully-drains I have shown to be 59 for every mile of street. I am assured that in the City the street-drains may be safely estimated at 65 to the mile. Estimating the streets gullied within the City, then, at an average of 50 miles, or about a mile more than the sewers, the number of gully-drains is 3250, and the length of them about 50 miles; but these, like the house-drains, have been already included in the metropolitan enumeration.

The actual sum expended yearly upon the construction, and repairs, and improvements of the City sewers cannot be cited as a distinct item, because the Court makes the return of the aggregate annual expenditure, as regards pavement, cleansing, and the matters specified as the general expenditure under the Court of Commissioners of the City Sewers. The cost, however, of the construction of sewers comprised within the civic boundaries is included in the general metropolitan estimate before given.

Of the Outlets, Ramifications, etc., of the Sewers.

In this enumeration I speak only of the public outlets into the river, controlled and regulated by public officers.