gement as
large a proportion of the sewage as practicable is carried away by
gravitation, and a constant discharge for the remainder is provided by
means of pumping. At the outlets, the sewage is delivered into reservoirs
situate on the banks of the Thames, and placed at such levels as enable
them to discharge into the river at or about the time of high water. The
sewage thus becomes not only at once diluted by the large volume of water
in the river at the time of high water, but is also carried by the ebb 26
miles below London Bridge, and its return by the following flood-tide
within the metropolitan area, is effectually prevented."

The details of this stupendous enterprise are of sufficient interest to
justify the introduction here of the "General Statistics of the Works" as
reported by the Board.

"A few statistics relative to the works may not prove uninteresting. The
first portion of the works was commenced in January 1859, being about five
months after the passing of the Act authorising their execution. There are
82 miles of main intercepting sewers in London. In the construction of the
works 318,000,000 of bricks, and 880,000 cubic yards of concrete have been
used, and 3,500,000 cubic yards of earth excavated. The cost, when
completed, will have been about L4,200,000. The total pumping power
employed is 2,300 nominal horse power: and if the engines were at full
work, night and day, 44,000 tons of coals per annum would be used; but the
average consumption is estimated at 20,000 tons. The sewage to be
intercepted by the works on the north side of the river, at present
amounts to 10,000,000 cubic feet, and on the south side 4,000,000 cubic
feet per day; but provision is made for an anticipated increase in these
quantities, in addition to the rainfall, amounting to a total of
63,000,000 cubic feet per day, which is equal to a lake of 482 acres,
three feet deep, or 15 times as large as the Serpentine in Hyde Park."

A very large portion of the sewage has to be lifted thirty-six feet to the
outfall sewer. The works on the north side of the Thames were formally
opened, by the Prince of Wales, in April 1865.

In the hope that the immense amount of sewage, for which an escape has
been thus provided, might be profitably employed in agriculture,
advertisements were inserted in the public journals asking for proposals
for carrying out such a scheme; and arrangements were subsequently made
for an extension of the works, b