The water flows through this main into a reservoir in Kennington Lane, from which it percolates through a filtering bank, composed of layers of coarse and fine gravel and sand, prior to its entering into another reservoir, where it also remains some time, before it is passed into the well of the

distributing steam engine. The supply of this company extends to 12,000 houses, and exceeds 5,000,000 gallons daily.

To complete this view of the works, which supply London and its suburbs, containing probably nearly 1,200,000 inhabitants, we annex, in a tabular form, extracts from a more extended return, made by these companies in 1834, to Parliament. It exhibits the

number of houses supplied, the average quantity to each, the aggregate of the whole supply of every company, and all the companies, the level at which it is furnished, and the average cost to the consumer.

A TABLE, Showing- the number of Houses supplied by the Water Companies of London, according to returns made to Parliament, in 1824.

Names of Companies.

60 PRELIMINARY ESSAY.

two derive their supply from the Thames abreast of the city, All the companies but and where the sewers empty into it, and all the filth of a crowded population. They all have recourse to steam engines, to raise their supplies to a height sufficient for distribution.

The large iron mains, which project out nearly half across the river in some instances, are laid upon the bottom ; a method that could only be resorted to with safety in a river where there is but boat and barge navigation, as is the case with the Thames above London Bridge otherwise, these pipes would be in constant danger from the anchoring of ;