12 JANUARY 1878, Page 14

THE THAMES AND LONDON SEWAGE.

[TO THE EDITOR OF THE SPECTATOR:]

1827 a Company was formed for embanking the River Thames, and conveying the sewage of London, by means of a tunnel under the embankment, down to the Isle of Dogs, there to be converted into manure for sale.

On being consulted, I reported that the excluding the tide from entering the sewers and expelling the foul air from them, which was supplied by fresh air on the receding of the tide, would be fatal to the health of London, and. render it the land of Golgotha ; and that the tunnel would be blocked up by the debris from the streets and the sewers running into it at right angles, unless a powerful body of water from the upper part of the river was flushed through it, which would render the sewage of no value. The scheme was dropped. In 1859, on hearing that a similar plan was about being adopted, I called on one of the most eminent members of the Institution of Civil Engineers, and after telling him of the above objections to the proposed scheme, I suggested that the object of purifying the Thames might be effected by tapping the river in that section where the same fcetid matter oscillated backwards and forwards daily by the tidal action.

When the best locality was decided on, a canal could be cut from it, through the Essex Marshes, to the sea, clear of the River Thames, which would require gates, locks, and sluices, only at both ends.

The gates to be worked by the electric telegraph. On the flood tide the sea-gate would be shut, and the river-gate kept open, to enable the canal to be filled by the flood tide with the offensive matter.

And as the tide rises for two hours at London Bridge after the ebb makes at the sea-gate, the canal would act as a syphon, until the following flood tide rendered it necessary to shut the sea-gate.

By adopting this plan, the velocity of the flood tide will be in- creased to supply the vacuum caused by the discharge from the canal, to the great improvement and scouring of the river, and in a few weeks the pure sea-water would reach the river entrance to the canal, and finally up to Chelsea, above the sewers. I have been informed that the canal could be constructed for £1,000,000 sterling.

By the present system all the sewers are closed from the tidal action, and after being pumped up from different levels, the sewage is finally discharged into the River Thames at Barking Creek on the north and Crossness on the south side, from whence the ebb tide cannot convey it clear of the river before it is met by the flood tide, which brings it back, causing it to subside at slack water in the bed of the river, which, in course of time, will seriously injure the navigation.

Were the canal constructed, it is probable that if the land- owners were allowed to have sluices in it, to extract the liquid manure for their lands, they might be induced to charge little or nothing for the area required for its construction.-1 am, Sir,