SEWAGE OF LONDON AND OTHER LARGE TOWNS. 149 
one seventh part of this fertilizing matter by any known 
economical process; that a copious dilution of the sewage 
is necessary to the health of the inhabitants of the metro- 
polis; and that therefore the sacrifice entailed by the dilu- 
tion must be endured.” — The plain meaning of all this I 
take to be: We will take care to dilute and remove the sew- 
age, and then when, as we have shown, private enterprise 
will be unremunerative, we will invite it. 
Sketch of the scheme of the Metropolitan Board.— On 
the north side the scheme consists of a main high-level 
sewer, to intercept the fall from the higher parts, extending 
from Hampstead; a main middle-level sewer from Kensal 
Green; and a main low-level sewer from Vauxhall Bridge 
Road. All these terminate near Bow, whence the united 
streams pass in a channel formed of a triple culvert of 
brickwork to Barking Creek. On the south side a similar 
system of high-level and low-level sewers is to extend 
from Clapham and Putney to Greenwich, and thence to be 
carried forward in one main through Woolwich to Cross- 
ness Point, a place midway between Woolwich and Erith. 
Pumps are to be employed to raise the sewage at certain 
points, and storm-overflows are to enable the mains to dis- 
charge themselves through the previous system of sewers 
into the river within the limits of the metropolis, when- 
ever in consequence of a sudden fall of rain the former are 
overcharged. Two large reservoirs are to be placed at the 
outfalls of the two great mains, with the object of retaining 
the sewage until after full tide, when it is to be discharged 
into the Thames. 
The utilization of sewage is virtually ignored in the 
scheme of which I have just given an outline. Will it 
answer the object for which it is solely designed — that of 
purifying the Thames, and increasing the healthfulness of 
the district? To reply to this question, we must consider 
lst the operation of the principle of intercepting and di- 
