Tuomson.—On the Cleansing of Towns. 65 
mound, close to the south bank of the Thames, and on which are also 
erected official and workmen’s houses, with a school for the children. The 
mound is actually a covered tank of six acres in extent, but being covered 
with earth, and planted with grass, this cannot be detected by a stranger. 
The engine-house is a spacious erection of the Byzantine style, the 
-chimney-stalk being of elegant proportions. The power of the engines 
is 500-horse, and is used in pumping the sewage from the main drain 
into the tank, by means of eight plunge pumps, of about three feet in diameter. 
The main drain is 80 feet below the surface, and the tank rises above this, 
having a depth, when full, of 14 feet. 
The sewage is only let out at high-water, on its turn to ebb, and it con- 
tinues to flow till nearly low-water. There are three outlets for the sewage 
from the tank into the river, constructed of solid brick and cement, leading 
to the high-water mark, then by open timber ducts to the low-water mark. 
It was near low-water mark when I visited the place, and I could not 
markedly detect offensive smell, but the water of the river was exceedingly 
turbid and discoloured. 
I also examined the sewage in the tank, through a manhole, and ascer- 
tained that but slight offensive odours escaped by this aperture. 
I did not consider it necessary to examine the works on the north side 
of the river, as the principle is merely repeated, but they are larger, the 
tank there being equal to 10 acres. 
The effect of the outfall of eity sewage and detritus in a river, then, is 
similar to what may be readily studied on any goldfield where hydraulic works 
in simple gold-washings are in force. The sludge does not pen up the rivers 
of magnitude, but it merely spreads itself out on the banks adjacent to the 
outfalls, and what it occupies of the original bed, the stream compensates 
itself by scouring out a deeper channel on the opposite, so that it maintains 
an equal volume. Limiting the enquiry to navigation, such, in our view, 
is the influence on the Thames in this much-vexed question. 
In regard to its pollution, that is another question. We cannot help 
opining that Captain Calver is more eloquent on this subject than necessary. 
That fetid matter is carried up to the metropolitan area, teeming with popula- 
tion, contaminating its area, is surely their grievance, not his; and so long 
as they are contented with the smells in their precincts, the Thames Con- 
servancy need not disturb themselves, but if they can show that ship and 
barge crews are struck with gastric fever, or otherwise intolerably discom- 
posed by the odours, by passing the outfalls, this comes within their 
functions to remedy, But no statisties are brought forward on this head, 
nor are complaints from this quarter even alluded to. 
Looking at the question with a bird’s-eye view, in our humble kag 
