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used, thus reducing the amount of land required. The land, however,
has yet to be found, and in any case a large outlay would
be required on main and branch sewers, etc. Projects for conveying
the sewage to the land have been before the public for
thirty years and more, and nothing has been done. Probably it
will be long before anything will be done. The questions remain,
therefore, Is the river of necessity to continue to be polluted as
heretofore ? Is there no alternative ? Three schemes have
been put before the public lately, viz :—(1) The Amines process ;
(2) the International Sewage Purification process; and (3) the
Webster Electrical process, which appear to deserve notice.
The Amines process was tried at Wimbledon on a fairly
large experimental scale. Lime was added to the sewage in
considerable quantity, mixed with herring brine in the proportion
of three grains to the gallon. A good effluent, apparently sterile,
was produced. It was believed by many, however, that most of
the effect produced was due to the large addition of lime, and a
somewhat general impression prevailed that the process could
not be regarded as applicable to the case of the London sewage.
The International and Electrical systems appear to be
decidedly superior, and both are vouched for by Sir Henry Roscoe.
Both, moreover, are at the present time undergoing exhaustive
competitive trials, side by side, at the Salford sewage works.
The International process consists, firstly, in the precipitation
of suspended matters by " ferrozone," about eight grains to
the gallon being used : this substance contains 26½ per cent. of
ferrous sulphate and 2 per cent. of aluminium sulphate, and costs
£3 per ton. Secondly, after subsidence in tanks, the effluent is
drawn off and passed over filtering beds at the rate of 1000
gallons per square yard of filter in 24 hours. The filtering
material is " polarite," which contains about 54 per cent. of
magnetic oxide of iron; the cost of the filter being about 14s. per
square yard, or £4 per ton. The process is in operation at Acton,
upon what may be described as a purely domestic sewage, a good