View report page

121
is userl for dietetic purposes, but a small proportion consists of organic substances
which are always objectionable, and at times are dangerous to health. The
average proportion of total solid matter was rather less than in 1880. The
deep-well waters delivered by the Kent Company and by the Tottenham Board
of Health, contained the largest proportions of these matters; but the deep-well
water, derived from the same source, and supplied by the Colne Valley Company,
contained less than one-half the quantity found in the river waters, and less
than one-third of that found in the Kent Company's water: this comparative
freedom from saline matters being attained, as already explained, by adding a
small quantity of slaked lime to the water before it leaves the Company's works.
All the water supplied to the Metropolis would be equally improved by being
submitted to the same process.
The organic impurities found in the river waters, derive their importance from
being, to a great extent, of animal origin. Owing to the careful filtration to which
the river water was generally subjected, together with the improved means of
storage at the command of the Companies, the average quality of the water supplied
during the greater part of the year was better than usual; nevertheless, in
January, February, March and December, the river water supplied by most of
the Companies was "much polluted with organic matter and not fit to drink."
The "noxious organic matters" are "in suspension," but in such a finely divided
state as to render their removal by artificial filtration through sand impossible.
There is thus no protection against the distribution of them in polluted river
water. Deep-well water, on the other hand, has undergone such a prolonged,
exhaustive and inimitable natural filtration through great thicknesses of porous
strata, as to render it extremely unlikely that any suspended organic matter
should have escaped elimination. Hence the deep-well waters are "uniformly
pure and wholesome." Of the river water abstracted from the Thames, the
best average supplies were furnished by the Chelsea and Grand Junction Companies.
Not many years ago the supply by the Chelsea Company was one of
the worst, owing to the unsatisfactory position of their intake—at Seething
Wells—and to deficiency of storage reservoirs, but the Company having removed
their intake to West Molesey, undertaking extensive works at a large outlay, now
supply water superior in quality to that of the West Middlesex Company, which
for several years was at the head of the Companies drawing their supplies from
the Thames, but whose water in 1881 showed on an average a larger proportional
amount of organic elements than either of the other local Companies, as is seen
in the following table, which shows the amount of organic matter in the water
of the Companies which supply Kensington, the Kent Company's water being
taken as the standard of purity for comparison:—
Name of Company. Maximum. Minimum. Average.
Kent 19 1.3 16
Chelsea 68 2.3 3.9
Grand Junction 6.4 2.4 3.8
West Middlesex 6.5 2.3 4.2
The organic elements consist chiefly of organic carbon, and the maximum
pollution in the river waters greatly exceeded the standard, which is—10 part of
organic carbon in 100,000 parts of potable water.
A marked and undeniable advantage of spring water is its evenness of