View report page

161
tion of the solid matter is of an organic nature. Organic matter is always
objectionable in water used for drinking, and such matter, when present in
river water, is sometimes dangerous to health.
The deep-well waters delivered by the Kent Company and by the Tottenham
Board of Health, contained the largest proportions of solid matter; but the
deep-well water, derived from the same source, and supplied by the Colne
Valley Company, contained less than one-third the quantity found in the river
waters, and less than one-fifth of that found in the Kent Company's water:
this comparative freedom from saline matters being attained 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 improved by being submitted
to the same (Clark's) process.
The organic impurities found in the river waters, derive their importance
from being chiefly of animal oirgin. 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, it beiug no longer necessary to impound
the worst flood waters, the average quality of the water supplied during
the greater part of the year was better than usual: nevertheless the water in
times of flood was often largely polluted with organic matter, and unfit 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. A great improvement might, however, be effected, if to the sand
an additional filter bed of spongy iron were added. The process of filtration
through spongy iron has already been adopted on a large scale in Belgium with
marked success. Deep-well waters undergo 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 known to be
prejudicial to health, should have escaped removal. Hence these waters are "uniformly
pure and wholesome." Of the river water abstracted from the
Thames, the best average supply was furnished by the Lambeth Company.
The water supplied by the West Middlesex Company was bracketted with that
of the Southwark Company as containingthe largest amount of organic impurity.
A marked and undeniable advantage of spring water is its evenness of
temperature. The range of temperature of river waters is considerable,
aud last year in the water of the Thames, as delivered by five of the Companies,
it amounted to 28°.o Fahr., viz., from 40°.5 in January to 680.5 in August. The