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vapid, and at 35.8° is soon cooled to the freezing-point." Dr.
Frankland refers to the "hardness" of the waters, which is
almost entirely due to the presence of bicarbonate of li.ne in
solution, "which in no way diminishes the fitness of the
water for dietetic purposes," but makes it unsuitable for washing,
and also causes incrustations and deposits in steam and
kitchen boilers and hot-water pipes, thus diminishing its value
for industrial purposes. The hardness can be largely reduced
by Clark's softening process, By this process, which consists
in treating the water with lime, the initial hardness of the
Colne Valley Company's chalk water, which is much in excess
of that of Thames water, is reduced to about a third of the
hardness of river water. The hardness of the Thames
water in 1893, was 19.6°. that of the Colne Valley supply
being 7.1°. The organic material which the solid matter contains,
if present in too large a quantity, may interfere with the
palatability of the water, and give it a more or less brownish
yellow tint. These effects were not produced in 1893. It is
alleged, however, that the presence of even small proportions
of organic matter is objectionable, partly on sentimental
and partly on hygienic grounds, by reason of the origin of a
part thereof, such as the drainage from manured land, effluents
from sewerage works, and even raw sewage itself. This animal
matter " may " be accompanied by zymotic poisons dangerous
to health. These poisons, however, are " rapidly destroyed in
running water exposed to sunlight, and the most minute
microscopic examination of the water at the intakes has
failed hitherto to discover a single pathogenic germ." It is
now an established fact, moreover, "that efficient sand filtration
would prevent the passage of such germs into the filtered
water, even should they arrive in a living condition at the
intakes of the companies. Thus the hygienic objection to the
use of filtered water from the Thames is removed. This conclusion,"it
is stated,'' is confirmed by the absence in London of
zymotic diseases traceable to these waters," during the last 28