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supply from that source, but also by some of the old Companies, which
thus supplement their intake of river water. The average daily volume
supplied per head of population in 1883 was 28.4 gallons.
Dr. Frankland is consistent in his preference of "deep well water," taking
it as the standard of purity in comparative observations on the waters
generally. In a previous report he described it as being " delicious and
wholesome," and uniformly excellent for dietetic purposes ; maintaining
that in the interests of temperance and public health, it should, as soon
as possible, be substituted for that portion of the Metropolitan supply
which is drawn from polluted rivers. This "pure spring water," he said,
is " everywhere abundant in the Thames basin: in dry seasons it constitutes
the sole supply of the Thames and the Lea, and, even after the
most protracted drought, more than 350,000,000 gallons of it daily flow
over the weir at Teddington, whilst a further very large volume of it joins
the Thames lower down." He considered that it would be a valuable
boon to London if even a small fraction of this prodigal supply could be
collected, preserved from irremediable pollution, and distributed to those
portions of the Metropolis which are not at present supplied with such
water. The principal objection to it is its hardness, but this is an objection
easily surmounted by " Clark's process."
The "hardness" of water represents the weight of carbonate of lime, or its
equivalent of other soap.destroying substances, found in 100,000 parts
of water. The average hardness of the Thames water delivered in
London last year was 19.9 ; of the Kent Company's water 28.0 ; and of
the Colne Valley Company's water only 7.1 All hard water must be
softened before it can be used for washing linen : when it is softened in
detail by the laundress, the operation costs, for an equal volume of water,
about eighty times as much, (for soap), as it costs when conducted on a
large scale by a water company. The only water suitable for washing
delivered in London during the past year was that of the Colne Valley
Company, which was rendered soft by Clark's process before distribution.
All waters, save artificially prepared distilled water, contain more or less
" solid matter." A large proportion of this solid matter, consists of
mineral salts which are unobjectionable in drinking water, but they render
thewaterhard. A small proportion of the solid matter on theotherhand
is organic. Small quantities of vegetable organic matter are not objectionable
in drinking water, but the organic matter in river water, which
receives sewage, may at any time become dangerous to health. The
task of banishing sewage pollution from the river, is regarded as hopeless.
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 little more than one.third the quantity
found in the river waters, and little more than one.fourth of that in the
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