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123
Act, 1871." Dr. Frankland's report deals mainly with the quality
of the water in its chemical and microscopical aspects, and in
relation to its fitness for dietetic and domestic purposes; he being,
as is well known, adverse to riparian sources of supply: whereas
Colonel Bolton's observations have reference inter alia to the
condition of the water in bulk at the intakes, and to its physical
qualities when delivered to consumers—in other words, to
the machinery for collection, subsidence, filtration, storage, and
distribution.
London is mainly supplied from the rivers Thames and Lea, and the New River;
but a considerable and increasing quantity of water is obtained from deep wells
sunk in the chalk, not only by the Companies which obtain their entire 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 was 34 gallons. This is greatly in excess of what is required, and
indicates waste.
Dr. Frankland is as emphatic as ever in his commendation of "deep well water,"
and takes it as the standard of purity in comparative observations on the waters
generally. He describes 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," moreover, 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." At present the inhabitants of the Metropolis, generally, can only use it
after it has been mixed with the excrements of a large population, and used for
the washing of vast quantities of filthy rags in paper mills, and of linen in
laundries. It would be a most valuable boon to London, he thinks, 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
addition of slaked lime, a process equally applicable to all waters supplied to the
Metropolis.
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
20°.2; of the Kent Company's water 26.6; and of the Colne Valley Company's
water only 6°.3. "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, at least eighty times as much (in soap and soda) as
it costs when conducted on a large scale by a water company." The only water fit
for "washing" delivered in London during the past year was that of the Colne