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167
Metropolis Water Act, 1871. Dr. Frankland, who is adverse to
riparian sources of supply, deals mainly with the quality of the
water in its chemical and microscopical aspects, and in regard to
its fitness for dietetic and domestic purposes; the observations
of the Water Examiner have reference to the condition of
the water in bulk at the intakes; to its physical qualities
when delivered to the consumer; and, in a word, to whatever
concerns collection, subsidence, filtration, storage, and distribution.
London is supplied mainly from the rivers Thames and Lea, 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 in 1886 was 28'6 gallons.
Dr. Frankland is consistent in his preference for "deep well water," taking
it as the standard of purity in his comparative observations on the
supplies of the different companies. In a previous report he described
this water 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 the water is its hardness, but this is an objection easily
surmounted.
The "hardness" of water represents the weight of carbonate of lime, or its
equivalent of other mineral ingredients, found in 100,000 parts of water.
The average hardness of the Thames water delivered in London last year
was 19°.2; of the Kent Company's water 29°.4 ; and of the Colne
Valley Company's water 4°.5 only. The hardness of the waters is of
no consequence in respect of their fitness for drinking purposes: the
superiority of a soft water like that of the Colne Valley Company, however,
comes into play and becomes a matter of first importance in nearly