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Having thus summarised Dr. Frankland's views—reproducing
in the consumers' interests, as in duty bound, the strictures on
river water of what may be considered the official report, it is
only fair to state that river water is not without its defenders and
advocates. Among these, Dr. Meymott Tidy stands conspicuous,
and he has summed up all, perhaps, that can be said in its favour
in a paper read before the Chemical Society in May, 1880, and
printed in the Society's transactions. He contends that dangerous
organic matter is rapidly destroyed, through the operation of
natural laws, when introduced into running streams, and gives
numerous experiments to prove his point. "Reviewing all the
facts," he submits—
1. "That when sewage is discharged into running water, provided the primary
dilution of the sewage with pure water is sufficient, after the run of a few miles,
the precise distance of travel being dependent on several conditions, the removal
of the whole of the organic impurity will be effected.
2. "That whatever may be the actual cause of certain diseases, i.e., whether
germs or chemical poisons, the materies morbi which finds its way into the river at
the sewage outfall, is destroyed together with the organic impurity after a certain
flow."
During the past year, moreover, the water supplied by the
several Companies has been subjected to a daily examination by
Messrs. Crookes, Odling and Tidy, on behalf of the Companies, and
the results of their examinations have been collected and published
in the form of an annual report, which they have addressed to the
President of the Local Government Board. From this report
I extract the following notes. The writers say that the water,
as a rule, is efficiently filtered, and that the "suspended matter,"
almost entirely of the nature of clay and sand, on the worst days,
when the water was recorded as "turbid," averaged considerably
less than one grain per gallon. The organic carbon may be taken
as a trustworthy index of the organic matter in the water, the
amount of it being, as a rule, contrary to popular, but not to scientific,
opinion, exceedingly small, never exceeding the 1-1,000th of a
per cent. The water is well aerated, and contains in solution very
nearly the full quantity of free oxygen that it is possible for water
to dissolve, a fact of great importance as an evidence of the
absence either of putrescent or putrescible matter. As for the
mineral matter held in solution—that which gives to water its
"hardness," it consists mainly of the carbonates of the alkaline