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107
But it is also evident that none of the three Water Companies
taking their supply from the Thames provide so pure a water as the
New River and the Kent Company, and it is a question whether
taking water from a polluted source they can so filter it as to prevent
it being a source of danger to the consumer.
Apparently they cannot do so, as your analyst, Mr. C. E. Cassal,
points out that the words "anomaly" and "abnormality" are terms
constantly used in the reports made by the Companies' analysts
to explain adverse chemical results. The principal explanations
offered to account for these "anomalies" and "abnormalities"
are:—
(a) A sudden increase of (so-called) harmless microbes took place
in all the Companies' waters. Cause unexplained.
(b) Defective filters.
(c) Temporary defect in a filter.
(d) A purely local cause in one of the filters, and so on.
It is thus admitted by the Companies that absolute reliance is
not to be placed in the filters, and even when working in their usual
way adequate purification of the water is not secured. The provision
of large subsidence reservoirs is probably a very important factor in
obtaining greater security, but still, so long as the source of supply
is polluted, there must always be the risk of "the temporary defect"
in the filter.
That risk may be probably a small one, but if a defect occurs at
a moment when the typhoid or cholera organism is in the water, the
result will be serious.
The New River Company has supplied water of such superior
quality that I viewed with some uneasiness the scheme of intercommunication
which was eutered into between the Metropolitan
Companies a few years ago in order to assist the East London
Company, and I wrote to the New River Company on the subject in
1899, pointing out that by mixing Thames water from the Grand
Junction and West Middlesex Companies with their own, they were
lowering its quality and adding an element of danger.
The Company, in reply, relied on the Report of the Royal
Commission that there was no evidence of danger. I find that
during 1901 the New River Company supplied the East London
Company during part of July, August, and September, and in turn
received from the Grand Junction and West Middlesex Companies,
in July, an amount which, if spread equally over the month,
averaged 4,965,313 gallons daily. In August 7,749,481 gallons
daily, and in September 3,726,195 gallons daily. The effect of this