London's Pulse: Medical Officer of Health reports 1848-1972
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Hints from the Health Department. Leaflet from the archive of the Society of Medical Officers of Health. Credit: Wellcome Collection, London
Kensington 1885
[Report of the Medical Officer of Health for Kensington]
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143
practically identical, but the fluctuations in temperature, according to
the season of the year, are much more marked in river than in deepwell
water. The latter remains of an agreeable coolness in the hottest
months, whilst the former becomes unpleasantly warm and unpalatable.
The range of temperature 'in the water of the Thames, as delivered by
five of the Companies last year, amounted to 33°.5 Fahr., viz., from
37°.0 in January to 70°.5 in July. The deep-well water furnished by
the Kent Company varied in temperature from 53°.6 in January,
February, and November to 58°.1 in June; range of 4°.5 only.
The transparency or otherwise of water is ascertained by its appearance in a tube two feet in length, and is expressed in arbitrary terms, as in the following table, which shows the degree of efficiency of filtration of Thames water as supplied by the Companies in this parish, and indicates a great improvement over former years, the examinations being made monthly:—
| Name of Company. | When clear and transparent. | Number of Occasions. | When very turbid. | |
|---|---|---|---|---|
| When slightly turbid. | When turbid. | |||
| Chelsea | 12 | 0 | 0 | 0 |
| West Middlesex | 12 | 0 | 0 | |
| Grand Junction | 11 | 0 | 0 | |
In a former report Dr. Frankland observed that "there is nothing which
exhibits more strikingly the greatly increased care and attention which
is bestowed upon the water supply of the Metropolis, by the various
companies to whom the supply is entrusted, than the marked improvement
in transparency: for the turbidity of the water is the only
factor over which they have complete control, depending, as it does
exclusively, upon the storage capacity and filtering appliances which
each water company has at its disposal."
The importance of long storage prior to distribution is considerable. The
amount of "combined nitrogen," Dr. Frankland states, "constitutes
the whole evidence exhibited by the various waters, of the nitrogenous
organic substances which they have in the past received, as well as of
those which they still retained at the time when the analyses were
made. In river waters the quantity of this total combined nitrogen
undergoes considerable reduction during the summer months, in consequence
of the vegetable life then active in these waters." "The
progressive reduction which has taken place in the amount of combined
nitrogen in the Thames supply is, in all probability, chiefly due
to the longer period of storage to which the water has of late years
generally been subjected before distribution, for during very prolonged
storage in natural lakes the inorganic combined nitrogen almost
entirely disappears."
The organic substances are "unobjectionable as regards their absolute
amount," but must be "viewed with suspicion," seeing that the river
receives, above the intakes of the companies, "more or less animal