Transcription:
Robert Underwood Johnson 2. demonstrated that the storage of water for a period of time has the effect of purifying it. The
large storage reservoirs used in London were constructed for the purpose of conserving water when it was abundant against
the time of relative scarcity, and Doctor Houston discovered that this storage reduces the number of bacteria of all sorts,
devitalizes the microbes of water borne diseases, reduces the amount of suspended matter and has a tendency to lengthen the
life of the filters. The storage of raw water antecedent to filtration enables him now to supply a potable water of a purity
which Satisfies the most exacting scientific tests. . The water board, therefore, has adopted what is known as the Staine's
Reservoirs Extension Schemes for the provision of additional reservoirs in the valley of the Thames. In this chain of reservoirs
the raw water will be taken in and decanted from one reservoir to the other, and finally be filtered. Calculations already
made show that the water so impounded will last until 1941, with an estimated population of twelve millions of people. She
advantages over the Wales scheme - which is such a one as you are opposing in the Yosemite - are overwhelming. The construction
of conduits of maximum capacity for maximum future supply, of course, would be tremendously expensive, whereas reservoirs
and filters can be constructed by units,- we do that here, and as need arises now units may be added. If you care to know
more about this whole subject, I am sure that If you were to write to the Metropolitan Water Board at the central office,
Savoy Court, Strand, W. C., London, they could toll you all about it. She clerk there is Mr. A. B. Pilling, F. C. I. S., and
the bacteriological expert is Doctor A. C. Houston, M. B. D. Sc., He may be addressed at 20 Nottingham Place, West, Yours
very sincerely, (Signed) Brand Whitlock.06331