174 
THE PURIFICATION OF WATER. 
East London Company’s water, col¬ 
lected August 1, 186G . . . , 
East London Company’s water, col¬ 
lected July 1, 18GG . 
East London Company’s v.’ater, ave¬ 
rage of one year. 
“It is the amount of organic matter contained in this water which is of especial im¬ 
portance in connection with the outbreak of cholera in the district supplied by this com¬ 
pany. The above results that, in this respect, the water supplied on August 1, is con¬ 
siderably better than that supplied on July 1, when the amount of this ingredient was 
markedly above the average. Chemical analysis, therefore, although it sliows a larger 
quantity of organic matter than ought to bo contained in water used for drinking pur¬ 
poses, does not reveal any exceptional degree of pollution in this water. It must be 
borne in mind, however, that chemical investigation is utterly unable to detect the pre¬ 
sence of choleraic poison amongst the organic impurities of water, and there can be no 
doubt that this poison may be present in quantity fatal to the consumer, though far too 
minute to be detected by the most delicate chemical research. 
“ It is thus that the occurrence of cases of cholera, or of choleraic diarrhoea, upon the 
banks of any of the streams from which the water-supply of London is so largely de¬ 
rived, may at any moment diffuse this poison over large areas of the metropolis. For 
the prevention of such a catastrophe there is a method which deserves considerable con¬ 
fidence. In my last three monthly reports to you on the metropolitan waters I have 
shown that filtration through animal charcoal (bone-black) removes practically the whole 
of the organic matter from the New Eiver water; and in numerous other experiments I 
have ascertained that this process is equally efficient even when applied to the foul 
waters of ponds and ditches. I have also proved that its action continues unimpaired 
for three months, and will probably last for a year, even when very large volumes of 
water are passed through it. Animal charcoal alone has this power, vegetable charcoal 
being perfectly inert. 
“ I would, therefore, most earnestly recommend that during the prevalence of cholera 
the whole of the water supplied to the metropolis should be passed through animal char¬ 
coal immediately before transmission to consumers from the reservoirs of the respective 
companies. For this purpose 300 tons of bone-black, in the condition in which it is used 
by sugar refiners, would be required to purify the total supply of the Metropolis, as I 
rind that water passed at the rate of 1,000,000 gallons in twenty-four hours through 
three tons of bone-black, is completely purified. This operation, even when performed 
upon the water-supply of London (100,000,000 gallons daily), would be neither for¬ 
midable nor expensive. Three or four days would suffice to fix the necessary filtering 
boxes, whilst the animal charcoal, being an article which is now manufactured on a very 
large scale, can be had on the shortest notice. It is scarcely necessary to add that the 
water should be passed through the animal charcoal after it has undergone the usual 
process of filtration.—I have, etc., “ E. Fbankland.” 
In another letter, addressed to the Secretary of the East London Water-Works Com¬ 
pany, Dr. Frankland has recommended the immediate use of permanganate of potash to 
be applied after filtration, and immediately before the water is transmitted to the con¬ 
sumer. 
EARLY CLOSING. 
The following notice has been circulated by some of the chemists at the west end of 
London:—“This establishment will close every evening at eight o’clock. Families 
are most respectfully solicited to send their orders as early as convenient prior to this 
hour.” 
Solid matter 
in 100,000 
parts. 
Organic and 
other volatile 
matter in 
100,000 parts. 
Oxygen re- 
qxiired to oxi¬ 
dize the or¬ 
ganic matter. 
Degree of 
hardness. 
Dej?. 
2GT4 
1-44 
•0328 
17-7 
24-38 
1-94 
•0344 
16-G 
27-98 
1-G2 
•0504 
21-12 
