The Sun.
London, England, 1867-04-04 00:00:00

The Water Supply of London.

At the Royal Institution on Friday evening the
water supply of London was the subject of a lecture
by Professor Frankland. He first pointed out the
importance of having a good supply of water by re-
ferring to the statistics of cholera, showing that the
death rate caused by it in London was proportioned
to the impurity of the water in each district.
Thus in 1854 the rate of mortality in those
parts that were supplied with water from the
Thames taken above Kew was 8 in 10,000 ;
in the parts supplied from the river at
Hammersmith it was 17 in 10,000 ; and where the
water supply was derived from the river lower down
than Hammersmith the death rate from cholera was
as high as 163 in 10,000. All the water now supplied
to London from the river Thames was taken above
Teddington Lock, and was in a comparative state
of purity. In the eastern part of London, which
was supplied from a reservoir at Old Ford below
high-water mark, the death-rate from cholera
had been very high. in consequence of the im-
proved supply of water to London, the death rate
from cholera last year at the West-end was from
2 to 12 in 10,000 ; while at the East-end of London,
where the water supply had not been improved,
it amounted to as much as from 63 to 111 in 10,000.
London is now supplied with water by nine com-
panies, with a quantity amounting daily to 108
million gallons, which is more than double the
supply in 1850. Five of the companies obtain the
water from the river Thames above Teddington
Lock, two from the New River and the Lea, and
two artesian wells. Different plans have been pro-
, posed for supplying London with water from sources
of greater purity, one of which is to obtain it from
Bala Lake, and the surrounding district of North
Wales, at a distance of 183 miles from London
—the cost of the undertaking being estimated
at £8,600,000. From that source it is anticipated
that 200 millions of gallons might be supplied
to London daily. Another plan is to drive the water
from Cumberland Lakes, at a distance of 240 miles,
but that undertaking would involve the construction
of long tunnels, and the estimated cost i5£12,200,000.
The quantity to be obtained from that source would
be 200 millions of gallons daily for the metropolis,
and 50 millions of gallons for distribution to towns
on the route. The water rate on house property for
the supply from lhe first-named source would be
ls. Id. in the pound, which, high as it may seem, is
considerably less than the general cost of the
present water supply. The quality of the water
from North Wales and from Cumberland is
nearly the same. The other plans for drawing
water from a distance have not been sufficiently
matured to deserve consideration. With respect to
the purity of the present water supply, Dr. Frank-
land stated that th; quantity of solid matter varies
from 28 to 39 parts in 100,000. The test by per-
manganate of potass, which has hitherto been relied
upon for detecting the presence of organic matter in
water, has been found to be very fallacious, as was
shown by several experiments. The two principal
impurities in water consist of organic matter, and
the salts of lime cud magnesia, which produce what
is called " hardness." The remarkable fact was
stated by Dr. Frankland that no sewage matter
is detectable in the water derived from the
Thames, though it receive the drainage of many
large towns before it reaches Teddington Lock. He
attributed this fact to the absorption of oxygen
from the atmosfhere, but practical men who are

not chem'sts may be inclined to attribute it most
probably to the agency of the fish which abound in
the Thames, and are the most active river scaven-
gers. As it will be at least seven years before either
of the proposed schemes for supplying London with
water from adistance can be carried into execution,
Dr. Frankland suggested that, for the purpose of
rendering the present supply more pure, large quan-
tities of animal charcoal should be employed in its
filtration. The lecture was illustrated by diagrams
and numerous experiments.