The Sun.
London, England, 1850-11-12 00:00:00

" SURFACE WATERS.

Ash-common 35
" IloIt•pond 24
Dippenhall... 35
" Whitemoor...
" Aldershot ...
" Canal Reading-road-bridge
" Thus we see that waters stand for purity in this diz-
xict in the following order:—
" 1. Spring issuing from pure sands.
" 2. Collections of rain water.
" 3. Water running through ordinary loamy soils.
" 4. Well waters.
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How great is the loss of capital and labour expended
on wells, which when made what has been done ? A
vast expense is incurred to dig a hole in the ground to
allow water to soak into impure from the mineral quali-
ties of the soil ; what water ?—that which fell origi-
nally soft and pure. and which might have been col
lected on roofs, or by drainage of cultivated lands and
led into a covered reservoir, and thence to the highest
room in the house. One gentleman with whom lam
acquainted spent from 3001 to 4001. in sinking a well
300 feet deep, whence he obtained water of a hardness
equal to that of London. 4001. would have drained
from 40 to 50 acres of his land and paid for a covered
reservoir, besides saving the labour of pumping and
carrying, the waste of the latter in the case of using 5;
gallons per day per house, amounting to a loss of three
days' labour of one person in a week. The improve-
ment of the land drained would alone have repaid the
outlay.
" A groat economy in having water laid -on to the
top of a house exists from the indolent propensities of
servants, should there be two supplies, one of hard
water and another of soft near the premises, and the
servants will, I have frequeetly found, to save trouble,
use the former for ail purposes, thus extravagantly
wasting their masters' tea and soap; the saving in the
consumption of which with soft water would soon have
paid the cost of laying pipes into every part of the house.
"I would point out the defects of seeraee reservoirs on
gathering grounds as now existing in some parrs of this
country. They collect the crude surface waters, always
liable to diseolouration and thickening tram dirt brought
in by heavy rains, to deterioration in taste, to hard-
ness from contact with the soil, as also by evapora-
tion; this last, however, being trifling as compared
with the first, as we have already shown. Compare
these results with the proposition of the board. After
the ground is once saturated, the rain-fall passes im-
mediately through a natural filter of sand into the
drainage pipes, which lead it away to storage reservoirs
lined with tiles to prevent the water acquiring the reiee-
ral qualities of the soil, hence to a covered reservoir in
the n, ighbourhood of its distribution, safe from the
noxious influence of the impure atmosphere of a city.
The impor,ance of covered reservoirs cannot be over-
rated w hen the evidence given by several eminent pro-
fessors of chymistry before the board is considered, al-
though little more than every day's experience is needed
to show that what is disagreeable on a small scale must
be very detrimental, often dangerous, in large volumes
of water. A tumbler of water cannot be exposed half
an hour without becoming warm, vapid, and badly
tasted; and from what cause? Simply because water
has an extraordinary capacity for absorbing the impuri-
ties of the atmosphere.
" Referring again to the plan of collecting rain-fall
by draining the sandy heaths, I question whether it
could in one case be carried out with advantage, namely,
on the higher levels; as, for instance, the crests of
the Fox Hills and Chobham Ridges, where the strata
of sand are of a very loose nature. I think that the
surface once broken through, the water would pass by
the pipes. The area on which this would happen is,
however, not very large. It is very desirable to ascer-
tain this point by trial works; a few acres drained
would satisfactorily settle an important question. The
same would occur in the lower levels were it not that
nature has abundantly provided a subsoil in the form of
a crust or pan about nine inches thick, composed of three
inches of closely-packed pebbles and sand resting upon
six inches of sandstone. This pan lies at a depth vary-
ing from one to three feet below the surface; in some
cases it is found beneath a few inches of sandy loam.
Tne pipes might be laid on the pebbles and sand in-
crusted together, which would hold the water. The pan
once broken through the water would, I fear, be lost for
ever. The cultivation of these heaths would eventually
repay a large portion of the expense of collecting a rain-
fall by drainage. Mr. Hewett, a most intelligent farmer
and land-curveyor, from whom I have obtained much
valuable information, assures me :thut where this pan
comes near enough to the surface to be broken through,
which is done at an expense of 81. or 101. per acre, and
when properly manured, the cultivation pays.
" The only disadvantage attending the board's scheme,
if to such an important matter it may be deemed so, is
the expense of the large lined storage reservoirs neces-
sary to contain a six weeks' or two months' supply for a
city of the giant proportion of London; otherwise the
system is unique in simplicity and perfect adaptation for
the purpose rtquired. So vivid was this impression on
my mind, that on developing the idea of supply from
springs, I conceived a method of adapting the principle
to my own case. Where the springs are large, I propose
to enclose them in brick or tiles, but when small and
numerous I would prefer to gather them in one stream
to be led away in pipes, but this must be effected on the
pure sand, and great care must be taken to avoid the
mixture of surfacr-washing. In the case when leading
away a stream of epringe it would be liable to discolora-
tion from heavy rams, I propose to provide a remedy
by preparing at the point of dive, s've from the
natural channel a new tel for a short distance at a
less inclination. The bed to he a trench with a
pipe at the bottom, and filled up with small
stones and sand, heather or heath being placed round
the pipe joints. The stre;:in being led on this new bed
will percolate into the pipe beneath. When the extent
of the ground above the springs would expose them to
be choked up by rubbish and dirt after a storm, I would
intercept she rain-fall in contour trenches with pipes tie-
' dernenth t hem also, and ley u branch to lead the water
away to the main. I have shown both these plans as
adapted in the case of Faruharn-hill, and a large addition
might thus be made to flow of the springs ii desirable.
‘• Hereafter I propose to detail my arrangements of
branch lines from the spring-heads, leading to mains
terminating on Wimbledon-common, giving also an esti-
mate of the expense of the entire scheineworks, compen-
sation to mills, Sec., alio some general infermeti in en
the collateral advantages of a pure soft water supply—
the results of some experiments I am making on the
action of sand as a flutes', and some qualitative analyses
of the springs.
" The annexed plan is that of Farnham-hill, reduced
from the Tithe Commission plan, and tested as to accu-
racy. The blue contour line represents the level of the
springs. I have gathered them together and gauged
their flow as accurately as in my power. Their daily
discharge is equal to 897,393 gallons.
" The area within the contour line is 571 acres. The
available rain-tall from 22.65 inches per annum; a mean
of 30 years' register at the Military College, Sandhurst,
allowing the usual deduction of 14 inches for evapora-
tion and absorption, is 279,858 gallons per day. The
difference then, 611,160 gallons, is the least figure in
favour of my assertion that the water in this hill is due
to rain-fall elsewhere, for the rain on this hill does not
percolate, but passes away.
"I assure the board, however, that a careful collection
of these springs would double their value, and produce
a daily discharge cf 1,794,786 gal'ons. This then leaves
a total of 1,514,928 gallons above the available rain-fall
on the hill, supposing it all to penetrate. The plan also
shows the hill drained above the springs on the principle
already alluded to. The section of toe pipes and their
outfall is calculated in proportion to the quantity of rain
likely to fall in the shortest time, according to the prin-
ciple laid down by Mr. Chadwick.
"In reference to my idea of the cause to which these
springs are due, I would mention that a notable instance
of the kind occurs in Ilong-K mg, an island mountain of
not 25 miles in circumference at its base, and of 1,000 or
1,200 feet elevation above the level of the sea. The
quantity of water supplied from springs on the top of
this mountain is notoriously far be} and its rain-fall,
which latter, from the declivity of the other groune,
is at once discharged into the sea, as all who have been
there are well aware of. The shore of the mainland is
net further than two miles and a half, but the range it
mountains of equal and higher elevation, and which
furnish the supply, are at a distance of upwards of ten
miles. The rain-fall cannot find its way again after
percolation to the surface, and is necessitated to find its
!evel by crossing the sea and rising through the fissures
of the granite formation of Hong-Kong. The springs
are rarely known to be affected in quaatity oven after a
three months' drought in the island,
tithe thermometer
often at 88 degrees and upwards in the shade,
" The advantages I propose to derma fro permanent