The Sun.
London, England, 1841-01-01 00:00:00

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PRICE sd.

divested of any covering which could intercept ;the pas-
sage of the moisture; being not only extremely porous,
but also full of fissures in every direction, a very rapid ab-
sorption takes place, and we accordingly find that there are
but few streams carrying off the surplus surface water,
and that these are in9igniticant, and indeed, many of them
dry during the greater part of the year. The rapidity with
which the water finds its way into the bowels of the earth
also, in a great measure, prevents evaporation, and we are
therefore justified in assuming that the quantity which de-
scends upon the surface of the chalk finds its way, with
very slight diminution, into the fissures below. The lower
beds of the cretaceous group, and the gault which imme-
diately succeeds it, again presents en impermeable stratum
of clay, causing the water to accumulate through the
lower regions of the more porous chalk. An enormous na-
tural reservoir has thus been formed, and the level up to
which it may be considered as quite full of water is the
lowest point where it can find a vent and overflow; there-
fore, as the chalk communicates under the coasts of Nor-
folk, Suffolk, and Essex with the ocean, this level, in the
present case, may be considered to be the same as the mean
height of the sea.
That there is, however, an eY'ensive accumulation of
water above this level will be obvious, when it is considered
that the friction, which from the nature of the small fis-
sures and pores must exist, will necessarily prevent the
water from exerting rapidly its hydrostatic pressure, and as
for this reason it cannot flow off with sufficient velocity,
the higher parts of the chalk belt which surround the Lon-
don clay being saturated, will allow its escape to the sur-
face wherever it can find a nearer and mote ready vent
than its subterraneous one.

The greater or lesser facility which, from lines of fis-
sures, soft strata, and pores, the water may encounter in
flowing towards the centre of the basin, will also govern
its surface, and cause it to assume an inclination, the angle
of which will represent the friction; and in this manner
ti:e may readily a'count for the different levels, which
loud

to standin welts,
The foregoing' remarks will now enable me, l'think, to
show that the proposal of perforating the tertiary clays
for the purpose of obtaining water for the general supply
of the inhabitants of London would not have beeu attended.
with the advantages which at, first signt it "would appear
'possessed of. It may, indeed, be urged that a reference
to the section shows us London situated nearly over the
centre of the basin to which it gives its name, and that we
may consequently infer that walls sunk through cocero'
strata into the chalk will derive their supply immediately
from that portico where the greatest accumulation of slim'
exists by my own showing. But it will he found that
this very circumstance throws a material difficulty in the
way of any attempt. to supply the inhabitants of the metro-
polis from this source, and one which has been found fre-
quently confirmed, when private individuals have sunk
deep wells in London. ' The objection is, that whenever
a large quantity is extracted, the wells in the vicinity,
which derive their water from the same strata, are very
sensibly affected, and for this reason, that although a con-
stant supply will always, as I have shown, find its way
' down, to take the place of whatever water we may pump
away, this cannot flow in so quickly from the obstructions
of the stratification, but that the level, for some distance
round this focus, will be temporarily reduced. In other
parts of the disti ict, as will be readily understood, this
would not be the case; or if so, at least in an inferior de-
gree, as a well would not here derive its share from every
side of the basin at once, but only from that portion situ-
ated immediately above it. At Watford, for instapee, a
well would only be fed from the chalk which intervenes
between that place end the great outcropping Chiltern
Ridge, and so in any other part of the belt. I may also here
add, that the sheet of water in the deeper part of the!chalk
can only be affected to an insensible degree by such a
well, which at most would merely deprive it of the supply
front a very trifling part of the great circle which every-
where else would remain untouched.

The Company which had been based on the Artesian
project probably soon obtained facts which proved that, their
proposal could not be established without such interte-
eence with private interests as, they undeubtedle foresaw,
would have great weight with the House of Commons;
and they must also have taken into account the expense of
forcing the requisite quantity of water to the elevation no
cessary for the high services, in addition to which, it must
be borne in mind, that after perforating,, say 200 feet of
clay, the water under London by no means rises to the
surface. As might have been readily foreseen this idea
was, after some tine, abandoned, and it is not surprising
that its originator, Mr. E. Paton, should have turned his
attention to other endeavours.
The abundance of the springs which overflow into the
Culet valley, above Watford, and the apparent purity of the
water, had long attracted his attention, and now led him, in
connection with some other gentlemen, to make various ex-
periments' to ascertain whether a sufficient quantity for the
dereends of the metropolis could be obtained in that neigh-
buurhiseeel. at a sme.l depth beneath the surface; and wiiether
this taignt be effected without injuring the existing jute-
rests in the vicinity. \Veen it was found that the tesult
more than confirmed their moat sanguine wishes, I was re.
rated to examine whether the experiments were well
Plan into effect.
I had for a length of time been acquainted with the va-
rious proposals which have been submitted to the public,
and was aware of the objections which could with justice
he urged against them. It was, therefore, not without
pleasure that I undertook the examination of a plan which
I at once saw might be possessed of advantages which
were not before contemplated.
It will be my endeavour, in the remainder of this report,
to shots how far the hope of obtaining the necessary quan-
tity of water at Watford is well founded; to describe the
experiments which have beet/ made for the purpose of ac-
quiring practical data to explain the proposed method of
procuring the water and conveying it to London ; and,
lastly, to submit such remarks as will enable you, in my
opinion, to present the project before Parliameut with a
confident reliance that is cannot but deserve its attention
and support.
As I have already described at some length the geologi-
cal features of the country surrounding London, I ant not
called upon to add much to my former explanations on this
head, and shall confine myself here to stating, that, as re-
gards the more immediate object now in view, we may look
upon the Colne valley, as marking in a great part of its
length on the one side the escarpment caused by the out
crop of the plastic clay, whilst on the other the country
rises gradually to the north-western boundary of the chalk
strata, the Chiltern Ridge.
An attempt to fix positive quantities, by any line of
argument,is naturally attended witleconsiderablechfficulty ;
nevertheless, the following considerations will give some
idea of the volume of water that can be derived from the
chalk of the Colne valley.
The surface of country which has its drainage into the
Verularn and Colne, above Watford, may be taken at
113.4 square miles. If then we assume that the annual
fall of rain amounts to twenty inches, which you will find
a low average, the result will be 141 millions of cubic feet
of water per twenty-four hours falling on the surface. Of
this quantity Mr. Telford found that the Colne carried off
at Watford thirty cubic feet per second, or about two
millions and a half per twenty-four hours; as this was,
however, in a dry season, it will be safer to assume Dr.
Thompson's calculations with respect to the annual quan-
tity of water flowing off by streams and springs, which he
was led to fix at four inches, and this would give us for
the area drained by the Colnc nut quite three millions per
day.
There remain then eleven millions and a half of cubic feet
per twenty-four hours either to be again evaporated, or to
fuel their way into the earth. In an earlier pert of this re-
port you will remember that I showed that the porous na-
ture of the soil in a chalk district prevents the evaporation
to a great extent ; nevertheless, if we assume that, with
the portion which eaters into animal and vegetable life,
one-third of the entire quantity falling disappears in this
manner, we still shall have upwards of six millions and a
half of cubic feet, or forty-two millions of gallons per
twenty-four hours, supplying the sheet of water under that
portion of the chalk surface.
Mr. Telford's examination of the body of water flowing
off by the Colue river, having been made at a period of
uausual drought, when the_surface water might be con-
sidered to have nearly disappeared, we shall, I think, be
correct in assuming that two millions at least of the quan-
tity he measured had issued from springs. In order,
therefore, to represent the total subterranean flow, we
should add these two millions to the former oi. These,
indeed, would seem no part of the supply to the deep, but
would designate that supply which, as has been already ex-
plained, cannot find its way to the lower depths, owing to
friction and other impediments, and therefore reeks a
readier vent at a higher level.
It was important that this should be set in its proper
light, as the evident inference we may draw is, that we
cannot, by pumping from a lower level a quantity small in
comparison to the accumulation of water, produce any visi-
ble effect upon the springs which feed the Colne.
I am quite confident that my views as regards the manner
in which the water finds its way into the strata of the chalk
will not for a moment be called in doubt by any scientific
person, but that which may by such a one be considered
in the light of a received axiom, and proved by numerous
corresponding facts bearing thereon, with which he will be
already acquainted, will require more lengthened demon-
stration to the general public, with whom an appeal to
experience will have far greater weight than any abstract
reasoning. To these, then, the experiments which have
been made will afford far more conviction than any argu-
ment, however well grounded.
The alluvial bed, which covers the bottom of the Colne
valley, rather exceeds 20 feet in thickness, after which we
reach the chalk ; proceeding about five feet lower, abun-
dant springs of water are encountered, which increase in
magnitude and force as we continue to descend.
It was, therefore, in the first place necessary to ascer-
tain that these did not derive their supply directly front the
river, which, had it been the case, would have affected the
various mills in the vicinity ; and it was also desirable to
have direct proof of the quantity which might be calcu-
lated on being obtained. In order to obtain positive evi-
deuce on both these points, a well was sunk in Bushey
Hall meadows, near the Colne, to a depth of about 31 feet.
Two small steam-engines were then set up temporarily,
for the purpose of workiaigthfaoulrenpgutmhposf,
strokeof o
whichf
3 two (
in
c werehes,
13 inches in diameter, with

The land requisite for carrying into effect these expe-
riments was kindly and most hocrally granted by Edward
Marjoribauks, Esq., who stated, when he gave his consent,
"that the health of the inhabitants of London was para-
mount to every other consideration." The Committee for
this, and other acts of kindness, are most deeply indebted
to that gentleman.