The Sun.
London, England, 1840-12-31 00:00:00

cater above this level will be obvious, when it is considered
.hat the friction, which from the nature of the small fif-
.ures and pores must exist, will necessarily prevent the
water from exerting rapidly its hydrostatic pressure, and as
!or this reason it cannot flow off with sufficient velocity,
the higher parts of the chalk belt which surround the Lon-
lon clay heing saturated, will allow its escape to the sur-
face wherever it can find a nearer and mole ready vent
than its snbtcrraneous one.

The greater or lesser facility which, from lines of fis-
sures, soft strata, and pores, the water may encounter in
lowing towards the centre of the basin, will also govern
is surface, and cause it to assume an inclination, the angle
if which will represent the friction; and in this manner
;re may readily account for the different levels, which
often appear anomalous, at which the water will be found
;.o stand in wells.
The foregoing remarks will now enable me, I think, to
show that the proposal of perforating the tertiary clays
,or 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 sight it would appear
possessed of. It may, indeed, be urged that a reference
,o the section shows us London situated nearly over the
eantre of the basin to which it gives its name, and that we
may consequently infer that wells sunk through cocene
strata into the chalk will derive their supply immediately
from that portico where the greatest accumulation of water
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
ieep wells in London. The ohjsetien is, that whenever
A large quantity is extracted, the wells in the vicinity,
which derive their water from the same strata, arc very
sensibly affected, and for this reason, that although a con-
stant supply will always, as I have shown, find its way
town, to take the place of whatever water we may pump
'way, 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
Jails of the disHet, as ;CIA be readily understood, this
vould not be the case; or if so, at. least in an inferior de-
4ree, as a well would not here derive its share from every
,ide of the basin at once, but only from that portion situ-
ited immediately above it. At Watford, for instance, a
pit would only be fed from the chalk which intervenes
'between that place and the great outcropping Chiltern
Ridge, and so in any other part of the belt. I may also here
idd, that the sheet of water in the deeper part of the chalk
•an only be affected to an insensible degree by such a
sell, which at most would merely deprive it of the supply
from a very triflirg part of the great circle which every-
where else would remain untouched.

The Company which had been based on the Artesian
tiroject probably soon obtained facts which proved that their
proposal could not be established without such interfe-
rence with private interests as, they undoubtedly feresaw,
wotild 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 ne
cessary for the high services, in addition to which, it must
tie 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 time, 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
Colne 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
demands of the metropolis could be obtained in that neigh-
bourhood. at a small depth beneath the surface ; arid whether
this might be effeCted without injuring the existing inte-
i rests in the vicinity. When it was found that the result
I more than confirmed their most sanguine wishes, I was re-
quested to examine whether the experiments were well
grounded, and to advise as to the means of carrying the
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 show how far the hope of obtaining the necessary quan-
tity of water at Watford is well founded ; to describe the
experiments which have been 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 Parliament wiLli a
confident reliance that it cannot but deserve its attention
and support.
As I have already described at some length the geologi-
cal features of the country surrounding London, 1 am not
called upon to add much to my former explanations on this
head, and shall confine myselt 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 :he 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
argurnent,is naturally attended with considerabledifficulty ;
nevertheless, the follewit.g 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
Verulam and Collie, above Watford, may be taken at
1131 square miles. If then we assume that the annual
fall of rain am runts to twenty inches, which you will find
a low average, the result will be I -ti 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 pith respect to the annual quan-
tity of water flowing off by sties:us and springs, which he
was led to fix at four inches, and this would give us for
the area 'rained by the Colne nut quite three millions per
day.
There remain then eleven millions and a half of cubie‘gt
per twenty-four hours either to be again evaporated, or to
find their way into the earth. In an earlier part 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 caters into animal and vegetable lite,
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 Colne river, having been made at a period of
unusual 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 6,k. 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 arid other impediments, and therefore seeks 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 Colic.
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, wills 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 arc 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 from 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-
dence on both these points, a well was sunk in Bushey
Hall meadows, near the Colne, to a depth of about 34 feet.
Two small steam-engines were then set up temporarily,
for the pul-pose of working four pumps, of which two were
13 inches in diameter, with a length of stroke of 30 inches,
and the others were 13. inches in diameter, with a 36-inch
stroke. One of the engines might be calculated to pro-
duce from 27 to 30 strokes of the smaller pumps per mi
nute, the other betweea 17 and 20 strokes of the larger
pumps. The water of the well was now repeatedly
pumped out, as low as the power of the engines admitted,
and the height of the Collie at those times carefully noted,
and it soon became obvious that the height of the springs
could in no degree be said to affect the level of the
river, thus showing that all direct cominueication between
the two might be considered ascot cif by a bed of puddle, or
clay. The next object of inquiry was, as to the supply
which a well might be expected to yield, and the result
of a careful experiment, made under my direction, and
confirming those previously conducted by Mr. Paton, sa-
tisfied me, that after the water had for twenty-four hours
been kept at the lowest level to which the power of the
pumps would reduce it (about I %seedy-six feel below its
surtixe when Undi'clurbed ), it rose in the well with a velo-
city equal to 2 02 feet. per second, thus yielding 17-I,alo
cubic feet, or 1,091,000 gallons per 21 hours. As this was
obtained in a well, the bottom of which was only 12 feet 6
inches diameter, and us direct proofs had been obt.sincd by
borings, that below the 34 feet reached in the well
there was a constant recurrence of large springs, giving
evidence that the water rapidly increased with the
depth, which when 80 feet were obtained, became so pro-
digiously plentiful as to set all temporary means of over-
coming it at defiance, and precluded all possibility of hav-
ing recourse to it for the mere put pose of an exporiment,
I thought it quite unnecessary to seek further pvuol.; that
1 a sufficient supply for all requisite pi po.ies iiiiiit wills
facility he obutirred.
It would be premature to give, in the present stage of
the proceedings, a detailed account of the arrangements I
propose making, for augmenting the Quantity to an arle-
plate extent ; au I it may he sufficient to state here, that

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

EVENING EDITION.
I have not the slightest doubt, that by sinking a deep yell,
and extending tunnels or drifts in the proper direction from
its bottom, the necessary supply will be fully accomplished.
Being also convinced that the water fiLering through the
chalk might be considered as entirely divested of all im-
purities, held in mechanical suspension, of which, indeed,
there was abundant ocular demonstration (as it was so
beautifully transparent as to admit of the bottom of the
well being seer' when the water was upwards of 30 feet
deep), I at once turned my attention to the best means
,of
conveying it to London.
The principal difficulty which intervenes is the ridge
formed by the escarpment at the outcroieof the plastic and
London clays, which Mr. Telford, in his proposal to bring
the water of the Verulam stream to London, had content
plated perforating by a tunnel three and a half inilei't
length. My connection with the London and Birmingham
Railway has placed me in possession of facts which con-
vince me that at the level at which Mr. Telford would
have traversed sonic of the beds of chalk, and tie whole
of the plastic clay, he would have met with very great
difficulty, in consequence of water. For this reason I
propose, on leaving the Colne valley, that before en-
tering the ridge which separates it from the district
draining into the Brent, the water should
be forced to a height of :50 feet above its original level, at
which elevation vs e get rid ut the difficulties of the plastic
elay, ss we only traverse its upper extremity, where no
water has yet accumulated. Tlie length ot the tunnel is
also considerably reduced.
I have pm ferred adopting a line which is materially
shorter than Mr. Telford's, as, with the exception of the
said tunnel, two and a half miles in length, no difficulty of
any kind is encountered. Immediately on the water re-
issaiing into the open air on the side of Brocklcy-hill, I
propose forming a reservoir to contain three days' supply
of watt r, \xi h a sufficient head to admit of a main being
laid hence, and conveyed (in order to avoid all or position
from landowners) front the town of Edgcware to Oxford-
street, along the side of the road itself; thereby also faci-
litating the laying of the main, and rendering all the
works of any magnitude, as earthworkF, aqueducts, &c.,tm-
necessary. The level of the reservoir witl lastly be such,
that the highest service can be given, and, indeed, a part
of the town which none of the present Compaides can sup-
ply, will be included within its range.
I trust I have now said enough to convince an unbiassed
person that there exists no difficulty, both in obtaining a
supply of good water from the springs of the chalk, near
Watford, and in conveviug it thence to London. I must,
however, impress you here with the necessity of enforcing my
arguments with as numerous a body of facts as can be col-
lected, and I would therefore recommend that, previously
to the meeting of Parliament, I should be authorised to
collect such information respecting the quantity, nature, end
quality ot the wells in every ;eta of the chalk circle which
surrounds London, as will bear practically on the subject.
This ri4ht then be embodied in a second Fart or appendix
to this n port, to be submitted to those who, being unac-
quainted with geological phenomena, may consequently he-
sitate in adoptlng views which others, already scientifically
acquainted with the subject, will r ot for a moment call in
doubt.
__ _

In concluding, I may be allowed to cast a retrospective
glance at the advantages held out by the project I have
been called upon to examine. These, then, consist in its
being proposed to use spring water, already naturally fil-
tered, in preference to that which has drained a portion
of the earth's surface ; in making use of that enormous -
servoir which nature has supplied us with in the chalk,
and effecting this at a spot where no exiting interests enn
be injured ; and in the selection of such a situation as ena-
bles us to convey the supply to London with facility and
economy, and at a sufficient elevation to sa:isfy the de-
mands of even the highest part of the metropolis.
I have the honour to be, Gentlemen,
Your obedient servant,
ROBERT STEPHENSON.
London, Dcc. 16.

SOCIETY FOR THE DIFFUSION

OF USEFUL KNOWLEDGE.

In consequence of a requisition this day sent to the
Chairman, I am directed by him to request the favour
of your attendance at n special meeting of the General
Committee here, on Wednesday next, the :30th inst.,
at four o'clock precisely, to consider the following

motion
It is expedient to amend the 14th by-law of the So-
ciety, by inserting therein the words and Treasurer'
between the words • Vice-Chairman' and • shall be an-
nually elected,' and again between the words ' Vice-
Chairman'and of a previous year?*
" It is also expedient that in the year 1841 the office
of Treasurer should he declared vacant, and the Corn-
mittee should proceed to fill up the same at the meeting
at which, according to the 37th by-law, the proposed
alteration shall be confirmed."
THOMAS COATES.
59, Lincoln's-Inn-Fields, Dec. '2.3,1840.

The CHAIRMAN has this day received the following
ether _ _

'• My Lord—Feeling, in consrquence of a division
of sentiment existing in the London General Committee
of the Society for tho Diffusion of Useful Knowledge,
that I should not be able again to meet it with that
cordiality which has hitherto invariably marked my
intercourse with its members, collectively and individu-

ally, and has proved my only requital for fifteen years
of zealous devotion of time to the interests of the So-
ciety, and to the duties of the office of Treasurer which
1 have during that. period held ; I beg leave to tender
my resignation of that office, and to request that your
Lordship will be pleased to convene a special general
meeting of the Committee to accept such re,ignation.
" I have the honour to be, my Lord,
" Your Lordship's very obedient servant.
" WILLIAM TOOKE.
" Russell-square, Dec. 28, 1840."
Mr. Tooke's letter will be taken into consideration
at the meeting on Wednesday, the 6th of January.
THOMAS COATES.

1.)9, Lincoln's Inn-fields, Dec. 28, 1840.
The following will be the 14th by-law, if the proposed
alteration is adopted. The amendment is indicated by
italics :
" X IV. The Committee shall supply vacancies in the
offices of Chairman, Vice- Chairman, and Treasurer, by
ballot, out of their own body. The Vice-Chairman and
Treasurer shall be annually elected by ballot, at the ordi-
nary monthly meeting in February, out of the members
nominated at some previous meeting, and the Vice-Chair-
man and Treasurer of a previous year shall be re-eligible
without previous notice."