Star.
London, England, 1826-10-10 00:00:00

THAMES TUNNEL

This singular and extraordinary andettaking is making
topid progress towards its completion, and there seems
every probability of ultimate success. The following is
a brief outline of the present state of the works :
The communication with the spot where the working
people are employed is by means of a shaft, 70 feet in
depth, 90 fe,t in diameter, and 150 in circumference, to
which vi,itots descend by means of a winding staircase.
11.4 art ana,ement is only of a temporary nature, and it
is intended, on the completion of the undertaking, to
form another shaft of a similar construction, but of
much larger dimensions, as a carriage-way. The dia-
meter of this shaft will be 200 felt, which, from the
base to the surface of the earth, will still leave a descent
of about 60 feet. This ascent, however, will be so con-
structed as not to create any considerable difficulty to
the carriage of heavy bnrthens.
The apparatus by which the work is carried on, is by
means of a cast-iron shield, which is under the controul
of a lever, in which there are 36 boxes, which can either
be moved singly or jointly, at pleasure, in which the
excavators perform their operations. There are three
tiers of them, and when the propelling power is called
into action, they move nine inches at a time. They are
composed of iron, and the shield is formed to the extent
of the proposed undertaking, being 40 feet in width and
22 feet in height. The shield is square, and after form-
ing the arch, the corners are bricked, and the square
completed ; and at no time is there more than nine
inches, and seldom above sit inches, left unprotected.
On the excavators removing the rough earth, the brick-
layers immediately follow with three courses of bricks,
which form the arch, and which is four feet in substance.
The distance trom the top of the shield to the bed of
the River is 20 feet, and the precaution exercised in the
formation of this important part of the undertaking is
a, well adapted, that in the event of any accident occur-
ring, by the rush of water or the bursting of a spring,
the top sleepers of each box, as they are called, will
Immediately unfit ; and if he danger increases, they
can brick it in, which has already been the case, when
some of the land springs, before they came under the
River, impeded the progress of the undertaking, and
which has hitherto proved effectual.
The medium of communication will be by means of
two arches, each 17 feet 6 inches in height, and 13 feet
6 inches in width, separated by a pier 3 feet 6 inches,
one of them intended for the communication from
Wapping, and the other from Rotherhithe, so that no
'possible obstruction can occur ; and the gas lights being
placed at so short a distance from each other, will pre-
sent a most singularly pleasing sight. Every 12 feet
there is an opening, by which passengers may recognize
each other, but the opportunity of passing from one
arch to another will be prevented by an iron railing.—
In each of these communications gas will be laid on,
and any inconvenience arising from this mode of lighting
will be counteracted by an admirable system of ventila-
tion, produced by an aperture between the two arches;
the draft of which, at the piesent moment, is so great,
that it will immediately extinguish a link or other strong
light, on being placed near it. The draft will, of course,
be infinitely more considerable,when these is a thorough
draft, which will be the case on Its completion. The
binding substance used in the brick work is not mortar,
but a very strong cement, in the preparing and quality
of which the greatest caution is used, and the bricks are
of a most durable description, and principally made
from the clay procured by the excavation, and manu-
factured under the superintendance of the Company.
Previously to the commepcement of the undertaking,
the bed of the River was catefully bored, to ascertain
the stratum of the soil, which was found'to be a dark
blue clay, of a vet y strong nature. The bottom, which
they are now excavating. is a gravelly soil, of a greenish
hue; and it is assumed that this was the original bed of
the River. This idea is, indeed, borne out by the quart,
City of oyster, cockle, and other shells of fish which are
almost hourly found among the clay. As the work
proceeds the boring is still continued, and they are thus
enabled to ascertain what they have to contend with.—
Thi ough the means of a very singular instrument, they
ate enabled to ascertain to a pin's point, almost, where
the termination of the work will come out on the Wap-
ping side, and in a short time to commence the opera-
tion on this side of the water, in order to expedite the
progress of the undertaking.
The length of the Tunnel, from shaft to shaft, will be
1100 feet, w hen completed ; the number of men at pre-
sent employed is about 230 (besides the Officers of the
Establishment), who relieve each other every eight
hours, so that the work is going on all night, and they
tart away about MO loads of rubbish per day. The
br'clits consumed are about 70,000 per week, and of the
casks of cement 360, the distance already completed is
about 296 feet, and the weekly progress about 12 feet.

The time and expense necessary for the pulling down
and removal of the old London-bridge will be very
considerable; a cofferdam being necessary at feet y
ore of the piers or starlings before the operation can be
effectually commenced.
Bilte/ISCUIASI MUSIC MEETING.—The Concert at the
Theatre on Friday evening, was attended by an audience alike nu-
merous and elegant. 'Beery part of the house was atm/tied to an
ovallow soon after the opening of the doors. The evening's per-
formances were excellently conducted, and many of the songs were
riteored.-Tbig bale closed the present Meeting.
r. TYIIWIIITT JONES, who is about to lead to the
temple 14 Hymen a daughter of Lord Foams*, has left the Royal
York Hotel, Brighton, for town. That Gendeman, a abort time
back, returned front Worthing to Brighton in his new vis-a•vis, at
so lipid a pace, that one of the post horses, owing to the fatigue
endured, died in the course of the night. 'lhe time occupied to
nerds this place, from Worthing, 13 wiles, it seems, did aot raccrd
an hour.