Savannah morning news. [volume] (Savannah) 1868-1887, 1882-04-01
THE CHANNEL TUNNEL.
Progress of the Gigantic Undertake
ing and Location of Termfai.

From an interesting description of this
| great work which recently appeared in
the Illustrated London Neaos we condense
the following: ''The shaft upon the
| English side of the channel is sunk in
the chalk cliff between Folkstone and
| Dover, and is about one hundred and
sixty feet in depth. The opening is cir
cular, with barricaded sides, and fitted
with steam hoistiDg apparatus. At the
bottom of this shaft is square chamber,
dug in the gray chalk, the sides of
| WEIGH are heavily timbered, and in
front is the experimental boring, low
rooted, circular tunnel, about seven feet
in diameter, the floor of which is laid
with double line of tram rails. This
tunnel is admirably ventilated, and on
visiting days is lighted with electric
lamps. The beginning of the tunnel
proper is 100 feet below the surface of
the sea, and heading, now
about three.QuarteTs of mile long, has
been driven entirely through hard
| gray chalk, impenetrable to water, and
yet of such a character as to be easily
worked. The present heading, as already
stated, is seven feet in diameter. but ma
chinery has been devised to cut an angu-
lar space three feet six inches around it,
thus enlarging it to fourteen feet The
boring is done by machinery propelled
by compressed air, and progresses at the
rate of nearly an inch minute while in
operation. 1t is now going on at
the rate Of three miles a year,
which speed of working, providing
borings on the French side progress as
rapidly, will complete the tunnel under
peath and across the channel in three
years and a half. The geological ex.
perts associated with the project are san.
guine about the existence of a great bed
of gray chalk, which stretches in an
irregular curve from England to France,
starting from below Dover and reaching
to point on the French coast little to
the east of Cape Grisnez, not far from
Calais. 1t is the intention to drive the
tunnel along or through this bed. The
tunnel, when completed, will be in the
shape of a circle, fourteen feet in
diameter, but t1attened at the bottom
to receive the rails. 1t will be lined
with two feet thickness of cement con-
crete, not that it is necessary to insure
the stability of the work, but to pre-
vent accidental falls of chalk. The gra-
dients will be one to eighty on each side
until the depth of 100 feet below the
bottom of the sea is reached, after which
the line will be level, subject only to a
very slight inclination from the centre
outward. to prevent the lodging of
water. When the tunnel is opened to
traffic the trains will be run through by
engines driven by compressed air, which
not only furnishes motive power but
also ample ventilation as it is discharged.
The approaches to the completed tun-
mel upon the English side will be
strongly guarded against hostile inva-
sion by numerous Notifications, many of
which now exist, and, as an additional
precaution, means will be adopted for
speedily flooding it the entire length in
case the necessity should arise. Similar
precautions will also be adopted by
France. But these are chiefly matters
for after reconsideration. To build the
tunnel is the first thing, and, now that
matters are so well under way, there is
every reason to believe that before many
years continental tourists will be safely
and in comfort travelling more than a
score of miles under the sea, while the
winds and waves are angrily tossing the
vessels that ply above their heads.