The Portland daily press. [volume] (Portland, Me.) 1862-1921, 1865-08-02
Wednesday Morning, August 2, 1865.
THE CHICAGO LAKE TUNNEL.


After some vexatious delays the "crib" for
the eastern end of the Chicago Lake Tunnel
was safely launched, and moored in Lake
Michigan two miles out from the shore. 1t is
a fve-sided structure forty feet in height, and
ninety-eight and half feet in diameter, made
of logs of timber, or what we used in more
primitive times to dencminate "blocks" II
consists of three walls, making virtually three
distinct cribs combined into one. The space
between each of these is eleven feet; and the
amount of lumber used is seven hundred and
fifty thousand feet, board measure. The
weight Of the iron . otis which fasten the block.
together is one hundred and fifty TONS Itis
estimated that the whole structure weighs
about eighteen hundred tons. The outside
wall has been thoroughly caulked, making ii
impervious to water, and a layer of 'slagging'
keeps the caulking in place and protects the
structure from the action of the waves
The structure contains five water tight com
partments.
Bad weather, accidents, collision with a sail
ing vessel and other causes have DELAYED the
launch of this Serbs" but this morning the
hour arrived. Governor Oglesby was present
with his staff An the inclined WAYS had been
soaped; every spectator held his breath the
axe descended, and on the instant the ponder
Gus structure glided downward into Lake
Michigan. Tie air was rent with applause
Ward, and circumnayigated the @crib !" after
which the Continental attached line and pro
ceeded to tow her out into the lake About
one hundred minutes were occupied In this op-
Grafton. Arriving at the point Of destination
II was speedily placed IN position, and the
sluices were opened 10 let it ill with water
causing it to settle slowly down about twenty
feet Five Of MitchePs marine mooring screws
were attached to keep it In place, and as soon
II ha adiucfod eor,na fat,r fI,o,,oax,I G.-,
hundred tons of stone will be loaded in, to
sink it to the bed Of the lake.
The crib win stand about seven feet above
WI ter; a1d 1t is intended to raise the top five
feet Iigner. in about two months, it Is pro-
posed to begin the excavation inside An iron
cylinder or "caisson" Dine feet in diameter will
be put down in sections about ten feet in
length, fitting carefully into each other; inside
of which, the water being pumped out, the
workmen will work at removing the earth
This will be carried away by scuws, which will
also be employed to bring back brick for the
tunnel; it being necessary to build wall as
fast as the workmen get on with their exca-
yations.
A lighthouse will be erected near the crib, to
warn off vessels; and at the same time it will
serve to show the way to Chicago harbor.
The entrance into the tunnel from the ex-
cavated end is by platform. A party return
lowered gently eighty-iye feet. The tunnel
extends from the bottom of this pit due east.
1t is eycavated into a tenacious clay, the de-
poSit of former period. This is made into
bricks, but they cannot be used for the walls OF
the tunnel. The clay contains numerous ffag-
ments of limestone, about large enough to
hurl at dog; and these, blythe burning Of the
bricks, are thoroughly calcined, so that each
brick often has in its body lump of excellent
I. -
contact with water, to become "slaked' or hy-
drafted, and by reason of the increase of size
to burst the brick to pieces. Hence it cannot
be safely used in the tunnel; but the bricks
for that purpose are brought from Milwaukee.
PROGRESS OF THE TUNNEL.
The tunnel extends from the opening about
three thousand five hundred feet. After the
brick wall has been built around it, it is left a
tubular avenue a little over five feet high
Lamps are suspended at convenient distances
the whole way; and air is supplied by small
tubes from the upper world. But the journey
TO the eaSternmOst extremity was hardly COM
Portable. Every one of the party was com
psiled to bend his body so as to enable him to
walk. This compressed the lungs; while at
the same time the air seemed to be in limited
supply and somewhat asphyxiating. Perhaps
the thought that the waters of the lake were
OuAy q tCW lcSt uDDfc, anu 1llSQG pOoSlDlJ DTc1k
through, or cause the wall to cave in, added to
the strangling sensation. The idea of being
buried in there without any funeral is not cal
cuiated to add to ones calmncss.
AT the end OF the tunnel half dozen men
are employed, by lamplight, day and night
digging away the clay, which is removed in
barrows to the mouth, and conveyed to the
surface Of the ground.
It is believed that the engineers have made
their calculations so accurately, that the party
of worbmen excaVating from the way of the
crib will, in about a year, meet those at worl
on the present tube, and the walls of the tun.
mel fit exactly together. 1t had been contem
plated at one time to set several cribs but thi.
was considered unnecessary.
The contractors doing this work are Messrs
Dull and Gowan, of Harrisburg They agreet
to perform it for $315,000; but will hardly b.
able to bring the expenditure inside of tina
figure.
IT. intended, when the tunnel shall hav
been completed, to let in the water through
the sluices in the walls of the crib. At thi
point the water is very pure and clear. Th'
tunnel ascends or slopes, as it goes out from
the shore, about two feet per mile. Many ap
prehend that the pressure of the water on it
nrst entrance viii sweep away the brick worl
and collapse the walls; but as the bricks ar
set into the clay, which is almost as firm a
solid rock, and the internal pressure of waite
Will beequivalent to that from the outside thi
is hardly to be feared
The ChlcaSo tunnel, when completed. vii
rival tne CtOdco MartnG of Rome. The con
structlon oi canal water-tight, two miles un
der the head of mighty lake is q work III
like of which is not recorded in history II
success win be the achievement of a orest ste1
forward.