National opinion. [volume] (Bradford, Vt.) 1865-1874, 1872-04-12
The Brooklyn Bridge.

4 New York paper, speaking of Tho
East River Bridge, says that the pres
sure OF mir in the caisson now bulding il
thirty pounds to the square inch, OF
twice the ordinary atmospheric pressure
Once in the lock and the entrance closed
it becomes necessary TO have mn equa
amount Of pressure before the door into
the caisson can be opened. 10 this end
air is forced into the lock until the right
pressure is reached.
Between twenty and thirty mcn are q.
work in the chambers. The lowest point
reached in the excavations is within nine
feet OF the bed OF the rock. The aver
age depth of the sand, however, is about
fifteen feet. Already bouldets of trap
rock are found imbedded in the qnicls-
sand these arc broken mp aud hoisted
out by means OF an apparatus similar to
a dredging-machine, working in huge
shaft filed with water. The men work
in rslays-or watches" each "watch y
remaining in the caisson for three hours.
Working in that compressed atmosphere
has its disadvantages, and the men COM
plain OF cramps sometimes, which, iudg-
ing from their description, must be very
painful, as one of the men likened ii to
. tearin' the flesh from yer leg. The
low, dim-lighted chambers, filed with
mist, the shining pools OF water, and the
men toiling in tho flaming gas light
amid the rushing, rumbling noise Of the
sand .yphons, combine to make an in
tere,ting scene not easily forgotten,
Try and whistle, suggested the con.
ductor of the party, aud try they did,
but without success Fucker their lips,
and blow as hard es they could, no sound
approaching a whistle can be produced.
The voice, too, had a strange unnatu-
raj sound as though uttered in q high
key, oil due to the compressed atmos-
phere.
The interior Of the sidea OF the cai.sen
slopes outward, not unlike the lips of an
enormous bell. In fact, the working Of
the structure is upon nearly the same
principle as that of n diving the
pressure of the air keeping ont the wa
ter. hen the bed rock is reached, and
the caisson fairly settled upon it, the in
terror will be filed with concrete and
masonry.
Twenty courses of stone have been
laid upon the caisson, and the work i,
being pushed forward as rapidly rs pos
sible. At prssent the work 10 somewhat
retarded for lack Of stone, which can
not be supplied fast enough The
Company has expended So, 200, 00O.
This includes the amount paid for liRht
OF way. They have on band material
amounting to nearly S35o,OO0. -Four
hundred thousand dollars has been ex-
pended for lumber, and $4,000 for ma
chinsry. IT is worthy Of remark that the
Company having the stone contract Of
fered $20,000 10 be released from their
contract. This offer tho Company de-
clined, believing that they could not
make such advantageous terms else
where.
Doubts have been expressed as to the
stability OF so huge structure. In re-
gard to this point, the su Nerintendent
states that the opinions of the most dis
tinguished engineers have been sought
upon the subject, and they fully indorse
the plans. Il hss been thought by some
that it would be necessary to build
pier in the middle of the river. This
would be impossible, from the fact that
Congress would. never permit it, and
even if it were built vessels would be
constantly carried against it BY the force
OF the current and injured, and the
Company continually involved in suits
for damages. A wind travelling at the
rate of sixty miles an hour, which is an
extreme case, would no. sway the bridge,
even at its great elevation. II is OK
nected +hot steam cara will RIM across
the bridge at the rate of twenty miles
an hour. The entire cost of the struc-
ture, when completed, is estimated at
$l2 100000. This is thought 10 be an
outside figure.