The Findlay Jeffersonian. [volume] (Findlay, Hancock County, Ohio) 1870-1881, 1876-09-29
NO.. q
sreHsneaus.
THE HELL GATE EXPLOSION.

q
lantic Ocean, lessening the time bs
tween this city and Europe by twenty
four hours. The last OF September ha
been fixed upon by Gen. Newton, the
United States engineer in charge of tbs
work, as the time when the final ex
plosion is to take place.
Many suppose that this rock is il
the middle of the stream, but it is 6
part of and projection from, the
shore of Long Island, running fal
out under the water Being on a point
around which the stream makes a bend
OF nearly 80 degrees, it causes The cur
rent TO set so strongly toward the op
posite shore of Wards Island that ,
wreck is invitable to any vessel which
attempts to make the passage wheI
there is not wind enough TO carry
her through. Persons living near the
point say that two or three vessels d
week are often thrown upon ''rha
Gridiron" the opposite rock, and thai
many Of these are so shattered that
they are dismantled and sold for old
lumber. The removal of the great
rocky bar upon the point will give the
current another and more direct course
and greatly deepen the channel.
The approach of the excavations
is along the shore, after leaving the AS
toria Ferry, and the visitor comes sud.
denly upon a deep pit, called a ''shaft"
and guarded by few posts with boards
nailed across them. Around the mouth
of the pit great heaps of stone give evi
dence of the amount that has been tax
en- out, though much of it has been re-
moved from the place. The whole
quantity excayated from the shaft and
the tunnels has been over 80, 900 cubic
yards This stone is shornbleude gneiss, a
metamorphic stone ofalmost the same
composition rs granite, from which it
differs by layers of quartz, mica and
feldspar. 1t generally has tendency
to cieave along the planes where the
mica exists in the greatest q q,.anities.
The stone is very hard; harder than
granite. For this reason and on ac
count of the seams in the rock
in some places which admit the water
from above into the tunnels, the work
which has been very difficult. The shaft
is 80 feet deep and 100 feet in diameter.
On the water side a cofTerdam, in
the shape of an irregular pentagon,
keeps out the water. On the land side
of the shaft are the various buildings
necessary for the carrying on OF the
the work. There is an engine house in
which are the great air chambers by
means of which the air was compressed
until it gave the requisite number of
pounds pressure 20 the square inch, and
was conducted thence in the tubes to
the Burleigh drills fur below in the
tunnels. Near the building are the
shops, engineers offices, etc.
Ten vast portals, looking like the en-
trance of gret tombs excavated in
open side by side around
two thirds Of the circumference of the
shaft. They are the entrance to ten
large tunnels and to the network OF
small tunnels which undermine the
rock. Within water pours down in
streams OF certain points and drips con-
;tantly at others, making necessary the |
continued use of pumping engine,
which stands in the middle of the shaft. I
The tunnels have been entirely cleared /.
IF pieces of stone and rubbish, and the .
1lan Of excayating leaves the roof sup
ported by 172 piers, each s feet square
Lud varying in height from 90 feet near
he shaft to 10 or 12 feet near the outer /
circumference of the excavations. The 1
ntire work Of boring has been com /
'leted, and nothing remains to be done
xcept the manufacture of the explo.
i've MATERIAL and placing the charges in
ne holes prepared for them. In the part
f the rock which forms the roof $500
oles have been bored in an Upward
ERECTION, varying in depth from to IL
set, and all three inches in diameter.
he columns lave been pierced, also,
1 the same manner from floor to roof.
hese holes will receive the explosive
harges, which will be dynamite where
ne rock is hardest, and ordinary vulcan
owder where the superintendent A.,
lass is more pliable and less dense in T..
5 consistency. The entire roof ana
1lumns will be demolished at the 4,
Tine instant.
Nitro glycerine was for time +,
lought Of as the most suitable explos
!
was rejected-not as too dangerous. !
ut a ineonvenient 20 use on account 3,
leakage Dynamite, which is COM +,
1sed of % per cent of clay and - (
n cent Of nitro glycerire, Was finally ]
lected FOR blasting ,he more solid por-
1ns OF the rock. TIE charges will be
1t into ,,.s about 2 2 inches in di-
meter, and varying in length accord
9 to the depth of the holes. These a
IS will be placed in the holes, and $
eli CONNECTED by short wires with the Z.
lg wires which extend to Tie batt,r :,
!. \ bomb proof chamber viii BE- 5
epared for the operators Of the bat /
> at some distance southeast Of the ::
lin shaft, and in the direction Of the II
-vrns good road. In this chamber h
Il be placed at least 200 Gove's gal r.
mic batteries, and each Of them will :,
olCde from II TO 20 charges. Amin =,
Nous scheme has been devised by q
Iich all these batteries will BE- b
ought into action at the same in
mt, and thus complete circuit will re
formed, firing all the charges to d.
-her, aud utterly destroying the al
lteau Of rock which has hitherto
s'ructed navigation except for small II
fits through He'll Gate channel. I'll
ien. Newton has taken up a con -
ut series of experiments 20 insure a tb
-iect success when the great day ra
lIes, and there IS 10 reasonable th
Jund for fear Of any accident. The p
-iuaaT- are cf fl.a s-,ii.;oD that tLa