Buchanan County bulletin. [volume] (Independence, Iowa) 1869-1891, 1876-04-07
A Giant Eire.Cracker.


From the New York Evening Telegram.
Ten years ago the War Department
directed Gen. John Newton, of the
United States Engineering Corps, to
make estimates for the removal of
the distractions in the East River at
Hallett's Point, Familiarity known as
"Hell Gate" Many attempts to re-
move the distractions had been pre-
viously made, but had altogether
failed in the one great end-that of
rendering the channel safe and deep
enough to admit the passage of large
vessels. Upon the receipt of the
Generals report the sum of $4,000
was raised, partly by subscription
among our local merchants and part
ly from a grant from Congress. The
survey for the work was made in
1869.
The work itself involved the re-
moval of the Middle Rect, Gridiron,
Hen and Chickens, and Negroes Head;
virtually the complete demolition of
Hallett's Point. In September, 1869,
the first machinery was erected and
the work of burrowing into the heart
of the submerged rocks progressed
slowly but surely. The unwise delay
OF Congress in appropriating the
necessary funds, and the niggardly,
paltry allowances made, hampered
the advancement of the scheme. At
last, however, it is announced so near
completion, by the bulletin, that the
chamber prepared for the great
charge which is to rcnd the stony
mass to spllnters and make Hell Gate
terror of the past, is as large as it
is required to be. BY this explosion
the eastern entrance to the port of
New York will be open to vessels of
twenty-six feet draught. The cost of
the affair in money has been, so far,
$4,000.
The work has been under the drec-
ton OF Gen. Newton, and deserves
special record i'll the annals of Amer
lean engineering. AT the extremity
of Hallett's Point, which is laid bare
at low water, a central shaft was
sunk, and the ledge of rocks into
which it descended was surrounded
bya cotfer-dam to guard the workings
from high tides. From the main
shaft ten large headings radiate, like
the spokes of a wheel, running out
into the river-bed and under the reefs
which 1t was necessary to remove.
From these, twenty-eight smaller
drifts were driven. The larger shafts,
the chief of which was 200 feet long,
were named for various United States
officers, as the Grant, Mcclellan,
Meade, etc, galleries, and were con-
nected at regular distances by lateral
galleries, circular in form and con-
centric with the center of the shaft.
Twenty-Five and one-half acres were
undermined in this way, and one and
half miles Of tEnneling made. The
great danger attendant on the work
was, of course, that likely to result
from the caving of the roof rock. To
fully guard against this, soundings
were made all over the work at regu-
lar intervals of one foot. In ordin-
airy. cases the lead was sunk, but
where shale was met with, the patent
sounding instrument was driven
through the bed rock by boring. But
few short OF 10000 of these measure
ments were required to establish the
necessary knowledge of the ground.
The best comment on the correctness
of the measurements arrived at is in
the fact that no serious case of caving
in the galleries has occurred since
the work was commenced.
An enormous quantity of blasting
material was used; at first nitro-gly-
cerine, but later an agent composed
of thirty parts of nltro-glyoerine to
seventy OF gunpowder. This COM
pound, called vulcan powder, answer
ed the requirements better than any
other, producing the short, quick blast
required to marvel. Explosives,
equivalent on the whole to 10000
pounds of nitro-glycerine, have been
consumed in bringing the work to its
present state.
To day the mine is to receive the
final charge; III the pit or chamber,
which is thirty-tive feet deep and 200
feet in diameter, 1900 small holes,
two and n hall inches in diameter,
and from seven to twelve feet deep,
are being drilled ii the roof and sides
Of the passages for further blasts,
and are to be charged with the ex-
plosiye inclosed in iron tubes. In
the matter Qf that explosive the en-
gineers are at present in doubt. From
among the entire list of blasting ma
terial at their command they desire
to select that which can be most GER
tainly relied on for effective work.
The choice has so far narrowed down
to two, respectively known as Rend-
rock and Kleselguhr. The latter is
a German compound, an especial
favorite in tho extensive workings of
the Prussian mines. The charges
are to be simultaneously ignited by
percussion, with caps similar in prin-
ciple to those of gun.
Forty thousand pounds of nitro
glycerine are to form the grand
charge. The discharge of the vari-
Gus blasts is to be effected by cleo
tricity, and, in order to avoid the
possibility of an irregular series of
explosions, Gen. Newton proposes to
connect the mines by means of an
electric wire inclosed in iron tubing
and carried about the entire workings,
communicating directly with each
blast. A hundred and twenty men
are at present employed in drill ing the
holes for the minor blasts, and twen-
ty-one of them are driven each day.
The effect of the discharge of this
enormous magazine can easily be i'm
agined, and if, as the Superintendent
Of the works hopes, its final prepara-
ton can be reached by then, New
York will hail her Centennial Fourth
of July with a right loyal fire-cracker
indeed, The men are working hard
to get things into trim for the occa-
sion, and talk of their great work as
a worthy rival of Philadelphia's great
:. r. Il