The daily Argus., 1876-03-04
A rREMENDous EXPLOSION

A TREMENDOUS EXPLOSION.
Preparations for Blowing Up the Final
Charge at He'll Gate IN New York
Harbor---Forty Thousand Pounds of
Nitro-glycerine to be Exploded.
From the NeW York Sundny Telegram
Ten years ago the War Department
directed General John Newton, of the
United States Engineer Corps, to make
estimates for the removal of the OBJ
structions in the East River, at Hallett's
Point, famihary known as
HELL GATE"
The survey for the work was made in
1862 The work itself involved the re-
movol of the Middle Reef, Gridiron, Hen
and Chickens, and Negro's Head, virtu-
ally the complete, demolition of Hallets
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 aDpropriating
the necessary funds, and the niggardly and
paltry allowances made hampered the ad-
vancement of the scheme. At last, how
ever,it is announced as near completion, by
the bulletin, that the chamber prepared
for the great charge which is to rend the
stony mass to splinters, and make He'll
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 opened to vessels Of twenty-six feet
draught The cost of the affair in money
has been, so far, $750,000.
The work has been under direction OF
General Newton, and deserves special
record in the annals Of American engineer
ing. At the extremity of Hallett's Point
which is laid bare at low water, a centra
shaft was sunk, and the ledge of rocks into
which it descended was surrounded by 9
Golfer dam to guard the workings from the
high tides. From the main shaft ten large
headings radiated, like the spokes of a
wheel, running out into the river bed and
under the reefs which it was necessary tc
remove. From these, wenty-eightsmallel
drifts were driven. The larger shafts, the
chief of which was 200 feet long, were
named after various United States officers
as the Grant, Mcclellan. Meade, etc.
gallaries, and were connected at regular
distances by lateral galleries, circular il
form and concentric with the center of tht
shaft, Twenty-Five and half acres were
undetermined in this way, and
MILE AND HALF OF TUNNELLING
made. The great danger attendant on th'
work was, of course, that likely to resul
from the caving of the roof rock. To full,
all over the work at regular intervals O
In ha
sunk, but where shale was met with tn,
patent sounding instrument was driver
through the bed rock by boring But few
ments were required to establish the neces
sary knowledge of the ground. The bes
comment on the correctness OF the meas
urements arrived at is in the fact that n,
serious case of caving in of the galleries ha
occurred since the work was commenced
An enormous quantity of blasting materia
was used; at first nitro-glycerine. but late
an agent composed of thirty parts o
nitro-glycerine TO seventy of gunpowder
This compound, called vulcan powder
answered the requir ement better than an.
other, producing the short quick blasts re
quired, to a marvel. Explosives. equiva
lent on the whole to 100000 pounds @
nitro-glycerine, have been consumed i
bringing the work to its present state
To-day the the mine is ready to re
ceive the final charge in the pit O
chamber, which is thirty FIVE feet dee
and 200 in diameter, 10000 small holes
two aud half inches in diameter, an
froE seven to twelve feet deep, are bein
drilled in the roof and sides of the passage
for further blasts, and are to be charge
with the explosives inclosed in iron tubes
In the matter of that explosive the Ell
gineera are at present in doubt. From th
entire list of blasting material at the
command they desire to select that whic
can most certainly be relied on for effe
tive work. The choice has so far marrow
ed down to two, respectively known
Kendrock and Kieselgurh. The latter is
German compound, au especial favOrite
the extensive workings of the Prussia
mines. The charges are to be stimultan
ously ignited by percussion, with cal
similar in principle to those of gun.
A GIANT CHARGE.
Forty thousand pounds of nitro -elycerir
are to form the grand charge. The di
charge of the various blasts is to be effec
ed by electricity, and, in order to avoid th
possibility of on irregular series of expl
sions, General Newton proposes to come,
the mines by means of an electric wire il
closed in iron tubing and carried about ii
entire workings, communicating direct
with each blast A hundred and tweni
men are at present employed drilling ii
holes for the minor blasts, and rwenty-o
OF them are driven each day. The effe
of the discharge of this enormous mag;
zine can easily be imagined, and if, as Il
superintendent of the orkihopes, its fin
preparations can be reached by then, Ne
York will hail her centennial Fourth
July with right royal fire-cracker indee,
The utility of the proposed explosion e,
tends beyond the addition it will make
our noisy national holiday, and when ii
stately ships sail down the sound, an
New Workers, passing through the Ea
river, look in vain, for the seething eddie
of old He'll Gate, the toll Of the long yea
will have its own reward in the. new gat,
way to our matchlcss harbor, which it b,
thrown open to the world.