The sun. [volume] (New York [N.Y.]) 1833-1916, 1876-03-05
INSIDE HE'LL GATES ROCK.
MAKING BEA TO Explode THREE
TONS or NITRO

Capt VIM. ii. ueuer, the engineer in
local charge OF tue work for the removal Of the
He'll Gate distractions, says that the generally
accepted Idea that the gr nd blow up wi | take
place on next Fourth OF July il not based upon
any facts OF which the engineers OF that work
have cognizance. They are pushing forward the
preparations as rapidly as possible, but are I'M
able to tx upon any date when all will be In
readiness for the grand explosion. The work OF
oxoIvating the 1875 feet Of headlines and gal
lerles was all done six months ago, but, although
there has been no delay which could be avoided,
at least three weeks must yet elapse before ali
the six thousand holes-each three inches In
diameter and averaging about ten feet In depth
for the nitro-glycerne charges will have been
drilled. Then will come the labor OF charging
those holes. and how long that will take nobody
can guess az no human prescence IN estimate
the possibilities Of accident. The rock In which
these excavations have been made IL stratihed
vertically instead Of horizontally. Hence the
volume OF leakage IA vastly increased, and
the chances Of tapping powerful vein
OF water at any stroke Of the drill
arc great. Already, in going through the
headings and galleries. one finds the roof every
where studded with projecting ends OF thick
pieces OF timber which have been driven into
the drill holes IA plugs to stop streams OF water
which without this would quickly food the en-
tire works. When the workmen come TO take
out these plugs and replace them by iron cases
tlled with explosive material, there may be very
serious inuDdation and great difficulty In CON
trolling them. Worse still, 1t is among the pos
sibltles that a premature explosion Of one Of
these charges may tear away 80 much OF the
roof ~ the works rs to drOp a Young ocean
down into the galleries and necessitate Golfer
dam around the opening from the rivers sur
face ana sui srquent pumping out volume ~
V4fY HI all tla hand autl
sniit.
TIE DANCER.
Capt. Heuer thinks there would be no danger
In iamning metal cases niied with pure Miro
piyccrne into those holes, ami sc lrce one
chance IN a million" for an explosion II the
charge Is composed ~ thirty pirts nitro gyce-
rIne L. seven parts black powder. without the
par.tilne nd woody ibre which enter into the
"lthofrtcteur.' But then he also goes On to
aver that there would no no DANGER In pounding
WITH hammer upon an iron case filled
VIII that compound. an so one Is compelled to
admire more ms courage than mis- prudence.
AT all events, rs soon "a the s5e.. wui& "
placing in each OF those six thousand drill holes
its charge Of ten pounds OF tue explosive
already described has ~ completed. aud tue
from the river will be let into the sh Il 1ll the
entire works, and the charges will be fired,
whether that time comes on the Fourth OF July
or any otherddy Delays In SUCH operations are
dangerous for verOus reason. Very lfobably,
II no unforeseen &c cident occurs the expl sion
viii ke place In June, nut uooodv need lie
awakened at nights dreading coming AS a
surprise, Tor two or three weeks notice VIII
he given by Gen Newton OF the time set for {.
No little curiosity and even apprehension
exists in the public mind respecting the effect
of the explosion OF such an enormous IN - of
nitro gycerene. Some experiments m ide with
"A view to ascertaining something OF the probi-
bilities Of suoh an event encourage the belief
that the results on the adj Icent shores AMI
even upon vessels in the water at a little DIS
lance from the explosion, will not be serious.
= he largest charge Of nitro-glycerene fred In
this vicinity and probably one OF the largest
ever exploded, was used In the demolition Of
the obstruction known as Ways reef, bout a
year and half ago. Three hundred pounds
were set OF at once on that occasion. Houses
on the line OF stratincation oi tue rock a. much
"a two and even three hundie ed wards distant
were considerably shaken, and great commo-
ton was caused in the water Bat u Is not
pounds will do much " any more.
All explosives exDend themselves In the line
OF least resistance, and this in tue instance now
under consideration, will be toward the surface
Of the river. All the galleries oeln1 tamped
with water and the rock beneath them being
solid to an indefinite de9tb, the line OF least re-
slstance will be through about six feet Of rock.
water averaging about thirteen feet I'm deptn
over the works at high tide. Iechnicallv, tue
least resistance. stones will without doubt, be
hurled out Of the water to a distance of one or
two hundred feet, but me greatest force exerted
will be upward and the area over wnicn they
Will spread viii not be great.
FORMER GREAT BLASTS.
Terrible as is the power OF nitro Glycerine
iis force il exceedingly local As an Illus
the distance Of hfty Yards the noise ana snock
produced by tho explosion OF 20 pounds of
nitro glycerine, IN g's pipe 10 feet LONG, was
not perceptiuli greater than by hring eight
ounces tthe ordinary blasting charged In tue
greater cnarge was undoubtedly lessened nv its !
distribution over so lai re an extent, anu more
severe shock would nave ensued lad II been
hred IN n compact IN IS; still the enormous DIS
proportion IN quantities producing approximate !
Gen. Newton thinks there will he no serious
effects felt ON snoie, although there may DO |
some shaking of houses In the immediate
vicinity. In the water great commotion will |
undoubtedly be caused, ana waves created |
which might inJure vessels uoored IN the vicin-
lty ny dasning them against the docks but no |
harm Will ensue to vessels anchored, or riding |
free, few hundred Yards away, and ample no
tee will he given TO enaole all to place them
selves at safe distance.
Gen. Gilmore coinrides In Gen. Newton's |
anticipations, relying upon tho well -esta blshed
f.ct OF the purely local exertion Of force b, |
nitro-glycerine, and does not think that, as |
there will Ds rom five feet to twenty-six feet |
depth OF water over tho niue wnen IL ex-
plOued, there will even be much throwing OF rock |
from the gigantic blast. All parties agree that.
plosiOn Will be bad for the 6sh 10 the neigu- |
borhood. In the torpedo experiments at
Wileit's Point great mum ners OF 1sn float on |
the surface after each explosion, some killed |
and many more Temporarily stunned. Here vast |
quantities Ill m doubt tie enec ed In like man
ncr, ~ the waters about HAlletts Point and
Flood Rock are supposed to hold great numbers |
GREAT UNDERTAKING.
1t Is scarcely possible to obtain an ADEQUATE |
idea of the magnitude OF tins work without |
personal inspection. From the 81 he idings, |
which radate from the shaft IKE the ribs Of n |
fan, and the ten concentuc galleries, the outer |
most OF which Is 100 feet long and 70 feet deeper |
than he level OF the bottom OF the shaft, mass
OF rock "a big as the new Post ONCE has been |
patiently xclvAted. The roof, ana the ll3 |
pillars left To supper. II, brlstlo with plugs |
driven In the drill holes, and the Gathering busy
air-drl Is at wor.l all the time making new bJr- |
ings about i've feet apart, To make up the grand |
total Of at least 6,O0 places for the nitro gycer-
inc charges. From chinks In tue rock |
there Is constant downpOur OF water
which cannot be excluded, and to re-
move which powerful pumps are kept |
running day ami night. Through the dimly |
lighted vistas between the pillars, sees
strange forms OF ice, like stalactites and stal
mites, Glst-ning white and gnostly. Altogether, |
the sight OF this strange construction, beneath |
the river bed, is one producing new and vivid |
impressions, and exciting admiration for the |
genius uOld enough To conceive SO simple and
effective plan for overcoming obstacles which !
have deiled the ingenuity OF able engineers.
When the charges snail have been ured, aud the
river bed dro pped down to the floor of the GAL
lefies, the entire improvement Will have cost
less than $l,0OOOOO, and from $ljO,UOO To $2uO0OJ
more Will pay tor dredging out the $4,000 cuuic |
yards of broken stone which Will nave to be re-
moved.
NEW POINT OF ATTACK.
But one serious obstruction will then remain |
to DO cleared away, tho reef OF which the pro- /
iccting point Is known us Flood Rock, six |