The New York herald., 1876-09-20

explosion will DO very Considerable. But another point
must be remembered in this connection, and that 10
tho rspidity Of combustion which 10 pcsuliarty Of
tho explosives used. Water rcsists sudden appics-
tion of pressure but yields easily to slow This
Is very simply illustrated by dropping stone into
pond from great hoght and repeating the operation
close TO the surface II u stone IL thrown or the top
OF High Bridge into the Harlem River ,t strikes
the with great force causing break in the
face OF tho river which could only occur through tho
offering powerful resistance the passage OF
the The stone then sinks TO the bottom With
comparatively slow descent Now, take another
and hold only foot above the surface OF the
Drop and will enter the without any
disturbance and will reach the
height II shows therefore, that when q powerful
blow suddenly administered 10 q water surface the
resistance viii be in proportion 10 the energy Of the
shock, and in this way Is possible show that
forms greater obstacle TO tue expansion OF tho
from the exploding cartridges than the rock sof that
surrounds them the ressta OF the latter being
variable, whilo that OF The former Is Augmented,
explained above
With tho cavornous chambers then filed with water it
will DO impossible for the charges fail destroying
the rock columns completely, provided the former
are properly located aud of the necessary strength
Regarding the flooding OF the workings o measure
OF against the projection OF pieces OF rock
II can be readiiy seen that II will prove enectual
OF rock thrown upward from
great depths OF water by the force Of explosions
that there ,s necessarily danger 10 be apprehended
HaetIs Point, but The circumstances that surround
this unique work disr wholly from those attendant
on ordinary submarine blasting II has been shown
that tho roof rock acts as guard against the Lying
upward OF pieces from tho columns; It has also been
shown that water rcssts pressure proportion to tho
force Of that pressure. IL may be also stated that
body moving through water, either slowly rapidly,
tends TO follow tho line OF least resistance,
which would be limo perpendicular to tho
surface. Therefore a mass OF rock flying
tho centre OF explosion should first
overcome the resistance OF the water which would
tend 10 decrease its motion; second, IL would be
stopped by the descending weight OF the roof rock;
and, third, II neher OF these influences acted
decidedly It's movement its course should Of neces
sity be upward in perpendicular line, and ts fall
naturally in tho exactly opposite direction No
ever saw piece OF stone blown out OF deep water in
direction at less than night angle with its surface,
therefore all fear OF lying Jumps OF rock reaching New
York, Astoria or Wards Island might DO dismissed as
absurd.
When all the other preparations completed tho
operation OF filling tho Workings will be accomplished
by Of siphon which Is arranged TO pass
through the Golfer dam and admit the water with an
easily regulated flow. We present diagram OF the
syphon and It's modo of operation with the present
article When ready TO be used and tho tide at the full
hcght tho inlet valve will be opened tho top OF the
syphon, on which the water viii At once flow
tube. Az the tide falls below the level Of
the top Of the tube tho flow Will cease
ter peculiar 10 siphenic action The water will be
drawn into the tube by the difference OF pressure Of
that tho wator on tho long end This can be ex-
pressed by the difference between tho weights OF the
long aud the short columns OF wator, the operation OF
tho syphon being dependent disturbance Of tho
equilibrium OF pressure. When the excavation 10 filed
10 the river level the eotcr dam will be partially re:
moved, TO admit OF tree flow Of water IA and
out, according as the tide rises and falls
THE BOMB PROOF sHELTER SoR THE BATTERIES.
AS an extraordinary precauton against accidents
General Newton has caused to be built stout bomb
proof building shctering the batteries during tho
explosion Tho structure. OF which sketch Is givcn
herewith, Is a solid framework OF heavy tmbers
braced and supported IN the most substantial
manner and sheoted ovor with pine boards firmly
spiked TO the framing. Over all this 10 built
of dry masonry many feos thick and strong enough
resist the assaults OF artillery Within the building
that required for the explosion. Although this
precaution was adopted Il is certain that no injury
would have reached the batteries their connections
GENERAL xyFRcr or TIKI EXPLOSION.
Although much alarm exists respecting the OBJECT Of
the explosion Of SO much nroglycerine and dynamite
within contracted space, 's wholly groundloss when
tested by tho conditions which are believed 10 be ts
exciting cause. The rock columns which will really
transmit downward ahock to their bases, because
they wholly isolxted from each other by the sur
rounding water, and the roof rock through
which shock might be transmitted to tho permanent
portion OF tho root will be scporated from II At tho
same moment that the columns are rent. heavy
blow that will DO fclt distance from than
close up the explosion will certainly result but
1t will not DO OF chsyscter TO cause serious alarm.
Tho theory OF General Newton regarding the effect Of
the ''blow up IL perfectly correct, Notwithstanding
tho efforts Of the aarmists that seek to subvert it.
works and tho police will prevent any accident
curing to adventurous persons who may desire
p nun w AWAIT hs sa
groat ovent with the utmost confidence
THE ExCITEMENT OVER THE COMING xxPLo-
sIoN-sCARE AMONG THE PEOPLE OF AsTo-
nIA-A MAY MORNING IN sEPTENBER-LooK
OUT FOR THrEvEs-rHE WORK APPROACHING
COMPLETION
mo dynamite 4" still the cry at the government
works at He'll Cato yesterday and consequently tho
workmon 'busy doing nothing" tho foreman
expressed it. In other words they were moving scat
folding In the tunnels, carrying OF implements no
longer required in the mine and doing whatever could
bo founo TO kcep OF mischief and In working
order ready handle tho anxiously looked for material
when 1t should arrive. Carpenters employed all
day building and getting into place series Of
made Of inch pine plank, each about twolve feet
long and foot square tho clear. These will be
joined together endwse TO form a continuous trough
or case which will from tho bottom OF the shaft up
to surface Of tho ground and thence the
Dombproof structure containing tho battery. Ra-
dating from the end of this box, which upon
the floor of the shaft will be smaller boxes OF
similar character, ono leading to the mouth of each
heading Through each OF those smaller the
poding wires from its own heading will be thrust in
order keep them from injury from falling bodies
ohcr causes All tho wires from tho entire 1S0 groups
will thus converge the argor box ppo and pass
through it to tho battery. Tho sphon, already do
scribed, also completed yesterday.
DYNAMITE COMING.
Lato In the afternoon q message received from
the contractors stating that tho dynamite was then
being shipped and would be delivered early hour
this morning Should It arrive without ACCIDENT tho
work OF charging the holes, which is yet
pleted, will at oncc be proceeded with and at the
time the nllng OF the primers explodent cartridges
will 90 on in tho little temporary sheds erected for
that purpose four different points upon the grounds
should nothing unexpected happen, tho charg-
ing putting in the primors and flooding tho
excavation will probably all be completed by
Saturday night In that case the explosion
will occur on Sunday next, General Newton will not
permit the mino to remain moment longer than is
necessary after the arrangements shall have
pleed Tho General has boon much annoyed by lot
from persons seeking to verify tho correctness Of
statements made by newspapers to the effect that tho
"big blast would occur on certain days He has
been able TO do than con ecture the time