The New York herald., 1876-09-25

north pole OF the compass moved very slowly Ave de-
gress 70 the eastward, in the general direction OF
the reef and then returned 10 It's normal position with
st slower motion. Deductions: The Immense heat
and friction produced by the explosion generated 10
caly vast amount Of electricity. which, without
doubt, Effected maRnesized objects very decidedly
I'll u was diss'pased into the surrounding matter
OTHER POINTS MANHATTAN ISLAND
observers were also stationed at the following points
ON the island but failed to perceive any Vibration -
Foot Of Grand street, East River; Union square, City
Hall Park, tho Battery, foot OF Twenty third street.,
North River, and High Bridge
Deductions: In the directions from the ceutre Of
explosion above indicated the wave Of vibration had
become entirely exhausted
BROOKLYN HEfonra
The effect on the bubble of the spirit level at this
point was quite marked. Al few moments after tho
explosion she bubble traversed three times from north
to south. but with feeble motion There per-
cepsoio movement OF the pendulum. The report Of
the explosion followed tho vibrations In about seven
seconds
Deductions: Brooklyn Heights being almost
direct line with the formation OF which Hallcs Point
reef 10 part received the shock along that line in
similar manner to Wards and Blackwell's islands
The velocity OF transmission rapid
pared with that Of tho sound, and may bc generally
estimated at double along tho axis of the reef orma.
tion.
SArSrERs HILL, Sxwrows CREEK. L. l.
This point Is to tho eastward OF the limo OF the reef
formation and southward from Haett's Point, Long
Island City. The Vibrations, which were four in num-
bcr were Indicated by the level by jerky motion
Of the bubble without any motion of direction. Tho
tumbler test showed quick agitation Of
the water, which quickly subsidized. Deduc.
tons; Tho Long Island side of the ex-
v,ln
New York. This is due the fact that deep water
ntervencs between rock formations intercept the
passage Of the vibrations. The long, marshy tract
which extends inside the Ravcnswood road Newown
Creek deadened the effect somewhat ana delayed Its
TRANSMISSION, so that in this the velocity Of tho
sound exceeded that Of the terrestrial shock.
OTHER LONG ISLAND.
AZ Locust Valley the only indication OF the explosion
was low ruEbl.ng noise like tnat OF distant thunder
but none Of the test apparatus showed any signs by
which tho least motion Of the earth could be per.
ceivcd At Jamaica tho tests made in the pres
encc OF tho HERALD observer by tho engineer officer
detailed by General Abbott for that purpose slight
vibration, lasting half minute. observed by the
instruments ten seconds after the explosion took place
The wave Of vibration was, therefore, rapidly dmin-
ishing at this point
HUDSON.
The observers at Tarrytown, lrvington and Youkers
felt very slight trcmor In the earth, but beyond this
there was nothing TO indicate the passage Of any
OF vibration. The sensation less clt elevated
points than close to tho river the low lands Tho
effects were a source Of disappointment the good
people who dwell by the Hudson, for they expected
small earthquake
GENERAL DEDUCTIONS
The predictions OF tho HERALD regarding tho move.
ment OF vibration have been completely verified by tho
observations recorded The limo of greatest shock has
been along tho axis OF the reef formation north and
SOUTH and 1t diminished tho angle OF direction with
that line increased. Tho East River has played an
important part in intcrcepting the vibration
as is shown by the difference of motion
In the ground at either side. Tho shock
diminished In torco and velocity with distance but
the latter quality great In the Immediate vicinity
of the explosion. Tho velocity Of sound proved OF
steader duration than that Of the terrestrial vIbra-
ton; that is Is decreased less rapidly In gwen time
Eastward through Long Island tho shock extended
very far, with diminishing intensity but nowhere was
the shock enough 10 fulfil the autiesntions Of
the alarmists