Evening star. [volume] (Washington, D.C.) 1854-1972, 1900-05-19
DESTRUCTION Of sHAG ROCK.
Large Obstruction In San Francisco
bay Blown Up.
tha

From the San Francisco Chronicle.
Shag Rock. a meniee for years to bay
navigation, was blown out of harbor and
off the chart a 3:03 O'Clock yesterday after
noon. Nine tons of nitro-gelatine loaded
into thirty-four holes, each nine inches in
diameter and extending straight down into
the little islet some thirty-1hree feet below
the surface. was the tremendous power
that rent the mass asundet and directed a
mighty column of water a thousand feet in
the air. -, -
The sight was one to impress even the
most stolid of witnesses. Warned of the
hidden force about to be let loose, all man
rer of craft kept a mile and hall away.
Even the barge from which the current
was to flash the spark into the hidden rock
drew back until she paid out more than "a
mile of the small electric cable. Then the
tugs slipped away from her and swung
round into position with bows pointed in
the direction whence they had been led to
expect the onrushing wave following a
gigantic upheaval of waters.
Without warning. almost without sound.
there arose from the unrufiled surface of
the bay a towering. feather-edged, whitish
mass. Majestically 1t mounted still higher
and higher while two great lateral fila
ments like dropping ostrich plumes broke
away and fell gracefully out from the ris-
ing column that then for an instant resem-
bled fieecy fieur-de-lis. Still the huge jet
kept rising. Then there surged up from be-
meath through the whole lower part for
several hundreds of feet yellowish cloudy
tint that blended into the s!lvery wilderness
above. For 4 very small part of second
the tower stood as if cryStalized, and then
it dropped swiftly as 1t had assembled and
as noiselessly. Fifty feet from the sea it
finally spread out umbrellawise in dirty
coffee-colored fountain that spashed up
the surrounding muddiness and created for
SECOND n
spot where Shag Rock had been. The
whole spectacle lasted not more than a
dozen seconds.
AS there had been only a strange omin-
Gus '.whoof' when the water leaped aloft.
so there was scarcely a commotion as it
| returned to the bay almost in time to refill
the vortex that it had created. There was
no outruShing, billowy wave, no threaten
ing concentric series of waves. AS soon
as the thing was done the boats that
watched the explosion from sa fe distances
bore down on the scene-a small fleet of
rowbOats. fishing boats with sails hastily
set, four steam tugs, a smart sailing yacht
dingy schooner and three gasoline
launches. all conVerging upon the half acre
| of wreckage and yellowish scum, wher: it
was expected there would he myriadS of
dead fish upon the surface. Except for a
porpoise or two and few rockcod. no dead
fish We're to be seen, but here and there
great bolted timbers the size of telegraph
poles, hoated in pieces, torn and twisted
and violently rent asunder as by lightning.
Contractor AXmann believes that the ex-
| plosion was a success and congratulates
himself upon the favorable conditions of
the weather and tide. AT the outset there
was some delay at the rock while William
Brawley, an electrical expert. tested the
wires connecting the caps. This was a
hazardous undertaking. and made the cold
chillS run up and down the backs of the
half dozen men comprising the crew of the
barge. 1t was a light current, however,
just sufficient TO show that all was intact
Shag Rock IS estimated to have contained
about $500 cubic feet of sandstone slight
ly metamorphic. AT high tide only about
ten feet of Its crest showed. Contractor
AXmann was awarded the contract last De-
cember for its destruction. The first two
months were spent in getting drills and
machinery in place: then the actual work
of drilling began. In all thrty-four holes
We're cut varying In depth from a few feet
to fifty feet Into these holes the gelatine
WAS firmly rammed with heavy steel bars
At the mouth Of each hole four specially
prepared caps We're placed. These caps
contained about half Il pound of illuminate
OF mercury, in which was imbedded a
small platinum rod connecting the positive
and negative wires. The electrical current
heated the platinum TO a red heat. which
in turn ignited the illuminate of mercury
As the selatine used is difficult to ignite
contractor AXmann took the preCaution of
surrounding each cap with dynamite, thus
lnsuring the success Of his venture.
According TO the terms of the contract
the rock must be leveled to depth of thir-
ty-four feet at low water. 1t IS quite posi-
BILE that the depth viii be found greater
than necessary. The effect of the gelatine
was visible toward the center and In the
direction OF the greatest resistance. If the
force expended is as great as the experts
estimate 1t will be found that there Is moth
ing of Shag Rock left.
From AlcatraZ Island the height of the
column was ascertained by angular meas
urement. According to the figures of Engi-
neer Demerritt, the column reached over
1000 feet.