The Portland daily press., 1870-05-12

cfTwcnfy-fhfee foEs of Powder
The San Francisco Bulletin gives descrip-
ton of the removal by blasting Of this serious
obstruction to navigation in San Francisco
harbor; an immense rock Of soft sandstone,
$50 feet long, 90 feet wide, on tie abrupt sides
and comparatively smooth surface.
The first work attempted by the engineer
was to reach the rock. For the accomplish
ment OF this task a large, staunch, hat-boi-
toned scow was constructed, ard heavy
framework, thirty-four feet long, twenty-five
feet wide and twenty feet high, erected upon
1t. A double tank or Golfer dam, about eight
feet square, was built of plank IN the center
OF the craft, running from its bottom 10 the
top OF the platform, similar to a fishing-smacis
well-room. The space Of two feet was left be-
tween the outer and inner castings Of this
tank, was filled with tough Cay, packed in
bags, thus effectually shutting of the water
from the outside. The bottom OF the scow
was armed with number Of sharp, steel
pointed spikes, arranged in a semi. circle near
the outer edges, and, after thorough inspec'
ton and overhauling, the whole structure was
towed to the spot by steam tug The craft
was sunk upon the comparatively smooth sur
| face of the rock, anchors were carried out in
| different directions, with the chains hove taut
| on board the vessel, and two hundred tons of
| rock thrown in. The spikes penetrated the
| sandstone on account of the pressure brought
to bear upon them, and the structure, which
| rises eight feet above the surface of the water,
| was immovably set. The water was easily
pumped out OF the dam, and the surface of
the rock laid bare for further operations by
the workmen A circular groove, two feet
deep, was drilled in the rock, into which an
iron turret was hoisted and firmly fixed.
ExcAvATING THE ROCK.
The surface of the rock having been expos-
ed, a shaft was sunk to the dep,h of twelve
Feet from which tunnels were run in different
directions, the ballast worked being brought to
the center shaft, hoisted in a tub through the
turret, and discharged by swinging derrick.
When the work of excavatiug was COM
pleted the rock resembled a huge bake-kettle,
with its top supported by pllars,4ett to sus-
tain the roof against the outside pressure.
The internal Dimensions of this great cham
Der was 1872 feet by GO feet wide, with height
diminishing from II feet at the shaft to feet
at the lowest point. The crust, or top was
between ten and eleven feet thick.
CHARGING THE BLAsT-TuE SPECTATORS.
Thousands of men, women and children
came from all parts of the city TO see this IA
nous rock blown to fragments with twenty
three tons ofpowder sunk in its deep caverns.
Many expected to see a column Of stones, and
timbers thrown 200 or 800 feet into the air,
and calculated the chances OF the entire city
being shaken to its foundations. They wish
ed these results might follow upon the ex-
plosion. Certainly twenly-three tons o. sun
powder is an immense charge, and 10 expiode
it under ordinary circumstances would 0e
like blowing up a good sized powder-mil.
This huge quantity was contained in large
boiler-iIon cylinders. Early in the week IT
was taken to the ra"l Nv, ON 2 h1Ige ara placed
| I. .l,t ,,Air q q N
which the electric wire was run, so as to ex-
| plode all of them simultaneously. When the
powder was all in, the anchors, chains, tools,
| engines &C., were all taken away, leaving
| nothing of value to be involved in the general
| wreck. To those who wished to witness the
spectacle from the land, Telegraph Hill afford
ed the best and most popular view. BY II
M. Saturday people commenced threading
their way on all sides toward the summit OF
the hill. The cars on the line of street rail-
roads leading to North Beach were crowded
with men, women and children, and bv l
o'clock p. NJ. Telegraph Hill was black with
the multitude North Point and Meige's
Wharf were also thronged, and docks and
shipping, wherever a view OF the locality
could be obtained. One speculative individ::
| ual stationed large telescope on the summit
| of the hill, but very few availed themselves OF
| the opportunity, and he turned the instru-
1 menu SkyWdlu. huNCibioiIlSs dSChlo WV
| also on hand, who at intervals flung thous-
| ands of their hand-bils into the air. Candy
| and fruit hucksters struggled about aud di-
verted much coin to their pockets. Those
/ persons who had opera-glasses were much
| envied. Several enterprising, disoensars o.
| nulds packed beer-barrels up the hill, and did
| a good business, while their stock in trade
lasted. Yachts, steamers, tugs, schooners,
sloops and row boats dotted the bay in all d-
| rections, but all kept at respectful distance
| from the rock, above which the American flag
| was flying, and near which the boats Of the
| engineers lowered. At p. NJ. gun thun-
! dered from Alcatraz, and startled hundreds
| who thought the monster blast bad been ex-
| ploded. By this time at least $4,000 people
were present; the appearance OF Telegraph
| Hill was inexpressbly grand. The whole Ie-
| sembled grand army. On all the streets
l and roadways at the base were hundreds OF
| carriages, buggies, wagons and vehicles of all
| kinds all loaded with people. At LIS the
| last signal gun was fired from Alcatraz and
| everybody expected to see the rock shattered
| The sc0w with the engineers was anchored
I at safe distance, but when the time come
| for the explosion to take place, staff on the
framework OH the rock fell, and after about
fifteen minutes delay, boat with several
men put off from the scow and landed them
| on the rock again. 1t was evident from the
delay and the movements OF the men that
some accident had happened, but what 1t
was no one on shore could determine. The
people grew impatient, but i'll shoit time
the small boat put off toward the scow, ano
expectation was again on tip-top.
THE EXPLOSION.
| At 2:06 p. NJ. the eXplos ion took place. A
monster cone of the water, apparently 100
feet in diameter at the base, shot into the air
to the height of at lsast 100 feet, and in the
| center, like the crater of q volcano, could be
| seen sheet of smoke and stones, the latter
| going far above the vast column of water.
There was dead, thug-like sound; the great
cone was shattered into spray and fell, the
rocks descended piunging into the bay, and
| all was over save the great white circle of
| foam which marked the spot. Not single
| vestice of the framework was to be seen. I'm
mediately guns were fired, whistles sounded
| and bells were rung.
A great shout went up from the assembled
| multitude and then came the dispersion, as
OF some vast army, panic-strickeA and 10
| flight. Probably more than $4,000 people
| witnessed the grand spectacle, such sight as
never was presented in this city before. Along
every street ratified thousands of WAGONS and
carriages, and horsemen dashed rapidly here
and there. The sidewalks were lined, and the
crowd seemed more immense than when
gathered on the hills. The feet OF sailing
vessels and steamers headed toward the spot
where Blossom Rock had been, and hundreds
of people who had the leisure remained to wit
ness further proceedings, whatever they might
be. No rock went out of a perpendicular di-
| rection but huge bouders weighing tons were
| thrown high in the air, amid storm OF small
er ones. The sight was magnificent ore
but there was much less commotion on the
water than many had expected. The shock
was felt by people in boats but there was nc
| perceptlble jar on shore az the nearest point.
/ letter from Vass..lr,aro