Memphis daily appeal. [volume] (Memphis, Tenn.) 1847-1886, 1870-05-05
EXPLOSION OF % TONS OF POW
DER.
Blasting of Blossom Rock in San Francisco
HarbOr--DescriptiOn Of the Rock and
the W0rk---Picturesque and
Thrilling Scene.
From the San Francisco Bulletin, April

From the San Francisco Bulletin, April
l5th.l
a very efiectual means for remov-
ing rocks in harbOrs consists in ex-
cavating a great part of the interior,
which can be easily done provided
the rock is of soft texture, favorable
shape and not too much broken.
When the requisite space is formed,
quantities of powder in great tanks
Or bombs are placed in the chambers,
the water is permitted to flow in and
fill them, and the blast being exploded
the shell of rock remaining is blown
to atoms. 1t has never been found
that fragments of rock were thrown to
any very considerable distance by
submarine blasts; the resistance of
the water preventing it. The first
operation in this harbOr on the plan
last mentioned, was performed by
Mr.. Won Schmidt in removing the
ledge at the mouth of Hunters Point
Dry Dock, and ii was quite successful
there. The same plan has been fol-
lowed in the case Of Blossom Rock.
by the same engineer, and will doubt
less be adopted elsewhere in harbors
and rivers.
BLOSSOM ROCK
lies directly ia the line of entrance to
the harboT, and near the route whichli
the river steamers take, and is a sunk
en- rock. The engineers of the United
coast survey marked its position
with buOys, which have several times
been swept away. The water at the
rock at low tide was about five feet
deep, and the current at the point was
generally very strong. Several YES
sells have struck on it, and it has al
ways been an object Of dread TO sea
and navigatOrs. Last wear the
Government appr0priated
SO, 600 ia currency for the removal al
the rock, and the plans presented nv
Colonel Won Schmidt We're adopted
The rock had been carefully snr-
and found to be 1870 feet long
" feet wide, with abrupt sides, and a
comparatively smooth surface. 1t was
soft sandstone like that in Telegraph
Hill and Alcatraz Island. The first
work attempted by the engineer was
o
REACH THE ROCK.
For the accomplishment Of this task
large, staunch, fiat-bottomed seow
vas constructed, and a heavy frame
work, 81 feet long, y feet wide and 20
eet high, erected upon it. A double
ank or Golfer dam, about eight feet
quare, was built of plank in the CEN
er of the craft, running from its bot
ON to the top of the platform, similar
0 a fishing smack's well-rOoln. The
pace Of two feet was left between the
utter and inner castings Of this tank,
7as filled with tough clay, packed in
ags, thus efIectually shutting Off the
yater from the outside. The bottom
{ the scow was armed with q number
{ sharp, steel-pOinted spikes, ar
lnged in a semi-circle near the outer
1ges, aud, after thorough inspection
nd overhauling, the whole structure
as towed to the spot by a steam tug.
he craft was sunk upon the com ,
aratiVeiy smooth Surface of the rock.
nchors were carried out in different :
irections, with the chains hove taut !
q board the vessel, and 80 tons of
thrown in. The spikes peuetra- J
d the sandstone on account of the :
ressure brought 70 bear upon them, !
i'd the structure, which rises eight !
above the surface of the water.
as immovablyset. The water was
silly pumped out Of the dam, and !
Ie surface of the rock laid bare for q
rther opeIetiOns by the workmen. g
circular groove, tive feet deep, yaSl~
nIled IN the rock, i9 FFkieST RneFTvF,
irret was hoistedEN., MAY 4. is7S.-Strat
EXcAVATIY, 3 bales cottOH; Jones
The surface Of tPi stewart Bros q Sizer