The Portland daily press., 1863-04-10

Dut as tue new Ir0nsides VIII not be able to
use but one broadside at a time in an attack
upon Sumter, one-half of her broadside guns
should be deducted-1440 Ibs.-which would
give total weight OF 1892 lbs. of metal which
can be hurled at given moment upon the
rebel works!
Guns OF so large caliber cannot be fired rap
idly, not oftener than six or eight times an
hour. Time must be given them TO cool. Six
ty times a day is probably the maximum. At
that rate the expenditure of ammunition will
be enormous. A single 1l-inch gun fired six
~ times, or once every ten minutes for ten
hours, will throw ten thousand eight hundred
pounds Of metal. A l5-inch gun fired with the
same rapidity will require t,oeaty-eiqht thou
sand fire hundred and sirty poundsl Any
one OF the Monitor class will require thirty
nine thousand three hundred and sirty lbs.,
nearly ttcenty tons Of shot Each Monitor
Will also use about two tons of powder per
day. The entire fleet, working at the same
rate, Will hurl at the rebel fortifications four
hundred and fifty thousand pounds of iron
an ten hours, at an expense Of fifty thousand
pounds Of po,cderi or two hundred and
tacenty-fce tons Of shot, and t,centy.fre tons
Of potcder!
This is maximum. The fire of the feet
cannot be thus sustained. 1t probably will
fall far short of it. But these are elements
which have been taken into the calculation.
But will this tremendous weight Of metal
be hurled with sufficient power to destroy the
Notifications of the enemy? 1t is an estab-
lished rule that the penetration of projectiles
is proportonate directly to their weight and
to the square Of their velocity. The theory
of our artillerists Is that very heavy shot
thrown as it necessarily must be at compar-
lively low velocity of about 500 feet per sec
ond of initial velocity, is more destructive in
the end than lighter proiectiles thrown at
high velocities. English artillerists take diff
ferent view, and believe that a lighter shot
thrown with almost lightning velocity will be
more effective. This point is not yet settled
The approaching engagement will perhaps
in measure determine it. Admiral Dupont
has large guns, and his fire must be slow. de-
liberate and sustained. The rebels have some
English Whitworth guns, probably Z or inch
caliber, throwing rs and $50 pound shot
They will use high charges of powder, twen-
ty-fiye pounds, and obtain an initial velocity of
1900 feet per second, but even those charges
will not probably pierce the turrets of the
Monitors.
When we speak of ball moving at an ini-
tial velocity Of 1000 feet per second, it is not
meant that the ball actually passes through
1000 feet in the second, but at given instant
moves with a rate which if continued would
produce that result. The moment ball
leaves the muzzle Of a cannon ii begins to meet
atmospheric resistance, and its momentum is
retarded. The initial reiocity of the ball is
the rate per second at which it moves at the
beginning of its flight Atmospheric resist
ance is less in the conical, elongated proiec-
tile than in the sphere. The Armstrong gun
and the Whitworth gun throw elongated pro-
jectiles. 1t is not known that the rebels have
any OF the Armstrong guns in position; prob
ably they have none, inasmuch as they are
very costly. and also inasmuch as the English
government take all that are manufactured.
Tha ,r... al. n. ka,-a ln,..
the original Monitor in the engagement with
the Merrimac, the Montauk, Passaic and Ma
hant at Fort McAllister. Torpedoes are
more TO be feared than the guns from the rebel
forts and batteries. There will be points
where shot from Sumter, Moutre, Fort John
son. Morris Island and Sullivan Island will
fall like hail around and upon the attacking
fleet, but the swiftest flying bolts, the heaviest
shot, judging from what has been, will roll
off harmlessly, leaving no deeper dents than
the hailstones of a June shower upon shin
gled house roof.
But there is still an important point for
consideration. Will the thirty-four guns be
able to silence the guns of the enemy? The
effect of the shot thrown against Fort Pulaski
at distance Of three-fourtls OF mile is good
data. The first days fire cracked and crum-
bled the masonry. When the white flag was
raised the wall was ruin. II this was ac-
compished at such distance il is reasonable
to conclude that the l5-inch guns at one third
the distance will be able TO breach the walls of
Sumter. Against earthworks no experiment
has been made except at Fort McAllister.
There the fire was desperate. The twenty
five feet embankments were badly torn. One
gun was dismounted and this at the distance
of mile, Earthworks are stronger defense
than masonry. They can be repaired at night
and be made almost good as new. But the
feet will not be compelled to silence them be-
fore reaching Charleston. They can be pass
ed with impuuity, at least such is the supposi-
tion.l But when there is SO much that is new
and untried-new guns, great guns, new ma
chinery, new defensive and offensive applian-
ces, no satisfactory conclusions can be arrived
at. We must wait for the trial.
II will be an all important one. The accounts
of the engagement will be read with absorb
ing interest, not only by the great public, but
by artllerists, ordnance officers, boards of Ad-
miralty, mechanicans, workers in iron and
steel, founders, engineers, shipbuiders, ,philoso-
pliers and historians.
The little unprtending fleet, which, as you
look upon it, seems just ready to go to the bot
tom, Is riding at anchor tonight. Tomorrow
it will be on its way to the rendezvous. The
ardent hopes and expectations of millions of
loyal hearts will accompany 1t. In all untried
experiments there is possibility of failure; but
there are also probabilities Of success. So we
walt IN hope. Looking across the peaceful wa
ters the bay see the towering masts of the
Wabash-a splendid specimen OF the naval ar
chitecture, of an age almost past away-gone
never to return. Around her are little specks
not much larger, TO appearance, than the paint
ed buoys which mark the channel to the sea.
They are concentrated thoughts of all the
conflicts of time. between man and man-the
first iron-clad fleet the world has seen, to be
nsed few hours hence in righteous cause.
Far-far down the stream of time will roll its
mighty thnnders.
HILTcN HEAD. APRIL l, 1S63