, 1862-03-05

An expedition is expected to leave Cairo for
New Orleans. Though not strictly on COM
mercla1 el1and, 1t bears with it the interests Of
commerce for long years to come It carries 4
heavy cargo on consignment, which will be
promptly delivered, and Jet there are no terms
Of sale. It is ecekinga a market and yet will
make market for itself. It Will strictly follow
the law of supply and demand, and yet will
deliver lis freight irrespective Of orders from
those who receive it, and will only be limited
in the amount supplied by the expressed nn-
Willingness OF those On slorc to take more,
All attempts to close the ports against the
feet will fail; it was tried in the Cumberland
and the Tennessee, and fell short by Foote-
Commodore Foote-whosc gun boats and
mortar boats will go through to the Crescent
City withoutany doubt, when once under way.
We have already devoted some space to de-
scr1pflon OF the gunboats, The mortar boats
are yet untried By any actual enlargement on
the Mississippi, and VIC have called in the aid
Of the engraver the better to present to our
readers the pecnliarity which they offer among
other ordnance, and tie features that make
them desirable under circumstances when 9th
-
advantage This was shown On the Cunbcr-
land, where our gunboats were called to cope
with the frowniDg batteries Of Fort Done1son,
from their position high above the stream.
Our heavy sixty-fours could then only be
worked with difficulty, requiring an elevation
that 5mPeded their efiiciency-to raise their
shell and round shot one hundred feet or more
above the surface Of the stream. The cannon
is emphatically Straightforward in its mode Of
operations, and asks a range Of its own.
1t docs not equally well do its work when its
point Of aim lies so FIR above its own plane.
Just this latter is the use Of the mortar. II
is always the happicst in just this class of
work
And this will be best shown by the cut VIC
give above. The mortar turning on Its mas
slVe bearings can be adjusted at an angle
which lifts its ponderous missile into the air
instead Of hurling it forward as from the can
mons month. The above sketch Of mortar
we copy from Scott's Military Dictionary.
This, which We thus represent, is the 13-inth
siege mortar, whose immense bulk Of metal
has on several recent occasions attracted tile
admiration Of our citizens, On tie passage of
these weapons Of VIII through this city from
pittsburgh 10 Cairo, each mortar requiring for
Its transportation platform cur.
There arc thlrty-eight Of these mortars in
Commodore Foote'S fleet, each mounted or
its own boat, which is little more than iloat-
ing raft Of strongly braced plank and timbcrs.
About each rises an enclosure Of boiler iron
about scycn feet high for the protection Of the
artillcrists from sharp shooters The mortar
boats arc towed by tugs or by transport
steamers, 10 which latter the artllerists retreat
when the mortar is fired, the terrific con
cussion being too much to be safely
endured. These mortars throw the two
hundred-pound shell, the elevation and
distance accurately depending upon the
strength Of the charge used. Thus twenty
pounds Of powder will give range Of 1926
yards, or about Is miles. This fearful mis-
sile has 4 bursting charge Of powder, and is
so constructed as to be itself discharged by
means Of "timc fuze," prepared so that at
discretion the artillerist may cause the missile