THE WISCONSIN FARMER.



inder. Then another bar is coiled around this
coil and welded down in like manner; and so
the process is repeated until the required thick-
ness of wall is attained.  By this means he
gets a maximum    strength with minimum
weighlt.
  - IVLen completed, the Armstrong gun con-
sists of three distinct pieces-the barrel, the
breech-serew, and the vent-piece. The vent-
piece is entirely detached from the gun, lifts
in and out of the breech, and contains the vent.
The breech-screw is worked by a handle and
serves to wedge the vent-piece against the side
of the chamber, thereby preventing its being
blown out by the explosion of the charge."
  The comparative lightness of this gun is ap-
parent from the fact that a 110-pounder Arm-
strong gun weighs only 56 cwt., while the cast
iron 6s-pounder service gun weighs 95 cwt.
  The eonical-pointed shot and shell used in
these guns with so much effect are likewise in-
ventions of Sir William Armstrong. A slab
of solid wrought iron several inches thick, but
with a terrible looking hole directly through
it, is exhibited here in evidence of their resist-
less power.
  The Whitiwsotth gun differs front the Arms-
strong gun in the following particulars:
  1. The ? 1,rc of the barrel is hexagonal, in-
stead of round.            b
  2. It is not made on tihe coil principle, but
forged i on (ie piece.
  ^. The lrecch opens sidew ise, on a hinge,
after the ltre ch-strew is loosened.
  The shot hlve the six-sided form to corres-
pond witlh 'ihe  arrel. and are not coated with
lead. w hich last circntustarce is thought to
costt:!1'1 III i iinorti.t t oljection. The charge
is enclo, I mt a tin case. instead of flannel, as
ordinarily. -) a to prevent the escape of gas.
Amo-nt Of''segn. one-q1uarter of the weight
of prjec'ile. Fecw guns have supertor power.
The one here exhibited, with an elevation of
three degrees, threw a ball a dlistance of five
miles. three thousand six hundred yards!
  The 'Mereey Steel and Iron Co., Liverpool,
exhibit very powerful breech-loadintz guns



which were cast hollow-the inside and outside
of metal thus being allowed to cool equally.
This one, called the " Prince Alfred," has a 10
inch bore and throws a projectile of 500 to 600
pounds weight.  Demolished targets of thick
wrought iron, backed by 18 inches of solid
teak (hardest kind of ship timber) are proof
of its power. Indeed, guns of smaller calibre
made on this principle have been repeatedly
discharged with the barrel nearly full of solid
shot, a solid cylinder of iron rammed down
upon them, and the projecting end placed
against a solid rock, so that the gun itself was
fired from the shot-and yet without bursting!
  In the class of Shot, Shell, Fuses, etc., the
Secretary of State for War makes a very ex-
tensive and interesting exhibition.
  One of the shells, "1 Mallett's Monster," is
8 feet in diameter and weighs 1 ton and 2 cwt
A monster of this class, recently fired at Wool-
wich, described a magnificent circle about
three-quarters of a mile high and penetrated
the earth, when it fell, to the depth of eight-
een feet!  If Uncle Sam could only get the
Southern Rebellion concentrated in one small
point and then let a few of these shells fall
upon it, the country would probably be quiet
for at least thirty years longer.

            NAVAL ARCHltTECTUr.E.
  In this branch of the British Department we
find a most interesting series of models illus-
trative of the progress of shipbuilding from
the earliest times to the present-including the
famous iron-clads " Warrior," " Minotaur,"
and ' Northumberland."  Ten years ago this
display would have been worth the careful ex-
amination of the naval architects of the world,
but since the building of our own matchless
Yankee irOn-eladF, there is but little in the
tear part of it that is of more than mere his-
toric interest. The merchant ships are repre-
sented by some of the finest modlels of the
world.
  In the yncht line, Amierica is confessedly
alead, and her models are being everywhere



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