ch holding two eight-inch guns; these again with
four smaller, containing four six-inch guns, and you have power of
offense nearly equal to your protection. Loosely speaking, a modern
gun-projectile will, at short range, pierce steel equal to itself in
cross-section, and from an elevated muzzle will travel as many miles as
this cross-section measures in inches. Placed upon an outlying shoal,
this box with its guns would make an efficient fortress, but would lack
the advantage of being able to move and choose position.

Build underneath and each way from the ends of the box a cellular hull
to float it; place within it, and below the box, magazines, boilers,
and engines; construct above, between the turrets, a lighter
superstructure to hold additional quick-fire guns and torpedo-tubes;
cap the whole with a military mast supporting fighting-tops, and
containing an armored conning-tower in its base; man and equip,
provision and coal the fabric, and you can go to sea, confident of your
ability to destroy everything that floats, except icebergs and other
battle-ships.

Of these essentials was the first-class coast-defense battle-ship
_Argyll_. She was of ten thousand tons displacement, and was propelled
by twin screws which received ten thousand horse-power from twin
engines placed below the water-line. Three long tubes--one fixed in the
stem, two movable in the superstructure--could launch Whitehead
torpedoes,--mechanical fish carrying two hundred and twenty pounds of
guncotton in their heads,--which sought in the water a twenty-foot
depth, and hurried where pointed at a thirty-knot rate of speed. Their
impact below the water-line was deadly, and only equaled in effect by
the work of the ram-bow, the blow of the ship as a whole--the last
glorious, suicidal charge on an enemy that had dismounted the guns, if
such could happen.

Besides her thirteen-, eight-, and six-inch guns, she carried a
secondary quick-fire battery of twenty six-pounders, four one-pounders,
and four Gatling guns distributed about the superstructure and in the
fighting-tops. The peculiar efficacy of this battery lay in its menace
to threatening torpedo-boats, and its hostility to range-finders,
big-gun sights, and opposing gunners. A torpedo-boat, receiving the
full attention of her quick-fire battery, could be disintegrated and
sunk in a yeasty froth raised by the rain of projectiles long before
she could come within range of torpedo action; while a si