hell-guns": the 9-, 10-,
11-, and 15-inch iron smoothbores. There were also 8-inch guns of 55
and 63 "hundredweight" (the contemporary naval nomenclature), and four
sizes of 32-pounders ranging from 27 to 57 hundredweight. The heavier
guns took more powder and got slightly longer ranges. Many naval guns
of the period are characterized by a hole in the cascabel, through
which the breeching tackle was run to check recoil. The Navy also had
a 13-inch mortar, mounted aboard ship on a revolving circular
platform. Landing parties were equipped with 12- or 24-pounder
howitzers either on boat carriages (a flat bed something like a mortar
bed) or on three-wheeled "field" carriages.

RIFLING

Rifling, by imparting a spin to the projectile as it travels along the
spiral grooves in the bore, permits the use of a long projectile and
ensures its flight point first, with great increase in accuracy. The
longer projectile, being both heavier and more streamlined than round
shot of the same caliber, also has a greater striking energy.

Though Benjamin Robins was probably the first to give sound reasons,
the fact that rifling was helpful had been known a long time. A 1542
barrel at Woolwich has six fine spiral grooves in the bore. Straight
grooving had been applied to small arms as early as 1480, and during
the 1500's straight grooving of musket bores was extensively
practiced. Probably, rifling evolved from the early observation of the
feathers on an arrow--and from the practical results of cutting
channels in a musket, originally to reduce fouling, then because it
was found to improve accuracy of the shot. Rifled small-arm efficiency
was clearly shown at Kings Mountain during the American Revolution.

In spite of earlier experiments, however, it was not until the 1840's
that attempts to rifle cannon could be called successful. In 1846,
Major Cavelli in Italy and Baron Wahrendorff in Germany independently
produced rifled iron breech-loading cannon. The Cavelli gun had two
spiral grooves into which fitted the 1/4-inch projecting lugs of a
long projectile (fig. 12a). Other attempts at what might be called
rifling were Lancaster's elliptical-bore gun and the later development
of a spiraling hexagonal-bore by Joseph Whitworth (fig. 12b). The
English Whitworth was used by Confederate artillery. It was an
efficient piece, though subject to easy fouling that made it
dangerous.

Then, in 1855, England's Lord Armstrong designed a rifled b