nt of one found in the trenches
at Sebastopol.

[Illustration: Fig. 20]

The use of these guns in the siege was by no means satisfactory, giving
neither precision of fire nor extraordinary range, while the gun more
often failed by bursting than other types. The principle, however, met
with favor and was studied and improved upon.

Another method of applying the rifle principle to heavy guns consisted
in casting a segment of a sphere (nearly) on the side of the cylinder
part of the shot with corresponding grooves in the bore of the gun,
making about one turn in twenty feet. It is somewhat like the principle
of the solid musket ball, Fig. 7 with a difference in the shape of the
projections, as shown in the annexed Fig. 21, giving the form and size
(nearly) of the shot.

Guns of this pattern were adopted for many of the gunboats fitted out
by France for operations in the Baltic in 1856, some with four and
others with two guns each.

[Illustration: Fig. 21]

[Illustration: Fig. 22]

The bore of the gun had a circular section of 6-1/2" diameter with two
grooves cut in it, as shown in Fig. 22, which in the length of the bore
had a twist equal to one turn in six meters.

Figures 23 and 24 represent cast iron shot "of very peculiar shape,
intended apparently, as a substitute for the rifle groove. They were
cylinders of about four inches diameter, with a flattened spherical
head from which three spiral openings communicate with the open
interior of the cylinder. The cylindrical part was formed with
grooves...."

[Illustration: Fig. 23]

[Illustration: Fig. 24]

The Modern Type of Gun

From these earliest examples the development of artillery has been
gradual until the present day of the built-up gun with an energy and
range undreamed of in the earlier days. The built-up gun of today has
attained to a calibre of 16 inches, a length of nearly 50 feet, a weight
of 124 tons, and an extreme range at 42 deg. elevation of 20.9 miles with
a maximum height of trajectory of over 5-3/4 miles. The projectile, too,
has increased in size from a few pounds to the one ton or 2,240-pound
mass used in the above gun. The energy imparted to it at the muzzle
amounts to 6,408-foot tons assuring a penetration at the muzzle of 33.8
inches of steel, or at 3,500 yards of 27.5 inches, the muzzle velocity
being 1,975-foot-seconds and powder charge 640 pounds of smokeless. The
maximum pressure in the powder chamber allowed is 37,000