manufacture and testing of armor. It would be interesting to wade
through the history of armor, studying each little step in its
development, but we shall simply take a hasty glance at the past, and
then devote our attention to modern armor and its immediate future.

Modern armor has arrived at its present state of development through a
long series of experiments. These experiments have been conducted with
great care and skill, and have been varied from time to time as the
improvements in the manufacture of materials have developed, and as
the physical laws connected with the subject have been better
understood. There has been very little war experience to draw from,
and hence about all that is now known has been acquired in peaceful
experiments.

The fundamental object to be obtained by the use of armor is to keep
out the enemy's shot, and thus protect from destruction the vulnerable
things that may be behind it. The first serious effort to do this
dates with the introduction of iron armor. With this form of armor we
have had a small amount of war experience. The combat of the Monitor
and Merrimac, in Hampton Roads, in May, 1862, not only marked an epoch
in the development of models of fighting ships, but also marked one in
the use of armor. The Monitor's turret was composed of nine one-inch
plates of wrought iron, bolted together. Plates built in this manner
form what is known as laminated armor. (See Fig. 1.) The side armor of
the hull was composed of four one-inch plates. The Merrimac's casemate
was composed of four one-inch plates or two two-inch plates backed by
oak. The later monitors had laminated armor composed of one-inch
plates. The foregoing, with the Albemarle and Tennessee rams under the
Confederate flag, are about the sum of our practical experience in the
use of armor.