r three inches into the armor and do not go through the plate. They
pass through wrought iron tubes in the backing and set up with cups,
washers and nuts against the inner skin of the ship.

At steel works where plates for our new navy are being manufactured,
there are inspectors who look after the government's interests.
Officers of the navy are detailed for this work, and their duty is to
watch the manufacture of plates through each part of the process and
to see that the conditions of the specifications and contract are
complied with.

The inspection and testing of armor plates consists in examining them
for pits, scales, laminations, forging cracks, etc., in determining
the chemical analysis of specimens taken from different parts, in
determining the physical qualities of specimens taken longitudinally
and transversely, and the ballistic test. Specifications for these
different tests are constantly undergoing change, and it would be
impossible to state, with exactness, what the requirements are or will
be in the near future. The ballistic test is the important one, and is
made by taking one plate of a group and subjecting it to the fire of a
suitable gun. The other tests are simply to insure, as far as
practicable, that all the other plates of the group are similar to and
are capable of standing as severe a ballistic test as the test plate.

The following will give an idea of the ballistic test as prescribed by
the Bureau of Ordnance, Navy Department. The test plate, irrespective
of its thickness, is to be backed by thirty-six inches of oak or other
substantial wood. Near the middle region of the plate an equilateral
triangle will be marked, each side of which will be three and one-half
calibers long. The lower side of the triangle will be horizontal.
Three shots will be fired, the points of impact being as near as
possible the extremities of the triangle. The velocity of the shot
will be such as to give the projectile sufficient energy to just pass
through a wrought iron plate of equal thickness to the test plate, and
through its wood backing. The velocity is calculated by the Gavre
formula:

a
V squared = --- { 3507 E squared x 2265464 e^{1.4} }
w

[TEX: V^2 = \frac{a}{w} \{ 3507 \ E^2 \times 2265464 \ e^{1.4} \}]

V = the velocity of the projectile in feet per second.
a = the diameter of the projectile in inches.
w = the weight of the projectile in pounds.
E =