r small holes appear on the surface, strike the point of the
hammer into them, and ascertain their depth with the searcher. If the
depth of the cavity exceeds 0.2 inch, the shot shall be rejected; it
shall also be rejected if any attempt is made to conceal defects by
plugging or filling holes in any mode whatever.

72. The shot must pass in every direction through the large gauge, and
not at all through the small one; the calipers and scale will
determine exactly the difference of diameters of the same projectile.

73. The ring and cylinder gauges shall be examined before each
inspection, and when found to have enlarged 0.01 of an inch, must be
laid aside and marked as unserviceable.

74. The shot are next to be passed through the cylinder-gauge, placed
at an inclination of about two inches between the ends, and supported
in such a manner as to be easily turned from time to time, to prevent
its being worn in furrows. Shot which slide or stick in the cylinder
shall be rejected; the latter must be pushed out from the lower end of
the cylinder with a wooden rammer.

[Illustration: PRINCIPAL INSPECTING INSTRUMENTS FOR SHELLS D. Van
Nostrand Publisher. Julius Bien, pr.]

75. The next proof of shot is to drop a few taken indiscriminately
from the lot under inspection from a height of twenty feet on a solid
platform of iron, or roll them down an inclined plane of the same
height against a mass of iron; after which they are again examined for
defects of metal.

76. The average weight of shot shall be determined by weighing at
least three parcels, of from 20 to 50 each, taken indiscriminately
from the lot. As many of the lightest shall be weighed separately as
the inspecting officer may deem necessary, and all found to fall below
the least weight allowed in the annexed table of the dimensions of
shot and shells shall be rejected. Shot made of charcoal iron will be
stamped with a * or "burr" near the gate.

SHELLS.

77. Shells should be cast on a half-inch hollow spindle, to allow the
gas to pass freely from the core; the fuze-hole would then be
sufficiently large to admit the gauge for thickness before the shells
leave the foundry.

78. INSPECTING INSTRUMENTS.--In addition to the instruments for shot,
there will be required calipers with steel points for measuring the
thickness of the shell at points on the great circle at right angles
with the axis of the fuze-hole; gauges for the thickness at and
opposite the fuz