dition for effective bursting, the lot will be
accepted.

If any of the shell fail to pass this test, the lot will be rejected.

The following extract from the "Circulars and Specifications of the
Navy Department concerning Armor Plate and Appurtenances for Vessels of
the U.S. Navy," (April 22, 1907) while pertaining to another subject,
will be pardoned if introduced here for the purpose of demonstrating
the seemingly paradoxical requirements a manufacturer is called upon to
meet:

(Par. 60.) The ballistic test for acceptance of armor shall be made as
strictly as practicable in accordance with the following tables, the
Department reserving the right to use guns of other calibres than
designated for any plate if it is deemed advisable.

In the test of armor of Class A there shall be three impacts with
striking velocities as given in the following table, capped
armor-piercing projectiles being used:

-------------+-----------+-------------+-----------
Wt. of shell| Calibre of| Thickness of| Striking
capped | gun | plates | velocity
Pounds | Inches | Inches |Ft.-seconds
-------------+-----------+-------------+-----------
105 | 6 | 5 | 1,451
105 | 6 | 6 | 1,648
105 | 6 | 7 | 1,836
165 | 7 | 6 | 1,464
165 | 7 | 7 | 1,631
165 | 7 | 8 | 1,791
260 | 8 | 7 | 1,459
260 | 8 | 8 | 1,603
260 | 8 | 9 | 1,741
510 | 10 | 9 | 1,458
510 | 10 | 10 | 1,568
510 | 10 | 11 | 1,676
870 | 12 | 11 | 1,424
870 | 12 | 12 | 1,514
-------------+-----------+-------------+-----------

The first impact shall be located near the central portion of the
plate, and the other two impacts shall be located as directed by the
Bureau; no impact, however, to be nearer another impact or an edge of
the plate than 3-1/2 calibres of the projectile used.

On these three impacts no projectile or fragment thereof shall get
entirely through the plate and backing, nor shall any through crack
develop to an edge of the plate or to another impact.