olutely identical conditions.

Our engravings show the proving grounds and the details of the
arrangements adopted for backing the plates.

Of the three plates, the Cammell was the thickest (11 in.) The steel
one was 103/4 in. in thickness, and the nickel steel 101/2 in. The last,
therefore, was at a disadvantage with respect to the two others.

The plates were arranged tangentially to an arc of a circle whose
center was occupied by the pivot of the gun, and consequently at right
angles with the latter. The piece employed was a 6 in. gun, 35
calibers in length. The distance of its muzzle from the plates
attacked was 28 ft.

[Illustration]

The charge was 44 lb. of brown prismatic powder. The projectile was a
100 lb. Holtzer shell. Under these circumstances, the initial velocity
was 2,074 ft. and the energy at the impact was 9,970,396 ft. lb.

A beginning was made by firing four shots at each plate in the
bisectrix of the corners. Then the 6 in. gun was replaced by an 8 in.
one, throwing a 209 lb. Firth projectile, with an energy at the impact
of 20,795,000 ft. lb.

Each of the plates then received in its center a final blow from this
projectile.

Our engraving represents the state of the plates after this last shot.

[Illustration: ARMORED PLATE TESTS AT ANNAPOLIS]

There is no need of being a great expert in questions of artillery to
discover on what side the superiority is found, and to see that the
Cammell plate, almost entirely in fragments, is absolutely incapable
of protection, while its two competitors are still in a state to
resist.

In one of our engravings may be seen, too, the state of the shells
after each of the three shots.

[Illustration]

The commission immediately and unanimously classified the three plates
in the following order of superiority: (1) Nickel steel; (2) all
steel; (3) compound.

This triumph of French industry merits mention so much the more in
that it was obtained in a series of experiments made in a foreign
country--that is to say, under indisputable conditions of
impartiality.-_L'Illustration._

* * * * *

HIGH EXPLOSIVES IN WARFARE.[1]

[Footnote 1: A lecture delivered before the Franklin Institute,
Philadelphia, November 28, 1890. From the _Journal_ of the Institute.]

BY COMMANDER F.M. BARBER, U.S.N.

In commencing my paper this evening I desire to call your attention to
the fact that I am dealing with a subject which,