eld in
place by a plain ball, G, near the axis of the fuse and by a safety pellet,
H. On first movement in the gun, this latter by inertia shears a suspending
wire and leaves the ball free to escape above it, which it does by
centrifugal force, leaving the magazine striker, D, free to fire itself by
momentum on the needle shown above it, on impact. There is a second safety
arrangement, not shown in the figure, consisting of a cross pin, held by a
weak spiral spring, which is compressed by centrifugal force during flight,
leaving the magazine pellet free to act, as above described, on impact.

The armor-piercing projectile is shown in Fig. 7. It is to be made of
forged steel, and supplied by Elswick. In appearance it very closely
resembles those fired from the 100 ton gun at Spezia, but if it is made on
the Firmini system, it will differ from it in the composition of its metal,
inasmuch as it will contain a large proportion of chromium, probably from 1
to 2 per cent., whereas an analysis of Krupp's shell gives none. In fact,
as Krupp's agent at Spezia predicted, the analysis is less instructive than
we could wish.--_The Engineer_.

* * * * *

GAS ENGINE FOR USE ON RAILROADS.

The industrial world has reason to feel considerable interest in any
economical method of traction on railways, owing to the influence which
cost of transportation has upon the price of produce. We give a description
of the gas engine invented by Mr. Emmanuel Stevens. Many experiments have
been made both at Berlin and Liege during the past few years. They all
failed, owing to the impossibility the builders encountered in securing
sufficient speed.

The Stevens engine does not present this defect, as will be seen. It has
the appearance of an ordinary street car entirely inclosed, showing none of
the machinery from without. On the interior is a Koerting gas motor of six
horse power, which is a sufficiently well known type not to require a
description. In the experiment which we saw, the motor was supplied with a
mixture of gas and air, obtained by the evaporation of naphtha. On the
shaft of the motor are fixed two pulleys of different sizes, which give the
engine two rates of speed, one of three miles and the other of 81/2 miles an
hour. Between these two pulleys is a friction socket, by which either rate
of speed may be secured.

The power is transmitted from one of the pulleys by a rubber belt to an
inter