as much as 3 lbs. of gunpowder, these quantities
were compared together on the 22nd of February. The guns employed to
discharge the gunpowder were a 12-lb. brass howitzer, a 24-lb.
cast-iron howitzer, and the long 18-pounder employed at the South
Foreland. The result was, that the 24-lb. howitzer, firing 3 lbs. of
gunpowder, had a slight advantage over 1 lb. of gun-cotton detonated
in the open; while the 12-lb. howitzer and the 18-pounder were both
beaten by the gun-cotton. On the end of May, on the other hand, the
gun-cotton is reported as having been beaten by all the guns.

Meanwhile, the parabolic-muzzle gun, expressly intended for
fog-signalling, was pushed rapidly forward, and on March 22 and 23,
1876, its power was tested at Shoeburyness. Pitted against it were a
16-pounder, a 5.5-inch howitzer, 1.5 lb. of gun-cotton detonated in
the focus of a reflector (see annexed figure), and 1.5 lb. of
gun-cotton detonated in free air. On this occasion nineteen different
series of experiments were made, when the new experimental gun, firing
a 3-lb. charge, demonstrated its superiority over all guns previously
employed to fire the same charge. As regards the comparative merits
of the gun-cotton fired in the open, and the gunpowder fired from the
new gun, the mean values of their sounds were the same. Fired in the
focus of the reflector, the gun-cotton clearly dominated over all the
other sound-producers. [Footnote: The reflector was fractured by the
explosion, but it did good service afterwards.]

FIG. 10.

Gun-cotton Slab (1.5 lb.) Detonated in the Focus of a Cast-iron
Reflector.

The whole of the observations here referred to were embraced by an
angle of about 70 deg., of which 50' lay on the one side and 20 deg. on the
other side of the line of fire. The shots were heard by eleven
observers on board the 'Galatea,' which took up positions varying from
2 miles to 13.5 miles from the firing-point. In all these
observations, the reinforcing action of the reflector, and of the
parabolic muzzle of the gun, came into play. But the reinforcement of
the sound in one direction implies its withdrawal from some other
direction, and accordingly it was found that at a distance of 5.25
miles from the firing-point, and on a line including nearly an angle
of 90 deg. with the line of fire, the gun-cotton in the open beat the new
gun; while behind the station, at distances of 8.5 miles and 13.5
miles respectively, the g