struck, thereby communicating the flame to the bursting charge.
Of course, these were not always sure.
Whether the one or the other form of fuse was used, depended on the purpose of the firing.
If against troops, it was desirable to cause the shell to burst in their midst, and not to allow it to penetrate the ground.
If desired for the destruction of earthworks or magazines, it had to be exploded after the penetration.
In the former case the time-fuse, and in the latter the percussion-fuse was used.
At Fort Scott
, near Washington
, in October, 1863, an experiment was tried to test the value of spherical case-shot when fired from mortars.
The 10-inch shell was filled with 12-pound canister-shot, and the bursting charge was loose.
The capacity of the shell was thirty-eight of that size balls, but twenty-seven only were used.
They were inserted through the fuse-hole, and two and a half pounds of bursting powder placed on top of them.
The shell weighed ninety pounds and each of the balls forty-three hundredths of a pound, making a total weight of about one hundred and four pounds. A charge of one pound six ounces of mortarpowder gave a range of eight hundred yards with a time of flight of thirteen seconds.
The experiments showed that the fragments scattered a great deal and the balls had ample power to kill.
They penetrated the ground from three to seven inches in a turf where, when thrown by a man with his whole strength, they entered less than one inch. A little calculation showed that the velocity must have been over two hundred feet per second, and as the projectiles weighed nearly half a pound each, there was easily sufficient force to disable a man or a beast.
The practicability of the shot having been fully determined, a field-trial was given which proved conclusive.
The projectile was used in the battle of the Petersburg
mine, where General Hunt
's orders for the artillery were to use every exertion to quiet the batteries of the foe bearing on