A powder barrel is a common barrel, filled with powder, to roll from the top of a breach, or upon the head of a sap from the glacis. The barrel contains from 100 to 200 pounds of powder, and is covered with a cloth. A hole is made at each end, in which a fuse may be fixed, of such a size, that the fire may be communicated to the powder, at the moment when the barrel, rolled from the top of the breach, is met by the troops mounting to the assault.
English writers state the diameter of powder barrels at 16 inches, and 30 or 32 inches in length, and capable of holding 100 pounds of powder. The quantity of powder put into them is 90 lbs; into a half-barrel, 45 lbs; and into a quarter-barrel, used for rifle powder, only 221/2 lbs. This proportion leaves a space for the powder to separate when rolled, or otherwise it would always be in lumps, and liable thereby to damage.
Sec. XIII. Of the Burning or Illuminating Barrel.
This barrel differs from the thundering barrel, which we shall describe in the following section, only in having no grenades; and when it is placed upon a glacis, it lights up or discovers the works of the besieger. It has a fuse in only one of its ends.
When shavings are boiled in the composition for links and fascines, or of tourteaux, and arranged layer by layer, scattering, over each stratum, some priming-powder, the combustion must be rapid, when the barrel is set on fire.
Fire barrels, we may observe, are of different kinds. Some are mounted on wheels, filled with composition, and intermixed with loaded grenades, and their outsides full of sharp spikes. Some are placed under ground, and have the effect of small mines; and others, as the kind we have mentioned, are used to roll down a breach to prevent the entrance of the enemy. The following composition has been used for the same purpose.
Composition for Fire-Barrels.
| Grained powder, | 30 | lbs. |
| Pitch, | 12 | —– |
| Saltpetre, | 6 | —– |
| Tallow, | 3 | —– |
Sec. XIV. Of the Thundering Barrel.
This is employed for the same purpose as the preceding, or to light up the works of the besieger at the foot of the glacis. It has the same dimensions with the other, but has no cover. It is filled with chips, (dipped into the composition of the tourteaux), which are arranged in layers, putting, between each layer, meal-powder, and grenades, furnished with their fuses, or with pieces of musket barrels. The first and last layers are made with tow, boiled in the carcass composition. The barrel being filled, it is then closed and primed in the same way as the powder barrel, with a bomb fuse at each end. Holes are made along the barrel to assist the combustion. Grenades are employed in particular to prevent the approach of persons to extinguish the flame.