| feet. | inches. | ||
| Length | at top | 26 | |
| ” | at bottom | 23 | |
| Depth | 2 | 8 | |
| Width | 2 | 3 |
The common pontoons will support a weight of 4 or 5000 pounds. They are generally placed, in forming a bridge, about their own width asunder. See the word [Bridge].
PORTFIRES.
Composition. Saltpetre, 60 parts; sulphur, 40 parts; mealed powder, 20 parts. Length of each, 16½ inches.
One will burn from 12 to 15 minutes.
Weight of one dozen, 3 lbs. 12 oz.
Portfires were made at Gibraltar in the following manner; two ounces of nitre was dissolved in a gallon of water, and sheets of soft brown paper dipped in the solution: these when dry were rolled up to about the size of common portfires.
PROVISIONS.—See the word [Ration].
PROOF—of ordnance.
All natures of ordnance undergo several kinds of proof before they are received into his Majesty’s service; viz. 1st, They are guaged as to their several dimensions, internal and external, as to the justness of the position of the bore, the chamber, the vent, the trunnions, &c.