Calibre and Weight of Rockets.
TABLE II.
Of the Calibre of Rockets of a Pound weight and below.
| 16 ounces. | 19½ lines.[10] | 14 drams. | 7¼ lines. |
| 12 do. | 17 do. | 12 do. | 7 do. |
| 8 do. | 15 do. | 10 do. | 6⅓ do. |
| 7 do. | 14¾ do. | 8 do. | 6¼ do. |
| 6 do. | 14¼ do. | 6 do. | 5⅔ do. |
| 5 do. | 13 do. | 4 do. | 4½ do. |
| 4 do. | 12⅓ do. | 2 do. | 3¾ do. |
| 3 do. | 11½ do. | ||
| 2 do. | 9⅙ do. | ||
| 1 do. | 6½ do. |
The use of this table will be easily understood, for, as in the first instance, if a Rocket of 16 ounces ought to be nineteen and a-half lines in diameter, one of 12 must be 17 lines, one of 8 ounces 15 lines, one of 8 drams six and a-quarter lines; and so of the others.
If the diameter of the Rocket be given, we can as easily, by the reverse method, find the weight of the ball corresponding to that calibre. For example, if the diameter be 15 lines, it will be immediately seen, by seeking for that number in the column of lines, that it answers to a ball of eight ounces.
As the foregoing table extends only to Rockets of 16 ounces, or one pound, and from that downwards, the following will be found equally useful for those of superior dimensions.