The following table shows the true weight of leaden spheres, the dimensions being taken in inches.
| Weight. | Diameter. | Weight. | Diameter. | Weight. | Diameter. |
| 1 dram | ·264 | 1 oz. | ·664 | 1 lb. | 1·672 |
| 2 drams | ·332 | 2 " | ·836 | 1¼ " | 1·8 |
| 4 " | ·418 | 4 " | 1·056 | 1½ " | 1·91 |
| 8 " | ·528 | 8 " | 1·328 | 1¾ " | 2·02 |
| 12 " | ·604 | 12 " | 1·52 | 2 " | 2·112 |
And 2⁄3 of the above numbers multiplied by 8, give the correct names for rockets in eighths of an inch.
Required the true size of a half-pounder.
(1·328 × 2 × 8)/3 = 7·08.
A trifle above 7⁄8, as before stated.
A cast-iron ball 6 inches in diameter weighs 30lb.
Cast iron is about 40⁄63 the weight of lead.
5280 feet = 1 mile; 3280 feet = 1 kilometre.