Thus the diameter of a bullet, whereof 12 weigh a pound, is found by subtracting .3597270, a third part of the logarithm of 12, from the given logarithm .2228756, or, when the logarithm is less than the former, an unit must be added, so as to have 1.2228756, and the difference .8631486 will be the logarithm of the diameter sought, which is .7297 inches; observing that the number found will always be a decimal, when the logarithm, which is to be subtracted, is greater than that of one pound; because the divisor is greater than the dividend in this case. Hence, from the specific gravity of lead, the diameter of any bullet may be found from its given weight: for, since a cube foot weighs 11325 ounces, and 678 is to 355 as the cube 1728 of a foot, or 12 inches, is the content of the sphere, which therefore is 5929.7 ounces: and since spheres are as the cubes of their diameters; the weight 5929.7 is to 16 ounces, or 1 pound, as the cube 1728 is to the cube of the diameter of a sphere which weighs a pound; which cube therefore is 4.66263, and its root 1.6706 inches, the diameter sought. The diameter of musket bullets differs but ¹⁄₅₀th part from that of the musket bore; for if the shot but just rolls into the barrel, it is sufficient. The English allow 11 bullets in the pound for the proof of muskets, and 14 in the pound, or 29 in two pounds, for service; 17 for the proof of carbines, and 20 for service; and 28 in the pound for the proof of pistols, and 34 for service. The proof bullet of the U. S. _musket_ made at Harper’s ferry in Virginia, the barrel of which is 3 feet 8³⁄₄ inches, is _one fifteenth_ of a pound; the service ball _one nineteenth_. The _Rifle_ of Harper’s ferry, the barrel of which is 2 feet 10 inches; the proof ball is _one twenty-eighth_ of a pound; the service ball is _one thirty-secondth_ part of a pound. See GUN and RIFLE. _Hollow_ BULLETS, or shells, of a cylindrical shape. These have an opening and a fuze at the end, by which fire is communicated to the combustibles within, and an explosion takes place, similar to that occasioned by the blowing up of a mine. _Chain_ BULLETS, are two balls which are joined together by a chain, at any given distance from each other. _Branch_ BULLETS, two balls joined together by an iron bar. _Two-headed_ BULLETS, sometimes called angles, are two halves of a bullet which are kept together by means of a bar or chain. BULWARK, the ancient name for bastion or rampart, which words see. BURDEN, BURTHEN, in a general sense, implies a load or weight, supposed to be as much as a man, horse, &c. can well carry. A sound healthful man can raise a weight equal to his own, can also draw and carry 50lb. a moderate distance. An able horse can draw 350lb. though in length of time 300 is sufficient. Hence all artillery calculations are made. One horse will draw as much as 7 men, and 7 oxen will draw as much as 11 or 12 horses. Burthen likewise in a figurative sense means impost, tax, &c.