40 rods or 220 yds. = 1 furlong. = 1 mile. = 1 degree. 5 yards or 161 ft. = 1 rod or pole. 60 geo. miles NOTE.-Bowditch gives 6120 feet in a sea mile, which, if taken as the length, will make the divisions 51 feet and 5 1-10 feet for the knot and fathom. NOTE.-By these tables, land measure and artificers' work are computed. 8 cord feet or 128 cubic feet 1 cord of wood. NOTE.-A cubic foot is equal to 2200 cylindrical inches, or 3300 spherical inches, or 6600 conical inches. A cubic foot of water equals 62 lbs.; a cylindrical foot equals 49'1; a cubic inch equals 03617 lbs.; a cylindrical inch equals '02642 lbs. NOTE-The Winchester bushel (so called because the standard measures were kept at Winchester) is 18 inches diameter, and 8 inches deep, and contains 2150 42 cubic inches. MEASURES OF WEIGHT.-TROY. By which Gold, Silver, and Precious Stones are weighed. NOTE.-An ounce of gold is divided into 24 equal parts, called carats, and an ounce of silver into 20 parts, called penny weights; therefore, to distinguish fineness of metals, such gold as will abide the fire, without loss, is accounted 24 carats fine; if it lose 2 carats in trial, it is called 22 carats fine, &c. A pound of silver which loses nothing in trial is 12 ounces fine; but if it lose 3 pennyweights, it is 11 ounces 17 pennyweights fine, &c. THE RELATIVE VALUE OF TROY AND AVOIRDUPOIS WEIGHTS.* Troy lb. Avoir. lb. Avoir lb. Troy lb. 1 4 3.291 5 6 7 8 9 4.114 4.937 5.760 6.583 7.406 4 5 6 7 8 9 4.861 6.076 7.292 8.507 9.722 10.937 *By comparing the number of grains in the advoirdupois and troy pound and ounce, respectively, it appears that the toy pound is less than the avoirupois in the proportion of 14 to 17.0138; but the troy ounce is greater than the avoirdupois in the proportion of 79 to 72. Hence, the following approximating rules for changing avoirdupois weight to troy, and troy to advoirdupois, will often be found very convenient and useful. The standard U. S. gallon measures 231 cubic inches, and contains 8-3388822 pounds avoirdupois =58372-1757 grains troy, of distilled water, at its maximum density 39.83° Fahrenheit, and 30 inches barometer height. The English Imperial gallon measures 277 274 cubic inches, containing 10 lbs. avoirdupois of distilled water, weighed in air, at the temperature of 62°, the barometer at 30 inches. |