240. Surveyor's square measures are used chiefly in government surveys. TABLE. 625 square links (sq. 1.) make 1 square rod (sq. rd.) A cubic inch is a cube, each edge of which is 1 in. in length. A cubic foot is a cube, each edge of which is 1 ft. in length. 243. Cubic measures are used in measuring solids. TABLE. 1728 cubic inches (cu. in.) make 1 cubic foot (cu. ft.) A cord of wood is a pile 8 ft. long, 4 ft. wide, and 4 ft. high; and a cord foot is one foot in length of such a pile; hence, 1 cord foot = 16 cu. ft. A cord contains 128 cu. ft. Oral Exercises. Read the following, calling the missing numbers: = 1. 2 feet ( ) in.; 6 ft. () in.; 3 ft. () in. () ft.; 30 in. ) yd., =( ) in. 33 yd. =( )rd. () in. 6. 400 chains() miles, =( ) rd.; 7. ) ft., 144 mile () rd.; 8 yd. =() ft.; 7 ft. 8. 3 chains( ) links, =( ) rd., = ( ) yd., = ( )ft. 9. 2 sq. feet() sq. in.; 5 sq. ft. () sq. in. 10. 1440 sq. in. =( ) sq. ft.; 432 sq. in. =( 244. Capacity signifies extent of room or space. 245. Measures of capacity are of two kinds: measures of quids, and measures of dry substances. 246. Liquid measures are used in measuring liquids. The gallon contains 231 cubic inches. The barrel and hogshead have no fixed capacity, but vary when used for commercial purposes. Usually, especially in measuring cisterns, 1 barrel (bar.) = 311⁄2 galls., and 1 hogshead (hhd) : galls. 63 247. Apothecaries' fluid measure is used for measuring all liquids that enter into the composition of medical prescriptions. Table. 60 minims (m.) make 1 fluid drachm (f3.) NOTES.-1. Cong. is an abbreviation for congiarium, the Latin for gallon; O. is the initial of octans, the Latin for one-eighth, the pint being one-eighth of a gallon. 2. For ordinary purposes, 1 tea-cup =2 wine-glasses spoons = 32 tea-spoons 4 fz. = 8 table 248. Dry measures are used for measuring quantities that are not liquid; such as grain, potatoes, etc. The bushel is 8 in. deep, and 18 in. in diameter, and contains 2150.4 cubic inches. This table is of but little practical use, as dry articles are now generally bought and sold by weight. See Art. 474. Oral Exercises. Read the following, calling the missing numbers: 1. 40 gills() pt., ( ) qt.; 9 pt. =( ) gills. 2. 8 gallons = ( ) qt., = ( ) pt., = ( ) gills. 3. 24 pints() qt., = ( ) gal.; 18 qt. =( ) gal. 4. 120 minims() f5; 5 f. 3() f. 3 =( ) m. 5. 5 cong. ( ) O., = ( 6. 252 f. 3( ) f. 3 = ( ) f. 3; 48 f. 3 = ( )0. ) O.; 70 O. = () cong. ) pks.; 32 qt. =( ) pks. 8. 20 quarts = ( ) pt., = ( ) pks. ; 2 bu. =( ) pks. MEASURES OF WEIGHT. 249. Weight is the measure of the force of gravity, which draws bodies toward the center of the earth. 250. Troy weight is used in weighing precious stones, gold, silver, etc. 24 grains (gr.) make 1 pennyweight (pwt.) 20 pennyweights 12 ounces TABLE. The standard unit of weight in the United States is the troy pound of the Mint, which is identical with the troy pound of Great Britain. 251. Avoirdupois weight is used for all the ordinary purposes of weighing. In weighing some of the coarser articles, as iron and coal at the mines, and goods on which duties are paid at the U. S. Custom Houses, the long ton of 2240 pounds is still used. 253. Apothecaries' weight is used in prescribing and in compounding dry medicines. The pound, ounce, and grain of this weight are the same as those of Troy weight. 6. 5 pounds=( ) oz., =( ) pwt.; 33 oz. =( ) pwt. =( ) oz., () cwt., () b.; 120 pwt. () lb. ; 5 lb. 8. 7 tons 10. 3 cwt. ( ) Hb. ; 2} T. = ( ) cwt.; 5 = ( ) oz. 17 T. () b. lb. = ( ) oz. MEASURES OF TIME. 254. Time is a limited portion of duration. TABLE, 60 seconds (sec.) make 1 minute (min.) 255. The solar day is the interval of time between two successive passages of the sun over the same meridian. 256. The mean solar day is the average length of all the solar days in the year. Its duration is 24 hours, and it is the principal unit of time measures. |