Set 4·5 on C to 0·294 on D, and over 0·625 on D read 9·56 lb. per lineal foot on C. To find the weight per square foot of sheet metal, set the weight per cubic foot of the metal (col. 1) on C to 12 on D, and ────────────┬──────────┬──────────┬──────────┬─────────── │ (1) │(2) │ (3) │ (4) │Weight in │Weight of │ (1)/(Wt. │ Weight of Metals. │ lb. per │12 cubic │of 12 cub.│ 12 │cubic ft. │in. │ in.) │cylindrical │ │ │ │ in. ────────────┼──────────┼──────────┼──────────┼─────────── Wrought iron│480 │3·33 │0·300 │2·62 Cast iron │450 │3·125 │0·320 │2·45 Cast steel │490 │3·40 │0·294 │2·68 Copper │550 │3·82 │0·262 │3·00 Aluminium │168 │1·166 │0·085 │0·915 Brass │520 │3·61 │0·277 │2·83 Lead │710 │4·93 │0·203 │3·87 Tin │462 │3·21 │0·312 │2·52 Zinc (cast) │430 │2·98 │0·335 │2·34 „ (sheet) │450 │3·125 │0·320 │2·45 ────────────┴──────────┴──────────┴──────────┴─────────── above the thickness of the plate in inches on D read weight in lb. per square foot on C. EX.—Find the weight in lb. per square foot of aluminium sheet ⅜in. thick. Set 168 on C to 12 on D, and over 0·375 on D read 5·25 lb. on C. To find the weight of pipes in lb. per lineal foot. Set mean diameter of the pipe in inches (_i.e._, internal diameter _plus_ the thickness, or external diameter _minus_ the thickness) on C to the constant given below on D, and over the thickness on D read weight in lb. per lineal foot on C. ┌────────────┬─────────────────────┬─────────────────────┐ │ Metals. │ Constant for Pipes. │Constant for Spheres.│ ├────────────┼─────────────────────┼─────────────────────┤ │Wrought iron│ 0·0955 │ 6·87 │ │Cast iron │ 0·1020 │ 7·35 │ │Steel │ 0·0936 │ 6·73 │ │Brass │ 0·0882 │ 6·35 │ │Copper │ 0·0834 │ 6·00 │ │Lead │ 0·0646 │ 4·65 │ └────────────┴─────────────────────┴─────────────────────┘ EX.—Find the weight per foot of cast-iron piping 4 in. internal diameter and ½in. thick. Set 4·5 on C to 0·102 on D, and over 0·5 on D read 22·1 lb. on C, the required weight. To find the weight in lb. of spheres or balls, given the diameter in inches. (W = 0·5236_d_^3 × wt. of 1 cub. in. of material). Set the constant for spheres (given above) on B to diameter in inches on A, and over diameter on C read weight in lb. on A.