Example. How many cubic feet of sea water will weigh a ton?

Divide 2240 lbs. (1 ton) by 64 lbs.

{ _8)2240
64 { ——
{ 8) 280
——
Ans. 35

Example. What is the weight of a cubic foot of wrought iron?

62·5 lbs.
7·69 sp. gravity.
——–
5625
3750
4375
———-
Answer, 480·625 lbs.

480 lbs. in practice is the weight of 1 cubic foot of wrought iron.

Note.—35 cubic feet of sea water is accounted to be a ton, as in sea water ballast for steamers, and in calculating displacement of ships.

Example. What is the average weight of a cubic foot of Bituminous coal?

1·256 sp. gravity.
62·5 lbs.
——–
6280
2512
7536
———–
Answer, 78·5000 lbs.