WEIGHT AND BULK OF MATERIALS.
The weight of a cubic foot of any material is its specific gravity multiplied by 62·425, or the weight of a cubic foot of water in pounds. To find the specific gravity of a stone, divide its weight in air by loss of weight in water of temperature of 60° F. = specific gravity.
Thus:
| Quartz crystal weighs in | air | 293·7 | grains |
| ” ” | water | 180·1 | ” ” |
| ------ | |||
| Loss in weight | 113·6 | ” ” |
Then:
293·7⁄113·6 = 2·59 = Specific gravity of quartz.
One ton of quartz when solid occupies 13 cubic feet, but when broken, about 20. Rocks when solid, as compared to the same when broken, usually increase in volume in the ratio of 1 to 1·5 or 1 to 1·18, the increase depending on size and form of fragments.
A dwt. of gold in a cwt. of ore = 1 oz. of gold per ton of ore.
For approximate calculation a grain of gold = two pence, and a dwt., four shillings.
In the following table of the chemical elements the standard of sp. gr. is hydrogen for the gaseous elements (hydrogen, oxygen, &c.) and water for the others.