Meaning of "Specific gravity"

The ratio of the weight of a given volume of any substance to the weight of an equal volume of distilled water, and is found by dividing the first weight by the second. Since the distilled water weights approximately 62.4 pounds per cubic foot, any substance, a cubic foot of which weighs less than this, has a specific gravity of less than one, and will float on water. Any substance of greater weight per cubic foot has a specific gravity of more than one and will sink>

Specific gravity Meaning of