Fig. 91.
Fig. 91.
The specific gravity is then obtained by weighing the body first in air, and then, suspended by a fibre of silk or a hair, in water, and dividing the weight in air by the difference.It is hardly necessary to say that the substance examined must be free from mixture of foreign matters, and especially from cavities that may contain air.
Note.—Hydrometersare instruments for determining the relative density of fluids;distilled wateris usually referred to as the standard of comparison. They consist usually of a bulb or float weighted at bottom so as to float upright, and having an elongated stem graduated to indicate the density of the liquid by the depth to which they sink therein.
Note.—Hydrometersare instruments for determining the relative density of fluids;distilled wateris usually referred to as the standard of comparison. They consist usually of a bulb or float weighted at bottom so as to float upright, and having an elongated stem graduated to indicate the density of the liquid by the depth to which they sink therein.