§6

Operations of Analysis.

of the lighter body in air, and the weight of theheavier body in water; then tie, by means ofthread, both bodies together, but not so closelyas to exclude the water from, or to harbourbubbles of air between them; and weigh themboth in water. Now, since the heavy body ispartly buoyed up by the lighter body, theweight of both in water will be less than theweight of the heavier body alone: subtract theformer from the latter, and add the remainder tothe weight of the lighter body in air; for thissum is the weight of a quantity of water equal inbulk to the lighter body, therefore, the weight ofthe lighter body in air must be divided by thelast mentioned sum, and the quotient will expressthe specific gravity of the lighter body. Observethe general precautions as before stated.

Example. A piece of elm being varnished, irjorder to prevent its absorbing any water, wasfound to weigh in air 920 grains. A piece oflead, which was chosen for this purpose, wasfound to weigh in water 911,7 grains. The pieceof elm and the piece of lead were tied together,and being suspended from the hook of the scaleC, &c. in the usual manner, were found toweigh in water 331,7 grains (viz.) 580 grains less