ClipArt ETC
"A representation of a common form of the delicate balances employed in physical and chemical researches. the beam is constructed so as to combine lightness with strength, and rests by a fine knife-edge on an agate plane. It is surmounted by a weight moving on a screw, so that the sensibility may be increased or diminished, according as weight is raised or depressed." — Chambers' Encyclopedia, 1875

Balance

"A representation of a common form of the delicate balances employed in physical and chemical researches.…