| has gloss | eng: The Jolly balance is an instrument for the determination of specific gravities. It consists essentially of a spring fastened at the top to a movable arm. At the lower end, the spring is provided with two small pans, one suspended beneath the other. The lower pan is kept always immersed to the same depth in water, while the other one hangs in the air. On the upright standard behind the spiral is a mirror on which is engraved or painted a scale of equal parts. The specific gravity of an object, typically a solid, is determined by noting the amount of lengthening of the spring when the object is resting in the upper pan in air (w), and the amount when it is in the lower pan and immersed in water (w). The specific gravity is then w / (w - w). |
