Jolly balance
Encyclopedia
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').
The Jolly balance was invented by the German physicist Philipp von Jolly
in 1864.
Specific gravity
Specific gravity is the ratio of the density of a substance to the density of a reference substance. Apparent specific gravity is the ratio of the weight of a volume of the substance to the weight of an equal volume of the reference substance. The reference substance is nearly always water for...
. 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').
The Jolly balance was invented by the German physicist Philipp von Jolly
Philipp von Jolly
Johann Philipp Gustav von Jolly was a German physicist and mathematician.Born in Mannheim as the son of merchant Louis Jolly and Marie Eleonore Jolly, he studied science in Heidelberg, Vienna and Berlin. After his studies, he was appointed professor of mathematics in Heidelberg in 1839 and in...
in 1864.
Further reading
- See also Elementary Crystallography by William Shirley Bayley (1910), pages 192 - 193.