The Jolly balance is an instrument for determining specific gravities. Invented by the German physicist

Philipp von Jolly Johann Philipp Gustav von Jolly (26 September 1809 – 24 December 1884) 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. A ...

in 1864, it consists of a

spring Spring(s) may refer to: Common uses * Spring (season) Spring, also known as springtime, is one of the four temperate seasons, succeeding winter and preceding summer. There are various technical definitions of spring, but local usage of ...

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 immersed to the same depth in water, while the other one hangs in the air. On the upright stand behind the spring is a mirror on which is engraved or painted a scale of equal parts. The specific gravity of an object, typically a

solid Solid is one of the four fundamental states of matter (the others being liquid, gas, and plasma). The molecules in a solid are closely packed together and contain the least amount of kinetic energy. A solid is characterized by structural ...

, is determined by noting how much the spring lengthens when the object is resting in the upper pan in air (

w

), and then when the object is moved to the lower pan and immersed in water (

w'

). The specific gravity is

\frac

Notes

References

* Weighing instruments {{Physics-stub

See also

Notes

References