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"A form of balance in which the weight of the body under examination is measured by the stretching (torsion) of an elastic wire in the form of a long spiral. A common use of the simple form of spiral balance is in determining the specific gravity of small fragments of minerals, which for this purpose are weighed first in the upper pan and then in that below, which is immersed in water." —Whitney, 1889

Spiral Balance

"A form of balance in which the weight of the body under examination is measured by the stretching (torsion)…