International
Tables for
Crystallography
Volume C
Mathematical, physical and chemical tables
Edited by E. Prince

International Tables for Crystallography (2006). Vol. C, ch. 3.2, p. 158

Section 3.2.2.4. Method of Archimedes

F. M. Richardsa

3.2.2.4. Method of Archimedes

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The specimen is weighed in air and again in a liquid of accurately known density. From the apparent loss of weight the volume is computed, and thence the density (Reilly & Rae, 1954[link]). The technique requires little special equipment and is capable of great accuracy when used with large, well formed crystals. The accuracy is maximized by using immersion liquids of density as close to that of the crystals as possible. For precise work, correction must be made for the interfacial tension between the supporting wire and the upper surface of the suspending medium.

A torsion microbalance has been adapted to the determination of crystals as small as 25 mg (Berman, 1939[link]). A probable accuracy of better than 1% may be achieved with this micro-method.

A densitometer based on Archimedes principle with control of the composition of the gas phase and a wide temperature range has been described by Graubner (1986[link]). The method is not suitable for finely divided materials.

References

Berman, H. (1939). A torsion microbalance for the determination of specific gravities of minerals. Am. Mineral. 24, 434–440.
Graubner, H. (1986). Densitometer for absolute measurements of the temperature dependence of density, partial volumes and thermal expansivity of solids and liquids. Rev. Sci. Instrum. 57, 2817–2826.
Reilly, J. & Rae, W. N. (1954). Physico-chemical methods, Vol. 1, 5th ed., pp. 577–608. New York: van Nostrand.








































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