Piezometric methods have been reviewed in detail by Whalley [4], who describes the
piezometer as an instrument that determines the compression of a fluid. The volume
change caused by pressurizing the system can be measured by the displacement of a piston
or the contraction of a bellows cell. The compressed fluid can also be confined by liquid
mercury whose meniscus is observed. The volume change of the primary measurement
must be carefully corrected from the dilation of the container.
Nelson et al. [123] have determined the volume changes for the phase transitions occurring
in n-alkanes of mean chain lengths. The sample was enclosed within a capsule of lead
that was sealed by a cold-solder technique. The capsule was deposited within a metal bellows,
whose remaining volume was filled with a plasticizer. Solid to solid and solid to liquid
first-order phase transitions were detected as discontinuities in the dilation of the bellows.
Figui6re et al. [ 124] used a construction, where the sample was directly filled in the bellows.
Sato et al. [ 125] report the results of their measuredp VT properties of polymers using a metal