• a glass cylinder of very thick glass containing the piezometric liquid (usually water), which allows the liquid, the compressibility of which is to be studied, to be subjected to different pressures;
• the actual piezometer, the heart of the instrument immersed in the piezometric liquid, which allows measurement of miscellaneousations in volume of the liquid under consideration, the pressures generating them and the temperatures at which they occur.

In the one presented here, the piezometric liquid is water, the glass cylinder containing it (height 38 cm, outside diameter 7.6 cm) is attached with putty to a heavy circular brass base above which is a sleeve of brass enveloping the cylinder almost to half its height (16.2 cm). It is closed at the top by a brass lid and is enveloped by a brass band 6.8 cm wide. ...continues