compression - machine

from The Century Dictionary.

• noun An air-compressor; a machine for compressing any substance.
• noun A testing-machine for finding the compressive strength of materials.
• noun A machine for determining the physical constants of gases, as vapor pressure, critical temperature, etc. It consists of a wrought-iron barrel to hold mercury, into which compression-tubes for gases, and manometers are inserted at a, a′ , and a″.