Piston and cylinder compress/expand air measuring temp. and pressure.

Piston and cylinder compress/expand air measuring temperature and pressure. Pushing down on the plunger handle forces the close-fitting piston into the cylinder, causing a pressure and temperature rise in the cylinder air. The compound gauge indicates the air pressure in lbs./sq.ft. The rise in temperature heats a thermocouple in the base of the cylinder. The signal from the thermocouple is magnified by the D.C. amplifier and shown on the screen using the projection galvanometer. Pulling up on the plunger handle causes a temperature decrease... TEMPERATURE AND EXPANSION.