Callendar's compensated air thermometer

Callendar's compensated air thermometer

[¦kal·ən·dərz ¦käm·pən‚sād·əd ′er thər‚mäm·əd·ər] (engineering) A type of constant-pressure gas thermometer in which errors resulting from temperature differences between the thermometer bulb and the connecting tubes and manometer used to maintain constant pressure are eliminated by the configuration of the connecting tubes.