Fig. 1. Thermolimit respirometry diagram. Simplified and not to scale. Gas streams are denoted by thick lines, and their directions by arrowheads. Thin lines are electrical connections. PTC, Peltier-effect temperature control cabinet (controlled area within hatched walls); PELT-4, controller for cabinet, in turn controlled by the adjacent computer; A, ant; AD-1, activity detector with infrared emitter (E) and detector (D); T, thermocouple in chamber, connected to thermocouple meter (TC1000); RC, respirometry chamber; EQ, equilibration coil; CA, CO₂ analyzer; RA, room air; DAD, Drierite/Ascarite/Drierite drying and CO₂ scrubber column; P, pump; MFCV, mass flow control valve; MFC2, mass flow control electronics unit; UI2, 16-bit data acquisition interface attached to the adjacent computer. See text for details.