A professional who heats and cools thermometers to test flow of mercury, remove excess mercury, and establish calibration reference points. Responsibilities include:

• Places thermometer alternately into hot water and crushed ice and rubs thermometer across corrugated pad to force excess mercury and mercury vapor from thermometer into temporary top chamber of thermometer.
• Spins thermometer in centrifuge to force remaining mercury back into bulb at bottom of thermometer.
• Observes rise and fall of mercury column and rejects thermometer if particles of mercury or dirt cling to bore, or bore constrictions prevent specified rise and fall of mercury.
• Heats thermometer at two known temperatures and marks height of mercury column on tube as reference points for calibration.