Psychometer

• The auditor monitors a device known as an electro-psychometer, or E-meter. The pre-Clear holds a metal cylinder in each hand, both of which are attached by wires to the E-meter.
(Radar Online.com)
• But the tool that governs all, for outdoor practices, is the wet-ball psychometer. Its a fancy name for a heat index indicator, Coach James explains. If it reads below 87, the GHSA allows full practices, provided players take four 3-minute breaks per hour.
(Wrcbtv.com)