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Johnson–Williams liquid water probe - A hot-wire type instrument for measuring the liquid water content of clouds in situ. The probe is most often used on research aircraft, but also occasionally at mountain-top installations and in wind tunnels. Resistivity changes, which occur as cloud droplets in the airflow that impinge on, and evaporate from, an exposed electrically heated wire, are sensed by an electric circuit. The liquid water content of the air is estimated from this signal using compensations for air temperature variations detected by a similar unexposed wire in the probe and knowledge of the airspeed.

Jordan sunshine recorder - A sunshine recorder of the type in which the timescale is supplied by the motion of the sun. It consists of two opaque metal semicylinders mounted with their curved surfaces facing each other. Each of the semicylinders has a short narrow slit in its flat side. Sunlight entering one of the slits falls on light-sensitive paper (blueprint paper) that lines the curved side of the semicylinder. One semicylinder covers morning hours, the other afternoon hours. The sensitivity of the recording paper is variable, and this introduces an uncertainty in the evaluation of the record.