
Frost point hygrometer
1951
Frost point hygrometer, made by Casella, London, with balanced bridge thermometer indicators, marked 89/91, BBTI MkIIB, marked 828/54, Met ref 1525

Frost point hygrometer
1951
Frost point hygrometer, made by Casella, London, with balanced bridge thermometer indicators, marked 97/51, BBTI MkIC, marked 302/46, Met ref 2828. Calibrated 31/5/54 Hygrometer II marked Met ref 1104, Mark IIB

First prototype wind direction head for automatic weather station
1963
First prototype wind direction head for automatic weather station, 1963. 6 vane windmill offset on counterbalanced rotating head, with rectangular arm, heavy base

Prototype Meteorological Office frost point hygrometer
Prototype Meteorological Office frost point hygrometer, unsulated chamber