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
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
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