Original Callendar electrical temperature recorder (including integrator) in wooden case, 1897. Callendar Temperature Recorder, 1897 1897
Clearspan P100L single pen temperature recorder with spare chart and accessories, 1970-78. Calibrated to use copper constantin thermocouple. Single-Pen Electrical Temperature Recorder, 1970-78 1970-1978
Single thread electrical temperature recorder in glazed case, by The Cambridge Scientific Instrument Company Ltd., Cambridge, England, 1910-14. Range say 0-1000°C, with 100 charts Single Thread Temperature Recorder, 1910-14 1910-1914
Photothermograph commissioned by the Meteorological Committee of the Royal Society, some design specifications attributed to Francis Ronalds, made in England, UK, 1867. Installed and operated at Radcliffe Observatory, Oxford. Photothermograph used at Radcliffe Observatory, Oxford 1867