Recording thermometer, unsigned but probably French, with irregular bore in tube and mercury bulbs at each end. Mercury in glass, centigrade. Marked (No 226). Main scale 0 to 26, lower scale 0 to -1.5 Recording thermometer
Negretti and Zambra's patent recording thermometers, 1898. Two mercury in glass thermometers (one wet, one dry bulb) are set in rotating frame, released electrically at predetermined time. Constriction in tube causes mercury column to break on turning upside down. With electric cell. Negretti and Zambra's patent recording thermometers 1898
