Differential Thermometer

Differential air thermometer. Yellow coloured soft wood frame with vertical scales places on ebonized base. With one bulb in line with a radiant heat source, and the other well clear, the expansion of air is indicated.

42 cm high and 12 cm wide.

In fine condition.

Ca. 1900.

€ 185,-

Antique thermometer 1Antique thermometer 2 Antique thermometer 3