Six's self-registering thermometer by Cary, 18th century.

Six's self-registering thermometer, 18th century.

Clinical thermometers, 1870-1901.

Clinical thermometers, 1870-1901.

Dr Aitken's clinical thermometer, 1867-1885.

Corn weighing machine, 19th century.

Mercury-in-glas thermometer, French, c 1790.

Mercury-in-glas thermometer, 18th century.

Minimum thermometer,1861-1870.

Minimum thermometer,1861-1870.

Studying x-rays at Charterhouse Rheumatism Clinic in London, March 1955.

Mechanical cash register, c 1910.