Stethoscope, 20th century.

Stethoscope, 20th century.

Ring Nebula in the constellation of Lyra (M57), 14 July 1887.

'The Thames Below London Bridge', c 1900.

Space Shuttle Discovery lifting off, Florida, July 2005.

Steel betel nut cutter, Indian, 19th century.

Glas prism, used by Sir William Herschel, c 1770-1822.

Nut cutter with handles, 19th century.

'Meet the Cutters - they live in a disused

Lee de Forest, American electrical engineer and inventor, 1961.

Baird television receiver, 1936.

Woman examining Mullard valves, Radiolympia, Olympia, London, 1934.