Standard Kilogramme, c 1930s.

Group of standard weights from around the world.

Bowstring Girder Bridge, Binghamton, New York, United States, c 1870.

Forging files, Cyclops Steel and Iron Works, Sheffield, Yorkshire, 1914-1918.

Standard kilogramme.

Bronze 'duck' weight, Babylonian, 8th century BC.

Bronze 'ram' weight, Babylonian, 8th century BC.

Pasanger locomotive, 1837. Model (scale 1:

Pasanger locomotive, 1837. Model (scale 1:

Tsar Alexander inspects the 'infants' school' at Woolwich, 1874.

'The Britannia Tubular Bridge', Menai Straits, Wales, c 1860.

'The East End', 1851.