Marconi-Fleming valve radio receiver, c 1908.

Marconi-Fleming valve radio receiver, c 1908.

Hand spectacles with tortoiseshell frame, 1801-1900.

Alexander Graham Bell, Scottish-born American inventor, 1880.

Bell's 'Harmonic' telegraph transmitter and receiver, 1873-1874.

Gower-Bell telephone transmitter, 1881.

Pair of early Bell telephones, 1878.

John Heathcoat, English inventor, mid 19th century.

Watt's single-acting pumping engine, 1788.

Antiseptic machine, 1879.

Antiseptic machine, 1879.

Watt's single acting steam engine, late 18th century.