Sketch of carbon atoms, 1990s.

Swan's electric filament lamp, 1878-1879.

Experimental upper set of false teeth, late 20th century.

Experimental upper set of false teeth, late 20th century.

David Edward Hughes, English electrician and inventor, c 1880s.

David Edward Hughes, English electrician and inventor, c 1880s.

David Edward Hughes, English electrician and inventor, c 1880s.

George Foster, President of the Physical Society, 1880-1910.

Cowper's original writing telegraph, 1878.

Silvanus P Thompson's 'valve' telephone, 1882-85.

Electric filament lamps made by Swan (left) and Edison (right), 1878-1879.

David Edward Hughes, English electrician and inventor, c 1880s.