This letter was written by Joseph Swan to Rothbury photographer John Worsnop on 9th November 1897, in which he describes the first use of his incandescent lightbulb in a private residence other than his own, at Lord Armstrong’s house, Cragside. He writes, “…the effect was splendid and never to be forgotten”.

Sunderland-born physicist and chemist Sir Joseph Wilson Swan (1828-1914) is world-renowned for his invention of an early electric incandescent lightbulb, which became the very first to light public spaces and private residences. Swan conducted many of the experiments in perfecting this landmark technology at his home in Low Fell, Gateshead. He personally supervised the installation of lightbulbs at Cragside, the Northumberland residence of his friend, industrialist Lord William Armstrong, in December 1880. In this letter, he gives a vivid account of that momentous occasion.

Here is Swan and his pictured in their home at Warlingham, c. 1904