Which British inventor developed an early incandescent light bulb in 1878?

Joseph Swan developed an early incandescent light bulb in Britain in 1878. Swan had been experimenting with carbonised paper filaments since 1850, but early versions failed because vacuum pumps were too weak and electricity supplies were unsuitable.

With vacuum-pump expert Charles Stearn, Swan developed an improved process in 1878 that reduced the blackening inside the glass bulb. He demonstrated a lamp using a carbon rod in Newcastle on 18 December 1878; a later demonstration in January 1879 worked successfully for longer. Swan received a British patent for his improved method in 1880.

The familiar mix-up is with Thomas Edison, who developed a commercially practical incandescent lighting system in the United States around the same period. Edison’s work was important, but Swan’s British experiments and demonstrations predated or overlapped his commercial success. The two eventually became involved in a patent dispute and later joined forces in the Edison-Swan United Electric Light Company.

Swan’s lamps helped bring electric lighting into public spaces. In 1881, London’s Savoy Theatre became the first theatre—and the first public building—to be lit entirely by electricity using Swan lamps.