An early incandescent light bulb made by Sir Joseph Wilson Swan in the 1870s that sold for £7500 at Bonhams.
Sunderland-born Swan created his prototype incandescent light bulb around 1860, later using carbonised thread and improved vacuum pumps to increase its quality and lifespan.
He first publicly demonstrated this longer-lasting product during a 1878-79 lecture series at the Newcastle upon Tyne Chemical Society before forming the Swan Electric Light Company Ltd in 1880. Bonhams’ rare survivor, with a carbon rod filament, dates from c.1877.
Measuring 5in (13cm) across and mounted horizontally in a mahogany case, a brass plaque reads: The First Incandescent Electric Lamp. This was made in 1877 (circa) by Sir (then Mr) Joseph Wilson Swan.
Previously exhibited at The Royal Society, it had been estimated at £4000-6000 at the auction on September 19.
