![img_11-4.jpg](https://gazette-eu-west2.azureedge.net/media/33572/img_11-4.jpg?width=750&height=500&mode=max&updated=09%2f24%2f2018+12%3a42%3a47)
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.