Patent-proving Edison lightbulbs to go under hammer

A box of 23 lightbulbs used by Thomas Edison to defend his patent is expected to fetch up to $600,000 US at auction later this month.

The lightbulbs, which were used in an 1890 trial between Edison Electric Light Company and the United States Electric Light Company, were found in 2004 in the attic of a U.S. house.

The controversial trial focused on the construction of the incandescent light bulb — not on its invention, as many inventors developed the same idea at the same time. Edison was able to demonstrate that his design was the only one to function properly and was handed a legal victory on July 8, 1890.

The lightbulbs will be sold on Dec. 13 at the Landmarks of Science auction along with Albert Einstein's first scientific essay and a first edition of Charles Darwin's On the Origins of Species.