For £300,000, Edison's bulbs shine light on bright idea

They are a collection of old light bulbs in a unprepossessing wooden box. But without them, Thomas Alva Edison might never have claimed his proper place in the history books.

The 23 bulbs were the crucial evidence that clinched victory for the inventor in 1890 after a long-running dispute with a company that was trying to rip off his important breakthrough.

Long considered lost, they have been recently rediscovered in an American attic. And they are now expected to make up to £300,000 at Christie's Landmarks of Science auction in London on Wednesday.

Laurence Fisher, the technical apparatus expert who could not believe his eyes when details of the find arrived in his inbox, said: "It's extraordinary. For many years, if you picked up a textbook on the history of the incandescent bulb, the trial is mentioned but it would say the evidence that was produced was lost.

"The fact that it's remained together in almost perfect condition is staggering. It should not have survived. Most of the bulbs would still work because the filaments are intact - not that anyone should try." Edison obtained his American patent 223,898 on 27 January 1880. A number of incandescent devices pre-date that, including that of Sir Joseph Swan, who received a British patent in 1878. Swan and Edison went on to market their respective devices on either side of the Atlantic.

But the United States Electric Light Company began marketing its own devices as if they were Edison's, using his patent number on the side. That prompted the challenge from the Edison Electric Light Company amid fears the other company's actions were making patents valueless.

To uphold a patent, it is necessary for a person "schooled in the art" to make a working example of the invention according to its description.

But the United States Electric Light Company suggested it was impossible to make Edison's lights in the manner he had specified, thereby "justifying" their own version. As the inventor was on the point of losing, John W Howell, his assistant, was sworn in to give testimony on 8 July 1890.

Pointing towards the box that will be sold on Wednesday, Mr Howell said, triumphantly: "I hereby produce the lamps." Edison's patent was upheld and, following the trial, Edison's holdings became part of the newly-formed General Electric.

Mr Fisher said that if the United States Electric Light Company had won, the detailed specifics of any patent would have been worthless. "Edison was protecting his light bulb and his reputation," he said.

The public can view the box and bulbs at Christie's before the sale from Sunday noon onwards.

Other items in the auction include Albert Einstein's first scientific essay, written when he was 16 and expected to fetch up to £500,000, and a first edition copy of Charles Darwin's On the Origin of the Species by Means of Natural Selection, in its original cloth cover, which has an estimate of £30,000 to £50,000.