This Day in Tech History

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Light Wars


July 11, 1892: U.S.Patent Office Says J.W. Swan Invented Electric Light Carbon

In July of 1892 the U.S. Patent Office says J. W. Swan, rather than Thomas Edison, invented the electric light carbon for the incandescent lamp.

So, who invented the light bulb?

Most people would answer Edison, but they would be wrong. In fact, they were being used as electric lights for more than 50 years prior to his patent date.


An inventor named Joseph Swan demonstrated the same carbon filament light bulb in Newcastle at least ten months prior to Edison’s announcement.  In addition, Swan received a British patent in 1878 for the same bulb that Edison patented in the U. S. in 1879.



So did Edison know about Swan’s work, or did they simply work independently and arrive at the same conclusion?

Swan first demonstrated the light bulb at a lecture in Newcastle upon Tyne Chemical Society on 18 December 1878, but he did not receive a patent until 27 November 1880 (patent No. 4933) after improvement to the original lamp. His house (in Gateshead, England) was the first in the world lit by a light bulb, and the world’s first electric-light illumination in a public building was for a lecture Swan gave in 1880.  In 1881, the Savoy Theatre in the City of Westminster, London was lit by Swan incandescent light bulbs, the first theatre and the first public building in the world to be lit entirely by electricity.

Savoy Theatre

Savoy Theatre

How do two inventors, from two different countries invent exact same thing?  Very easily, if one follows in the others footsteps. Swan’s initial findings from tinkering with carbon filament electric lighting, and his preliminary designs, appeared in an article published by Scientific American. Without a doubt, Edison had access to, and eagerly read this article. Giving Mr. Edison the benefit of the doubt, and stopping short of calling him a plagiarist, we can say that he invented the light bulb by making vast improvements to Swan’s published, yet unperfected designs.

Joseph Swan’s 1878 invention (left) and Thomas Edison’s light bulb of 1879

Joseph Swan’s 1878 invention (left) and Thomas Edison’s light bulb of 1879

Eventually, Edison was the one making the big bucks off this invention and Swan was rightfully upset with this situation.

So, if you were in Swan’s boots, what would you do?  Sue the pants off of Edison?  That is exactly what Swan did.

Edison lost in the British courts for infringement of Swan’s patent.  As part of the settlement, Edison was forced to take Swan in as a partner in his British electric works.  The company was called the Edison and Swan United Electric Company. Eventually, Edison acquired all of Swan’s interest in the company.

In the United States, Edison didn’t have the chance to put up a fight.  The U.S. Patent Office had ruled that Edison’s patents were based on the prior art of a man named William Sawyer and were invalid.  In addition, Swan had already sold his U.S. patent rights to the Brush Electric Company in June of 1882.

So why does Edison get all the credit for the invention of the light bulb?  Very simple, he owned the power company – what was to eventually become General Electric.

After all, what use is a light bulb without electricity?


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