The O-ring and light bulbs

Edison’s 1882 light bulb patent application shows a rubber seal where the metal and glass of the light bulb are in contact

On reading the letter in the February 2012 issue of Professional Engineering by A. Collins, which has to do with the invention of the light bulb, I am minded to contribute the following to the discussion. 

The O-ring was invented by Niels Christensen and a patent was granted in 1939. It is a point of some irony that Edison’s 1882 light bulb patent application shows a rubber seal where the metal and glass of the light bulb are in contact. This was arguably an unintentional anticipation of Christensen’s invention.

John.C. Jones, University of Aberdeen

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