Consolidated Electric Light Co. v. McKeesport Light Co. (The Incandescent Lamp Patent Case)
United States Supreme Court
159 U.S. 465 (1895)
Sawyer and Man obtained a patent for an electric
incandescent light, which was a lighting system involving the passage of an
electric current through a suitable conductor. Claims 1 and 2 of the patent described
an incandescing conductor composed of “carbonized fibrous or textile material,”
and Claim 3 provided that Sawyer and Man used carbonized paper as the conductor.
Consolidated Electric Light Company (Consolidated) (plaintiff) filed a bill in
equity against McKeesport Light Company (McKeesport) (defendant), seeking
damages for patent infringement based on a lighting system developed by Edison
Electric Light Company (Edison). Edison’s commercial incandescent light was
designed similarly to Sawyer and Man’s, but used a conductor formed from
carbonized bamboo. Edison had tested numerous categories of vegetable growth for
several months before he discovered that bamboo’s parallel fibers made it a
particularly good conductor. Consolidated argued that Edison’s bamboo conductor
infringed the Sawyer and Man patent because bamboo was a “fibrous or textile
material” covered by the patent. The circuit court considered the argument that
the patent was invalid on its face because Sawyer and Man improperly attempted
to claim a monopoly on all fibrous and textile materials for the purpose of
electric lighting. The court held the patent invalid, and Consolidated
Rule of Law
Holding and Reasoning (Brown, J.)
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