Lexplug logoLexplug

Consolidated Electric Light Co. v. McKeesport Light Co.

Supreme Court of the United States
159 U.S. 465 (1895)
ELI5:

Rule of Law:

A patent claim for a class of materials is invalid if it is overly broad and fails to describe the invention with sufficient specificity to enable a person skilled in the art to replicate it without undue experimentation.


Facts:

  • For many years, various inventors attempted to develop a commercially viable incandescent light bulb.
  • A primary challenge was finding a durable material for the filament that would glow when electrified without quickly disintegrating.
  • William Sawyer and Albon Man experimented with carbonized materials and discovered that carbonized paper and wood could function as incandescent conductors.
  • Based on these experiments, Sawyer and Man obtained a patent that included a broad claim for the use of any "incandescing conductor made of carbonized fibrous or textile material."
  • Separately, Thomas Edison conducted extensive research, testing over 6,000 different vegetable growths to find an optimal filament material.
  • Edison discovered that a specific type of bamboo, due to its unique parallel fiber structure, was far superior to other materials, including the paper and wood carbons used by Sawyer and Man.
  • Edison's success with bamboo was due to its specific structural properties, not a general quality common to all fibrous materials, most of which proved unsuitable.
  • The owner of the Sawyer and Man patent sued the manufacturer of Edison's lamp, alleging that using a carbonized bamboo filament infringed their patent on all "fibrous or textile material."

Procedural Posture:

  • The holder of the Sawyer and Man patent filed a suit for patent infringement in a United States Circuit Court against the manufacturer of the Edison lamp.
  • The Circuit Court (the trial court) found in favor of the defendant, issuing a decree against the complainant.
  • The complainant (appellant) appealed the Circuit Court's decision to the United States Supreme Court.

Locked

Premium Content

Subscribe to Lexplug to view the complete brief

You're viewing a preview with Rule of Law, Facts, and Procedural Posture

Issue:

Is a patent claim valid if it seeks to monopolize an entire class of materials for a specific use when the patentee has only discovered the utility of a few specific materials within that class and has not identified a general quality that makes the entire class uniquely suitable for that purpose?


Opinions:

Majority - Mr. Justice Brown

No. The patent claim is invalid because it is too broad and fails to meet the statutory requirement for a specific and enabling description. A patentee who discovers that one type of material from a broad class works for a particular purpose cannot lay claim to the entire class of materials, thereby foreclosing further and more successful invention by others. The patent statute requires a description so clear and exact that a person skilled in the art can make and use the invention without extensive independent experimentation. Sawyer and Man's claim over all fibrous and textile materials fails this standard, as there is no generic quality that makes the entire class suitable, and discovering a truly effective material like bamboo required Edison's exhaustive independent research. To uphold such a broad claim would discourage, rather than promote, invention by allowing the imperfect discovery of one inventor to put "under tribute the results of the brilliant discoveries made by others."



Analysis:

This decision reinforces the enablement and definiteness doctrines of patent law, which prevent inventors from claiming more than they have actually invented and described. It establishes the precedent that a patent's claims must be commensurate with its disclosure, meaning a patentee cannot claim a broad genus of materials based on the discovery of only a few species, especially when no common, unifying principle makes the entire genus suitable for the claimed purpose. This ruling protects subsequent innovators who, through diligent research, discover a superior species within that genus. It ensures that broad fields of scientific inquiry remain open for exploration rather than being monopolized by an early, incomplete discovery.

🤖 Gunnerbot:
Query Consolidated Electric Light Co. v. McKeesport Light Co. (1895) directly. You can ask questions about any aspect of the case. If it's in the case, Gunnerbot will know.
Locked
Subscribe to Lexplug to chat with the Gunnerbot about this case.

Unlock the full brief for Consolidated Electric Light Co. v. McKeesport Light Co.