The Incandescent Lamp Patent

Brief Fact Summary. The Electric Light Company (Plaintiff) filed suit to recover damages allegedly incurred for infringement of their letters of patent.

Synopsis of Rule of Law. A patent must state specifically the composition of the materials to be combined to produce the intended result and if they are not capable of an exact description, then the inventor is not entitled to a patent.

Facts. The Electric Company (Plaintiff) filed suit against McKeesport (Defendant) to recover damages for the infringement of letters patent issued to the Electro-Dynamic Light Company, assignee of Sawyer and Man, for an electric light. The defendants justified their actions under certain patents issued to Thomas Edison, denied their novelty and utility and claimed that they had been fraudulently and illegally obtained. The circuit court held the patent to be invalid and dismissed. Plaintiff appealed.

Issue. Must a patent state specifically the composition of the materials to be combined to produce the intended result and if they are not capable of an exact description, then is the inventor not entitled to a patent?

Held. (Brown, J.) Yes. A patent must state specifically the composition of the materials to be combined to produce the intended result and if they are not capable of an exact description, then the inventor is not entitled to a patent. The two main defenses to the patent are: (1) that it is defective upon its face in attempting to monopolize use of all fibrous and textile materials for the purpose of electric illumination; and (2) that Sawyer and Man were not actually the first to discover that these materials were better adapted than mineral carbons for such use. With respect to the first defense, if the patentees had discovered in the fibrous and textile substances a quality distinguishing them from other materials adapting them particularly to incandescent conductors, such claim might prevail. Sawyer and Man presumed they discovered in carbonized paper the best material for an incandescent conductor. Rather than confining themselves to this material, they made a broad claim for every fibrous or textile material. Rev. Stat. § 4888 requires the application to include a written description of the device and the manner and process of making and using it in full, clear, and concise terms. The purpose of this requirement is to inform the public of what the patentee claims to hold a patent to. With the specification, however, only gives the names of the substances used without stating the relative proportions, the court must declare the patent void. If Sawyer and Man had discovered that a certain type of carbonized paper sufficed, then their claim to all carbonized paper might not fail. However, the fact that such paper is a fibrous material does not allow them to limit other inventors to the entire domain of such materials. The claims of this patent are too indefinite. Affirmed.

Discussion. Rev. Stat. § 4888 is now found in 35 U.S.C. § 112. That section requires that a patent claim include a written description, clear claim and enablement requirement.