U.S. Supreme Court
Cantrell v. Wallick, 117 U.S. 689 (1886)
Cantrell v. Wallick
Argued March 30, 1886
Decided April 12, 1886
117 U.S. 689
Two patents may be valid when the second invention is an improvement on the first, and if the second includes the first, neither patentee can lawfully use the invention of the other without his consent; but a stranger, sued for infringing the second patent, cannot defend by setting up the existence of the first patent. chanroblesvirtualawlibrary
Two machines or devices are substantially identical when they perform substantially the same thing in substantially the same way, to obtain the same result, and they differ from each other in the sense of the patent law, when they perform different functions, or in a different way, or produce substantially different results.
Machine Co. v. Murphy, 97 U. S. 12A, affirmed and applied.
The defendant in a suit for the infringement of a patent for an invention, who sets up prior use and want of novelty as a defense, has the burden of proof upon him to establish the facts set up beyond all reasonable doubt, and in this case the defendants have failed to show the alleged prior use even by preponderance of proof.
This was a bill in equity to restrain the infringement of letters patent. The case is stated in the opinion of the court.