U.S. Supreme Court
Keyes v. Grant, 118 U.S. 25 (1886)
Keyes v. Grant
Argued April 2, 1886
Decided April 19, 1886
118 U.S. 25
When the defendant in a suit for the infringement of a patent sets up a prior publication of a machine anticipating the patented invention, and it appears that there are obvious differences between the two machines in the arrangement of the separate parts, in the relation of the parts to each other, and in their connection with each other in performing the functions for which the machine is intended, and experts differ upon the questions whether these differences are material to the result, and whether they required the faculty of invention, those questions are questions of fact to be left to the determination of the jury, under proper instructions from the court.
This was a suit at law to recover damages for the infringement of letters patent. The case is stated in the opinion of the Court. chanroblesvirtualawlibrary