U.S. Supreme Court
Kendall v. Winsor, 62 U.S. 21 How. 322 322 (1858)
Kendall v. Winsor
62 U.S. (21 How.) 322
The ultimate object of the patent laws being to benefit the public by the use of the invention after the temporary monopoly shall have expired, one who conceals his invention and uses it for his own profit is not entitled to favor if another person should find out and use the invention.
But this does not include the case of an inventor who forbears to apply for a patent until he has perfected his invention or tested its value by experiments.
Whether or not an inventor intended to do this or negligently to postpone his claims to a patent -- as for instance, by acquiescing with full knowledge in the use of his invention by others -- are questions which ought properly to be left to the jury.
If a person should surreptitiously obtain knowledge of the invention and use it, he would have no right to continue to use it after the inventor should have obtained a patent.
The facts in the case, the instructions asked for and refused upon the trial in the circuit court, and also those given to the jury by the court, are all set forth in the opinion of the Court. Under these instructions, the jury found a verdict for the plaintiff and assessed his damages in the sum of two thousand dollars. chanroblesvirtualawlibrary