&sect¹;10. Actions for violation² of patent rights.

51. The act of July 4, 1836, section 14, provides, That whenever in any action for damages for making, using, or selling the thing whereof the exclusive right is secured by any patent heretofore granted, or by any patent which may hereafter be granted, a verdict shall be rendered for the plaintiff in such action, it shall be in the power of the court to render judgment³ for any sum above the amount found by such verdict as the actual damages sustained by the plaintiff, not exceeding three times the amount thereof, according to the circumstances of the case, with costs; and such damages may be recovered by action on the case, in any court of competent jurisdiction⁴, to be brought in the name or names of the person or persons interested, whether as patentee, assignees, or as grantees of the exclusive right within and throughout a specified⁵ part of the United States.

52. - Sect. 15. That the defendant⁶ in any such action shall be permitted to plead the general issue, and to give this act, and any special matter in evidence, of which notice in writing may have been given to the plaintiff or his attorney, thiry days before trial, tending to prove that the description and specification⁷ filed by plaintiff does not contain the whole truth relative to his invention or discovery, or that it contains more than is necessary to produce the described effect; which concealment⁸ or addition shall fully⁹ appear to have, been made for the purpose of deceiving the public, or that the patentee was not, the original and first inventor or discoverer of the thing patented, or of a substantial and miaterial art thereof claimed as new, or that it had teen described in some public work anterior¹⁰ to the supposed discovery thereof by the patentee, or had been in public use, or on sale with the consent and allowance of the patentee before his application for a patent, or that, he had surreptitiously or unjustly obtained the patent for that which was in fact invented or discovered by another, who was using reasonable diligence in adapting and perfecting the same; or, that the patentee if an alien at the time the patent was grauted, had failed and neglected for the space of eighteen months from the date of the patent, to put and continue on sale to the public, on reasonable terms, the invention or discovery for which the patent issued; in either of which cases judgment shall be rendered for the defendant, with costs. And whenever the defendant relies in his defence on the fact of a previous invention, knowledge, or use of the thing patented, be shall state, in his notice of special matter, the names and places of residence of those whom he intends to prove to have possessed¹¹ a prior knowledge of the thing and where the same had been used: Provided, however, that whenever it shall satisfactorily appear that the patentee, at the time of making his application for the patent, believed himself to be the first inventor or discoverer of the thing patented the same shall not be held to be void on account of the invention or discovery or any part thereof having been before known or used in any foreign country, it not appearing that the same or any substantial part thereof, had before been patented or described in any printed publication. And provided, also, that whenever the plaintiff shall fail to sustain his action on the ground that in his specification of claim is embraced more than that of which he was the first inventor, if it shall appear that the defendant had used or violated any part of the invention justly and truly specified and claimed as new, it shall be in the power of the court to adjudge and award as to costs as may appear to be just and equitable¹².