Bull v. Pratt

Swift, Ch. J. The ground of the plaintiffs' action is, that the defendant sold to them a patent-right, when a previous patent had been given, which secured the same thing. It was not necessary that they should prove, by evidence from the office of the secretary of state, that letters patent had issued to the defendant, or the person from whom he derived his claim. It was sufficient to shew, that a previous patent had been issued to Tryon, securing the privilege of using the same machine which the defendant used, and which he had sold to the plaintiffs, whereby it was void. To shew this, the evidence offered was pertinent, and was properly admitted. The defendant, to shew that he had purchased the patent-right from Tryon, offered a certain writing in evidence. This writing contained nothing but a licence to the defendant to use his machine without liability to Tryon for violating his patent-right. The licence was personal, and did not convey to the defendant the power of transferring the right of Tryon ; nor did it contain any engagement that he would not sue the grantee of the defendant for using his machine. The writing, therefore, was irrelevant, and properly rejected. The defendant further contended, that here was a sale in writing of the patent-right, with a covenant ; and that the plaintiffs can maintain no action but on the written contract. There was no express covenant in the written contract. The gravamen of the plaintiffs’ action is, that the defendant falsely represented to them, that he had a valid patent-right, [347] by which they were induced to purchase it, when the defendant knew that he had no such patent-right. This is a fraud for which action will lie. In this opinion the other Judges concurred. New trial not to be granted.