The instructions of the presiding judge seem to have been in entire conformity with the decision of this court in the case of Dickinson v. Hall, 14 Pick. 217. It was there insisted that the jury were not to find the patent void, and the note without consideration, merely because the machine, the patent right for which was sold, when put to actual use, would yield no pecuniary benefit; but the jury were instructed that, if an invention be utterly frivolous or worthless, it is not, within the meaning of the law, “ useful.” Upon a revision of that case by the full court, it was held that an invention, in order to be the subject of a patent right, must be useful for some beneficial purpose, and that the instructions given at the trial were correct. It was there deemed an immaterial circumstance that the vendor supposed t.he patent a valid one, and was wholly innocent of fraud in the matter, the case being put upon the *147bioad ground that the vendor was not the owner of any legal patent right, because the same was wholly void, the invention not being of any beneficial use.
We are aware that somewhat different views have been taken in other tribunals, as to this defence, where the vendor acted bona fide, and honestly supposed that the invention might be made beneficially useful, although in the event it proved otherwise. But we must give effect to our own course of decisions on this subject.
The evidence offered by the defendant was properly admitted, and the case submitted to the jury under proper legal instructions. Exceptions overruled.