THE GREEN BAG patent, and from its expiration the free enjoyment of any benefits which may flow from it forever thereafter." It was thus, in this twofold way, of the commercial benefit to the public; (a) by use of the invention, under tribute to the patentee, during the limited term of the patent; and (6) by free enjoyment of the invention disclosed by the patent after its limited term, that the purpose of clause 8 of sec. 8 of Article i of the Constitution of the United States was intended to be carried into effect, by just patent laws to be passed by Congress and by equitable interpreta tion of such laws by the courts. For that purpose is thus expressed in that part of the Constitution of the United States just referred to : "That Congress shall have power" . . . "to promote the progress of science and useful arts, by securing, for limited terms, to" . . . "inventors, the exclusive right to their" . . . "discoveries." It was progress, action, reward for pres ent use, for a limited time, to the inventor who made, disclosed, and used his invention, that those who framed this part of our Con stitution had in mind, as is clear from the language used, from the history of the times, and from the interpretation of the law enacted in pursuance of that provision, as that law has been interpreted by such learned judges as Judge Shipman, and by such a truly learned, scholarly, lawyer-like and philosophical text writer on patent law in the United States as Mr. Robinson. In England the best text writers on patent law have all shown that it is essen tial to and inherent in the history and policy of the law that the owner of a patent for an invention shall have brought his invention into commercial use, so that he is injured in his business of making, using, or selling his invention by the infringer, before a court of equity will heed his complaint. Mr. Cunynghame, in his work on patents, published in England in 1894, expresses this very thought, in his discussion of the
history and policy of the patent laws of England; at pages 20 to 25 of his work he says: "It is to be observed that the publication of the invention by the patentee was not originally insisted on, nor was it any part of the terms or conditions upon which the grant of letters patent was founded. The object of the framers of the Statute of Monopolies seems rather to have been the introduction of new mysteries or manufac tures into England than the publication of the methods of working them, for no pro vision of publication is contained in that statute." . . . Then, speaking of the consideration for the grant, Mr. Cunynghame states: "The true consideration upon which it was founded was the creation or planting on English soil, of some trade which was previously not in use within the realm, and the greatest publicity expected was that which would arise from the training of a number of apprentices and artificers in the practice of it." Also at pages 316 and 317 of this same work, Mr. Cunynghame states: "In order to constitute an infringement, the act complained of must be one calcu lated to injure the trade profits of the patentee. Having regard to the words, 'the whole profit and advantage of the invention,' and remembering that the object of patent law is not to reward scientific discovery, but to encourage trade, it follows that in general only those acts will be treated as infringements which are field either directly or indirectly to injure the trade of a patentee. "And, therefore, merely to use a patented invention for experiment will not be an infringement. And, perhaps, even to use a patent in a private way for self-instruction, not for profit or for business purposes, would not be an infringement, though that is more doubtful. But to make, use, or sell an object made according to the invention for the purposes of profit will be an infringe ment, and to buy an article made according
