Mr. Justice Bewer,
after stating the case, delivered the opinion of the court.
The case presented by the foregoing facts is one not free from difficulties. The government has used .the invention of Mr. Clark and has profited by such use. It was an invention of value. The claimant and appellant is the owner of such patent, and has never consented to its use by the gbvernment. From these facts, standing alone, an obligation on the part of the government to pay naturally arises. The government has no more_ po_wer to appropriate a man's property invested in a patent than it has to take his property invested in real esíaté ; nor does the mere fact that an inventor is at the time of his invention' in the employ of the government transfer to it any title to, or interest in it. An employé, performing all the duties assigned to him in his department of service, may exercise his inventive faculties in any direction he chooses, with tl^e assurance that whatever invention he may thus conceive and perfect is his individual property. There is no difference between the government and any other employer in this respect. But this general rule is subject to these limitations. If one is employed to devise' or perfect an instrument, or a paeans for accomplishing a prescribed result, he cannot, after Successfully accomplishing the work for which he was employed, plead title thereto as aga.inst his employer. That which he has been employed and paid to accomplish becomes, when accomplished, the property of his employer. Whatever rights as an individual he may have had in and to his inventive powers, and that which they are able to accomplish, he has sold in advance to his employer. So, also, when one is in the employ of another in a certain line of work, and devises an improved method or instrument for doing that work, and uses the property of his employer and the services of other employes to develop and put in practicable form his invention, and explicitly assents to the use by his employer of such invention, a jury, or á court trying the facts, is warranted in finding that he has so far recognized the obligations of service flowing from his employment and the benefits resulting from his use of the property, and the assistance of the coemployes, of his employer, as to have given to such employer an irrevocable license to use such invention. The case of M'Clurg v. Kingsland, 1 How. 202, is in point. In that> case was presented the question as to the right of defendants to use an invention made and patented by one Harley., The facts as stated and the rulings of the court are these: "That Harley was employed by the defendants at their foundry in Pittsburgh, receiving wages from them by the week; while so,employed, he claimed to have invented the improvement patented, and, after several unsuccessful experiments, made a successful one in October, 1834; the experiments were made in the defendants' foundry, and wholly at their expense, while Harley was receiving his wages, which were increased on aocount of the useful result. Harley continued in their employment on wages until January or February, 1835, during all which time he made rollers for them; he often spoke about procuring a patent, and prepared more than one set of papers for the purpose ; made his application the 17th February, 1835, for a patent; it was granted on the 3d of March, assigned to the plaintiffs on the 16th of March, pursuant to an agreement made in January. While Harley continued in the defendants' employment, he proposed that they should take out a patent, and purchase his right, which they declined; he made no demand on them for any compensation for using his improvement, nor gave them any notice not to use it, till, on some misunderstanding on another subject, he gave them such notice, about the time of his leaving their foundry, and after making the agreement with the plaintiffs, who owned a foundry in Pittsburgh, for an assignment to them of his right. The defendants continuing to make rollers on Harley's plan, the present action was brought in October, 1835, without any previous notice by them. The court left it to the jury to decide what the facts of the case were; but, if they were as testified, charged that they would fully justify the presumption of license, a special privilege, or grant to the defendants to use'the invention; and the facts amounted to 'a consent and allowance of such use,' and show such a consideration as would support an express license or grant, or call for the presumption of one to'meet the justice of the cáse, by exempting them from liability; having equal effect with a license, and giving the defendants a right to the continued use of the invention.'? On review in this court, the rulings of the trial court were sustained. That case is decisive of this. Clark was in the employ of the government when he made this invention. His experiments were wholly at the expense of the government. He was consulted as to the proper stamp to be used, and it was adopted on his recommendation. He notified the government that he would make no charge if it adopted his recommendation and used his stamp; and for the express reason that he was in the government employ, and had used the government •machinery in perfecting his stamp. He never pretended, personally, to make any charge against the government. Indeed, there is but one difference between that case and this: in that, Harley's wages were increased on account of his invention; in this, Clark's were not; but such difference does not seem vital. We think, therefore, the rulings of the Court of Claims were correct, and its judgment is
Affirmed.