As to recovering back an amount paid; Hare took out a patent for an apparatus for preserving the essential oil of hops in brewing, and afterwards granted to Taylor the privilege of using the invention for the residue of the term of the patent; and in consideration thereof, Taylor covenanted to pay to Hare, during the term, an annuity of £100. There was no fraud on the part of Hare, who, it seems, supposed the patent to be valid. After Taylor had used the apparatus, and paid the annuity for several years, it was discovered that Hare was not the inventor, but the patent had never been repealed. Taylor then brought an action against Hare to recover back the money. Sir J. Mansfield C. J. "It is not pretended that any action like the present has ever been known. In this case, two persons equally innocent make a bargain about the use of a patent, the defendant supposing himself to be in possession of a valuable patent right, and the plaintiff supposing the same thing. Under these circumstances, the latter agrees to pay the former for the use of the invention, and he has the use of it; non constat what advantage he made of it; for any thing that appears, he may have made considerable profit. These persons may be considered, in some measure, as partners in the benefit of this invention. In consideration of a certain sum of money, the defendant permits the plaintiff to make use of this invention, which he would never have thought of using had not the privilege

been transferred to him. How then can we say that the plaintiff ought to recover back all that he has paid? I think that there must be judgment for the defendant." Heath J. Heath J. "It might as well be said, that if a man lease land, and the lessee pay rent, and afterwards be evicted, that he shall recover back the rent, though he has taken the fruits of the land.” Chambre J. "In the case of Arkwright's patent, which was not overturned till very near the period at which it would have expired, very large sums of money had been paid; and though something, certainly, was paid for the use of the machines, yet the main part was paid for the privilege of using the patent right, but no money ever was recovered back which had been paid for the use of that patent." Judgment of nonsuit."

In the above case some stress was laid on the circumstance that the patentee held a patent that was apparently good on the record. In a preceding action to recover the price agreed to be paid for the use of a patent that was void on the record, the decision was against the plaintiff. It was a decision of Lord Kenyon, C. J. and Ashhurst, Buller and Grose, Justices, in an action of covenant on articles of agreement. It appeared that the plaintiffs, who were assignees of a patent for a machine to be fixed to a

11 Taylor v. Hare, 4 B. & P. 260.

common stocking-frame, for making a sort of net or open work, called point net, had agreed that the defendant might use one stocking-frame with their patent affixed thereto, in case the same should be worked only in the manner described in the specification; and that the defendant had covenanted not. to use any of the patent machines, or any machines resembling the same, except the stocking-frame and machine so allowed to be used by him. The action was brought for a breach of this covenant. The defendant pleaded in bar that the specification was not enrolled in time, that the invention was not a new invention, and that the original patentee was not the inventor. The plaintiffs demurred, and contended that he was estopped by his deed from putting those matters in issue. Lord Kenyon. "It is said that the defendant is estopped in point of law from saying that the plaintiffs had no privilege to confer; but the doctrine of estoppel is not applicable here. The person supposed to be estopped is the very person who has been cheated and imposed upon. This does not resemble the case of landlord and tenant; for the tenant is not, at all events, estopped to deny the landlord's title; the estoppel only exists during the continuance of his occupation; and if he be ousted by a title paramount, he may plead it." Buller J. "If the plaintiffs had the exclusive right to the machine, they might convey it to any other person. It is now discovered that they had no such right; and there

fore the defendant has not the consideration for which he entered into his covenant; and notwithstanding which they say he is still bound." Judgment for the defendant.12

The distinctions between these two cases are, that in one, the agreed price for the use of the machine was sought to be recovered; in the other, the agreed price having been paid, was sought to be recovered back; and in the first case the record showed a prima facie good title in the party agreeing to let the use of the machine; in the latter, it did not show such a title. In both cases the party professing to be the proprietor of the patent, thought himself entitled to it; there appears, therefore, not to have been any intentional fraud in either contract.

The question of fraud, and the fact of possession being out of the case, it is obvious that various other considerations might have an influence in determining the decision between parties to a sale of this description. The payment may have been under a judgment, as in some instances, under Oliver Evans's patent for the hopperboy, which was eventually adjudged to be bad; or a settlement may have been made between the parties with a full, or at least an equal knowledge, of the facts. In general, after payment, the presumptions seem to be in favor of the party to whom the payment is made.

A patent right, like property of every other description, is liable to be assigned, not only by the agreement of the proprietor, but also by the operation of law independently of any voluntary act of the proprietor for this particular purpose. An instance of this has already been mentioned in the transfer of the right to the executors or administrators, or to the legatee of the proprietor in case of his decease, in the same manner as any other personal property.

In virtue of a general assignment under a bankrupt or insolvent law, of all the property of a proprietor of a patent right, or a share in one, his interest will be transferred with his other property to the assignees for the benefit of his creditors. Of the application of this doctrine to the interest held under a patent issued before such general assignment is made, there is no doubt, and it is unnecessary to cite cases, or to go into any discussions on this point.

The only question in relation to this subject that needs to be considered, is, whether any interest is transferred under such an assignment in an invention for which a patent has not been granted at the time of the assignment being made. It is held under the English bankrupt law that where a bankrupt, after the act of bankruptcy, and after the assignment of his effects by the commissioners of bankruptcy, but before his final discharge, takes out a patent, his