profits recoverable in equity by a patentee was surrounded with many difficulties, which the courts had not yet succeeded in overcoming, said:

"But one thing may be affirmed with reasonable confidence, that, if an infringer of a patent has realized no profit from the use of the invention, he cannot be called upon to respond for profits; the patentee in such case is left to his remedy for damages. It is also clear that a patentee is entitled to recover the profits that have been actually realized from the use of his invention, although from other causes the general business of the defendant, in which the invention is employed, may not have resulted in profits, as when it is shown that the use of his invention produced a definite saving in the process of a manufacture. Mowry v. Whitney, 14 Wall., 434; Cawood Patent, 94 U. S. 695. On the contrary, though the defendant's general business be ever so profitable, if the use of the invention has not contributed to the profits, none can be recovered. The same result would seem to follow where it is impossible to show the profitable effect of using the invention upon the business results of the party infringing. It may be added, that, where no profits are shown to have accrued, a court of equity cannot give a decree for profits by way of damages, or as a punishment for the infringement. Livingston v. Woodworth, 15 How. 559. But when the entire profit of a business or undertaking results from the use of the invention, the patentee will be entitled to recover the entire profits, if he elects that remedy. And in such a case, the defendant will not be allowed to diminish the show of profits by putting in unconscionable claims for personal services or other inequitable deductions. Rubber Company v. Goodyear, 9 Wall. 788." And these general propositions, he added, will hardly admit of dispute.

Accordingly, in that case, the bill was dismissed as to the city of Elizabeth, which had infringed, because it appeared that it had made no profit from the use of the patented improvement, while a decree was rendered against the contractor, who had laid the pavement which was the subject of the patent, because he was shown to have made profits from the infringement. The municipal corporation, of course, remained liable to respond in damages in an action at law for any loss which the plaintiff could have established by proof.

The cases of Marsh v. Seymour, supra, arose under the act of 1870, and were bills for injunction and account. Decrees were rendered in favor of the complainant, and a reference ordered to a master to state an account of profits. In both cases, the respondents showing that they had made no profits by reason of the use of the invention, the complainant waived his claim for a recovery on that account, and decrees were rendered for damages on the basis of a license fee for the infringing machines which had been sold,

and nominal damages for those manufactured but not sold. These decrees were affirmed, the court saying, Mr. Justice Clifford delivering its opinion, that "damages of a compensatory character may be allowed to a complainant in an equity suit, where it appears that the business of the infringer was so improvidently conducted that it did not yield any substantial profits, as in the case before the court."

In Parks v. Booth (102 U. S. 96), which was a suit in equity for an injunction, an account of profits and damages, under the act of 1870, a decree was rendered in favor of the complainant, and for profits and damages as found by a master. Under the head of damages there were included items for expenses of conducting the suit, being counsel fees, compensation for the complainant's time, and interest on the profits. The decree was modified on appeal, by striking out all these allowances, except that for the complainant's time, lost in attending to the suit. Interest on profits was, on the authority of Silsby v. Foote (20 How. 378) disallowed on the ground that profits in such a case are to be regarded in the light of unliquidated damages. No injunction was decreed, as the term of the patent had expired. It does not appear from the report of the case when the suit was begun, but a reference to the original record shows that the bill was filled in April, 1871, before the expiration of the term of the patent.

Hendrie v. Sayles (98 Ü. S. 546) was a bill in equity for an account of profits, filed after the expiration of the patent, the same patent on which the present suit is founded. It was decided upon a single point raised on demurrer to the bill, the question of jurisdiction not being noticed either by counsel or court. A decree for the complainant was affirmed on appeal.

This appears to be the only case of the kind, until the present, that found its way into this court.

Eureka Company v. Bailey Company (11 Wall. 488) is no exception to this remark; although in respect to it the observation has been made, that the injunction prayed for in that case was incidental to the account, and not vice versa. That, however, is a misconception; for, unless upon the ground of a difference of citizenship, the court would not have had jurisdiction to entertain the bill in that case, if it had not prayed for an injunction. For the mere purpose of enforcing the contract for the royalty, it was not a case arising under the patent laws, so as to give jurisdiction to the courts of the United States. It was because the defendant was guilty of an infringement of the complainant's patent that he was suable in equity in these courts, and to restrain that an injunction was asked until he should pay what he had promised. The object of this suit doubtless was to collect the royalty; but it was sought by means of, and therefore as an incident to, the jurisdiction of the court, invoked for the purpose of enjoining the continuance of

what, until the royalty was acknowledged and paid, was found to be an infringement.

All the acts of Congress relating to patents prior to that of 1870 contained provisions specifying the special defences which might be made in an action at law for an infringement, under the plea of the general issue, notice thereof having been previously given. The sixty-first section of the act of 1870 enumerates the several special matters thus authorized to be proved, and adds, for the first time in the history of this legislation, the clause that "the like defences may be pleaded in any suit in equity for relief against an alleged infringement, and proofs of the same may be given upon like notice in the answer of the defendant and with the like effect."

The plain and obvious purpose of this provision is to furnish appropriate modes in equity pleading for the trial of all issues, both of fact and law relating both to the alleged infringement and the validity of the patent, without the necessity of framing special issues out of chancery for trial by jury, or sending the parties to a court of law for the trial of an action in that forum, in order to determine their legal right. It proceeds upon the idea that the court of equity having acquired jurisdiction for the purpose of administering the equitable relief sought by the bill, may determine directly and for itself, in the same proceeding, all questions incidental to the exercise of its jurisdiction, notwithstanding they may be questions affecting legal rights and legal titles.

Although this was the first statutory authority for the practice, it was rather a recognition of what had already been established than its introduction; for the practice had, in fact, originated long before, and was based upon well-known principles of equity jurisprudence. Whatever question may have existed in reference to it previously was settled in the courts of the United States by Goodyear v. Day (2 Wall. Jr. 283), a case argued by Webster and Choate, and decided by Mr. Justice Grier in 1852. That learned judge on that occasion said: "It is true that in England the Chancelfor will generally not grant a final and perpetual injunction in patent cases, when the answer denies the validity of the patent, without sending the parties to law to have that question decided. But even there the rule is not absolute or universal; it is a practice founded more on convenience than necessity. It always rests on the sound discretion of the court. A trial at law is ordered by a chancellor to inform his conscience; not because either party may demand it as a right, or that a court of equity is incompetent to judge of questions of fact or of legal titles." See also Orr v. Mer

rill, 1 Woodb. & M. 376.

The distinction in the nature of the two proceedings, of an action at law and a suit in equity, is plainly pointed out in this section of the statute, the former as being in action for an infringement, the

11 A. & E. R. Cas.-19

latter as a suit of relief against an alleged infringement. And while upon the words used in the fifty-fifth section of the act, it may be, that the jurisdiction in equity which is thereby conferred is not exhausted by the power to grant injunctions according to the course and principles of courts of equity, to prevent the violation of any right secured by patent, yet the statute immediately says, that it is upon a decree being rendered in any such case for an infringement as though that was the only one-that the complainant shall be entitled to recover, in addition to the profits to be accounted for by the defendant, the damages the complainant has sustained thereby.

It is impossible, we think, to maintain the claim that the language of this act, similar in that respect to the previous acts of 1819 and 1836, confering jurisdiction in patent cases in equity as well as at law, was meant to obliterate the distinctions between these two jurisdictions, or even to confuse the boundaries between them, as it is alleged was done by the decision in the case of Nevins v. Johnson (3 Blatchf. 80), and perhaps in other subsequent circuit court decisions. Indeed, it is the settled doctrine of this court that this distinction of jurisdiction, between law and equity, is constitutional, to the extent to which the seventh amendment forbids any infringement of the right of trial by jury, as fixed by the common law. And the doctrine applies in patent cases as well as others. This court said in Parsons v. Bedford (3 Pet. 433), speaking of the meaning intended by the framers of that amendment, that "by common law they meant what the Constitution denominated in the 3d article, law, not merely suits which the common law recognized among its old and settled proceedings, but suits in which legal rights were to be ascertained and determined, in contradistinction to those where equitable rights alone were recognized and equitable remedies administered." The rule was repeated in Fenn v. Holme (21 How. 481), in this language: “In every instance in which this court has expounded the phrases, proceedings at the common law and proceedings in equity, with reference to the exercise of the judicial powers of the courts of the United States, they will be found to have interpreted the former as signifying the application of the definitions and principles and rules of the common law to rights and obligations essentially legal; and the latter as meaning the administration with reference to equitable as contradistinguished from legal rights, of the equity law as defined and enforced by the Court of Chancery in England. It becomes necessary, therefore, to consider what support there is in the general doctrines of equity for the contention of the appellant.

It is the fundamental characteristic and limit of the jurisdiction in equity that it cannot give relief when there is a plain and adequate and complete remedy at law; and hence it had no original,

independent, and inherent power to afford redress for breaches of contract or torts, by awarding damages; for to do that was the very office of proceedings at law. When, however, relief was sought which equity alone could give, as by way of injunction to prevent a continuance of the wrong, in order to avoid multiplicity of suits and to do complete justice, the court assumed jurisdiction to award compensation for the past injury, not, however, by assessing damages, which was the peculiar office of a jury, but requiring an account of profits, on the ground that if any had been made, it was equitable to require the wrong-doer to refund them, as it would be inequitable that he should make a profit out of his own. wrong. As was said by Vice-Chancellor Wigram in Colburn v. Simms, 2 Hare, 543, "the court does not by an account accurately measure the damage sustained by the proprietor of an expensive work from the invasion of his copyright by the publication of a cheaper book," but, "as the nearest approximation which it can make to justice, takes from the wrong-doer all the profits he has made by his piracy and gives them to the party who has been wronged."

Whether a bill for an account of profits against a wrong-doer would lie, independently of other equitable grounds for the intervention of the court, is a question, as was said by Lord Chancellor Brougham in Parrott v. Palmer, 3 Myl. & K. 632, "which has been oftentimes agitated, and has, perhaps, never received a clear and a general decision; that is to say, a distinct judgment on the general proposition, with its limitations." He concluded that, from the whole it may be collected that, although as to timber there exists considerable discrepancy, yet the sound rule is to make the account, the incident and not the principal, where there is a remedy at law; but that mines are to be otherwise considered, and that as to them the party may have an account even in cases where no injunction would lie."

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The supposed exception in cases of mines seems to rest upon a dictum of Lord Hardwicke in Jesus College v. Bloom, 3 Atk. 262, that "it was a sort of trade;" but the reference is to the case of Bishop of Winchester v. Knight, 1 P. W. 406, where the bill prayed for an account of ore dug by the ancestor of the defendant, in respect to which the argument was that being a personal tort it died with the person. The decision was that the plaintiff was not entitled; but on this point the Lord Chancellor said: "It would be a reproach to equity to say, where a man has taken my property, as my ore or timber, and disposed of it in hie lifetime and dies, that in this case I would be without remedy. It is true as to the trespass of breaking up meadow or ancient pasture ground, it dies with the person; but as to the property of the ore or timber, it would be clear, even at law, if it came to the executor's hands, that trover would lie for it; and if it has been disposed of in the