If

that pulley, we have substantially the exerciser of defendant. two pulleys widely separated be substituted for the one lower central pulley in complainant's apparatus and the cord be pinned to each of these, we would again have substantially the apparatus made by defendant. In either case defendant's apparatus would be "a cord elastic throughout its entire length having pulleys thereon "-namely, the two upper pulleys-"over which the elastic cord travels." The function of complainant's apparatus in large part is not dependent on the play over the lower pulley, the cord at that point remaining stationary. In other words, the function, utility, or result of defendant's apparatus is contained in that of complainant. It makes no difference that defendant has chosen to cut the cord at the lower pulley and then secured the two ends. He might as well have pinned it to the pulley without cutting it. An infringement is not avoided because the infringing device is better, more useful, and more acceptable to the public than that of the patent infringed, nor, on the other hand, because the infringing device by some colorable variation or expedient merely impairs or narrows the function and usefulness of the device infringed. The injunction may issue as prayed.

[Supreme Court of the United States.]

BELKNAP et al. v. SCHILD.

Decided February 3, 1896.

74 O. G., 1121.

1. SCHILD-CAISSON-GATE-VALID-INFRINGED-INJUNCTION REFUsed.

Letters Patent No. 287,178, granted October 23, 1883, to George Schild, for au improvement in caisson-gates, Held to be valid and infringed, but injunction refused.

2. SAME-SAME-INFRINGEMENT BY THE UNITED STATES-SUING.

The United States have no more right than any private person to use a patented invention without license of the patentee or making compensation to him, but they cannot be impleaded in a judicial tribunal except so far as they have consented to be sued.

3. SAME-SAME-SAME-OFFICERS OF THE UNITED STATES.

The United States having, by act of Congress, consented to be sued upon their contracts, may accordingly be sued by a patentee for their use of his invention under a contract made with him by the United States or their authorized officers. 4. SAME-SAME-SAME.

But the United States have not consented to be liable to suits founded in tort for wrongs done by one of their officers, though in the discharge of his official duties. They are therefore not liable to a suit for an infringement of a patent, that being an action sounding in tort.

5. SAME-SAME-SAME.

A public officer is not personally liable on a contract made by him in the line of his duty and on account of the United States and enuring to their benefit and not to his own; but he is personally liable to be sued for his own infringement of a patent.

6. INFRINGING DEVICE-PROPERTY OF THE UNITED STATES-USE BY OFFICERSPARTY TO SUIT.

Where the infringing device was the property of the United States and held and used by them for the public benefit through officers, the United States were an indispensable party to the suit to enable the court to grant the relief sought. 7. INFRINGEMENt-Benefits, tO WHOM ACCRUING-RECOVERING Profits.

“In a suit in equity for the infringement of a patent, the ground upon which profits are recovered is that they are the benefits which have accrued to the defendants from their wrongful use of the plaintiff's invention, and for which they are liable, ex aequo et bono, to the like extent as a trustee would be who had used the trust property for his own advantage. The defendants, in any such suit, are therefore liable to account for such profits only as have accrued to themselves from the use of the invention, and not for those which have accrued to another, and in which they have no participation."

8. DISSENTING OPINION.

Mr. Justice Harlan did not concur in the disposition which was made of the

case.

APPEAL from the Circuit Court of the United States for the Northern District of California.

Mr. Holmes Conrad for the appellants.

Mr. M. M. Estee, Mr. W. W. Dudley, Mr. L. T. Michener, and Mr. J. H. Miller for the appellee.

STATEMENT OF THE CASE.

This was a bill in equity, filed January 20, 1887, in the Circuit Court of the United States for the Northern District of California, by George Schild against George E. Belknap, Joseph Feaster, Christopher O. Wolcott, and Jesse Diamond, for an infringement of Letters Patent granted by the United States to the plaintiff on October 23, 1883, No. 287,178, for an improvement in caisson-gates.

The bill alleged that the defendants, with full knowledge and in violation of the plaintiff's exclusive right, manufactured and used, and intended to continue to use, such caisson-gates in the State of California; and that he had brought an action in the same court against the Union Iron Works of San Francisco, and on the trial of that action, and, after he had waived other than nominal damages, recovered a verdict in the sum of one dollar, in August, 1886, and the validity of his patent and the fact of infringement were thereby established.

The bill prayed that the defendants be decreed to account for and pay over to the plaintiff all such gains and profits as had or might have accrued to them from purchasing or making or using such improved caisson-gates; that any further damages sustained by the plaintiff by reason of the defendants' infringement be assessed and ordered to be paid; that the defendants be restrained by injunction from making or using caisson-gates containing the patented improvement; that the caisson-gates, containing that improvement, and so manufactured, or purchased or in any manner obtained by the defendants, and now in their possession, be destroyed or delivered up to the plaintiff'; and for further relief.

The defendants filed a plea to the whole bill, (called in the record a "plea in abatement,") alleging that the court "ought not to take cognizance of or sustain the aforesaid action," for that the defendant Belknap was a commodore in the United States Navy, and commandant of the United States navy-yard at Mare Island, California; that the defendants Wolcott, Feaster, and Diamond were, respectively, a civil engineer in the Navy, an assistant naval constructor in the Navy, and an employé of the United States at Mare Island; that the only caissongate which either of the defendants had any relation with, control over, or use of, within the State of California, was one constructed, manufactured and used by the Government of the United States and for their use and benefit at the navy-yard at Mare Island, and was there built by the Union Iron Works, in pursuance of plans and specifications furnished by the Bureau of Yards and Docks, a board in the naval service of the United States, and was delivered by the Union Iron Works to the United States, and used by the United States in the drydock of that navy-yard; and that neither the defendants, nor either of them, made or constructed the caisson-gate in question, or used it for their own use and benefit, or ever had, or pretended to have, any interest in or claim upon it; but that they only operated and used it as the officers, servants and employés of the United States, as a part of the navy-yard, and for public uses of the United States, in the exercise of their sovereign and constitutional powers.

The Attorney-General of the United States, appearing for this purpose only, filed a suggestion, (called in the record a "plea to the jurisdiction,") in which he stated that the caisson-gate in question was planned and constructed by the United States, and ever since its construction had been in the possession, control and use of the United States at the navy-yard at Mare Island, and was operated at the drydock in the navy-yard for naval purposes and the public defense, in the building and repairing of ships for the Navy of the United States; that the United States. through their officers and agents, charged with the possession, control and operation of that navy-yard, had at all times been in possession, control and operation of the caisson-gate as public property of the United States, for public uses, in the exercise of their sovereign and constitutional powers; and that the defendants, and each of them, never had anything to do with the construction, use or operation of the gate, or made any claim of right, title, possession, control or use of it, other than as officers and agents of the United States, and in obedience to orders of the naval department of the Goverument; and therefore

without submitting the rights of the United States to the jurisdiction of the court, but insisting that the court has no jurisdiction of the controversy, for that the said caisson-gate and its use now is and at all times has been the property of the United States

moved that the bill be dismissed, and all proceedings stayed and set aside.

The case having been submitted to the court upon the plea of the defendants, and the suggestion of the Attorney-General, both were overruled.

The defendants, Belknap, Feaster, Wolcott, and Diamond, then filed an answer, admitting the grant of the Letters Patent, denying the infringement, setting forth affirmatively the matters stated in their former plea, and alleging that neither these defendants nor the United States were parties to the action brought by the plaintiff against the Union Iron Works, or estopped by the judgment therein.

A general replication was filed; and evidence was taken, by which it appeared that the validity of the plaintiff's patent, and its infringement by the defendants, were subjects of conflicting testimony; that Mare Island and the works and dock thereon, including the caisson-gate, belonged to the United States, and were held and occupied for them by their officers and employés; that the defendants respectively held the positions stated in their former plea and had no interest in the caissongate, and nothing to do with it beyond operating it under the direction of the United States; that the gate was built in 1884, without any agreement or license of the plaintiff, by the Union Iron Works under its contract with the United States, and according to plans and specifications furnished by the Bureau of Yards and Docks, and Wolcott simply inspected the materials and workmanship, as the work progressed, to see if they were according to the contract; and that the gate had since been used by the United States, as part of the dock in the navy-yard aforesaid.

After a hearing upon pleadings and proofs, the court made an interlocutory decree, adjudging that the patent was valid, and had been infringed by the defendants; referring the case to a master to take an account of the number of caisson-gates made or used by the defendants, or either of them, in violation of the patent, and also of the gains, profits and advantages, arising or accruing to the defendants or either of them, and of the damages sustained by the plaintiff; and ordering a perpetual injunction against the defendants and each of themand their and each of their agents, servants, clerks, and workmen, and all persons elaiming or holding under or through them or either of them.

The master reported that one caisson-gate to the dock in the navyyard at Mare Islaud, for the making and using of which the defendantshad been adjudged to have infringed the plaintiff's patent, had been made upon plans furnished by the plaintiff and modified by the Government officials, and put in use in 1884; that the cost of this gate was $60,000, and the cost of the cheapest practicable gate, constructed on any other plan known to the defendants, would be at least $100,000, and therefore the gains, profits and advantages, which had arisen and accrued to the defendants from infringing the plaintiff's patent, amounted to $40,000; and that no damages, in addition to such gains, profits and advantages, had been proved.

The court overruled exceptions taken by the defendants to the

master's report, confirmed his report, and entered a final decree for the plaintiff for the sum of $40,000, with interest and costs. The defendants appealed to this Court.

Mr. Justice GRAY, after stating the case, delivered the opinion of the Court.

A recapitulation of the principles heretofore affirmed by this Court, touching the liability of the United States, and of their officers and agents, to suit in the judicial tribunals, will go far toward disposing of this case.

It should be premised that our law differs from that of England as to the right of the Government to use, without compensation, an invention for which it has granted Letters Patent.

In England, the grant of a patent for an invention is considered as simply an exercise of the royal prerogative, and not to be construed as precluding the Crown from using the invention at its pleasure; and therefore a petition of right cannot be maintained against the Crown for using a patented invention; although a private person or corporation, that has contracted to supply the Government with articles embodying the invention, may be sued for infringement of the patent. (Feather v. The Queen, 6 B. & S., 257; Dixon v. London Small Arms Co., L. R. 10 Q. B., 130, and 1 App. Cas., 632.)

But, in this country, Letters Patent for inventions are not granted in the exercise of prerogative, or as a matter of favor, but under article 1, section 8, of the Constitution of the United States, which gives Congress power

to promote the progress of science and useful arts, by securing for limited terms to authors and inventors the exclusive right to their respective writings and discoveries.

The patent act provides that every patent shall contain a grant to the patentee, his heirs and assigns, for a certain term of years, of— the exclusive right to make, use and vend the invention or discovery throughout the United States. (R. S., 4884.)

And this Court has repeatedly and uniformly declared that the United States have no more right than any private person to use a patented invention without license of the patentee or making compensation to him. (United States v. Burns, 12 Wall., 246, 252; Cammeyer v. Newton, C. D., 1877, 182; 11 O. G., 287; 94 U. S., 225, 235; James v. Campbell, C. D., 1882, 67; 21 O. G., 337; 104 U. S., 356, 358; Hollister v. Benedict Manufacturing Co., 113 U. S., 59, 67; United States v. Palmer, 128 U. S., 262, 270-272.)

The United States, however, like all sovereigns, cannot be impleaded in a judicial tribunal, except so far as they have consented to be sued. This doctrine has been affirmed by this Court in cases too numerous to be cited; and was clearly stated by Mr. Justice Field, delivering judg ment in the case of The Siren, as follows:

It is a familiar doctrine of the common law, that the sovereign cannot be sued in his own courts without his consent. The doctrine rests upon reasons of public