Opinion of the Court. upon a torsional spring, and adjusting screws for regulating the amplitude of the lever movement, and the retractile resistance of the torsional spring. They are used for purposes which differ principally in name. The key transmits the message, the sounder receives it. The material part of the key is a lever which completes and breaks an electric circuit; the sounder consists merely of a lever which completes and breaks a magnetic circuit. In both cases, the lever is riveted to and supported by a flat torsional spring, which is itself supported at its ends upon upright posts, to which it is fastened by screws. The object of the spring in each instance is to allow the lever to play back and forth between the exceedingly narrow limits fixed by the set screws. The employment of this spring in connection with the sounder is such a new or double use as would occur to an ordinary mechanic who had seen the Edwards key in operation. It brought into play no faculty of invention. While the promotion of an old device, such, for instance, as a torsional spring, to a new sphere of action, in which it performs a new function, involves invention, the transfer or adaptation of the same device to a similar sphere of action, where it performs substantially the same function, does not involve invention. Against this new and analogous use of his combination, the patentee is as much entitled to protection as if the word "sounder" had been expressly inserted in his claim. Since the case of Winans v. Denmead, 15 How. 330, it has been the settled doctrine of this court, as expressed in the opinion of Mr. Justice Curtis, p. 343, that "the patentee, having described his invention and shown its principles, and claimed it in that form which most perfectly embodies it, is, in contemplation of law, deemed to claim every form in which his invention may be copied, unless he manifests an intention to disclaim some of these forms." This is practically restated in different language in subsequent cases, and amounts to a declaration that the application of the patented device to another use, where such new application does not involve the exercise of the inventive faculty, is as much an infringement as though the new machine were an exact copy of the old. Sewall v. Opinion of the Court. Jones, 91 U. S. 171, 183; Howe v. Abbott, 2 Story, 190; Walter v. Potter, Webster Pat. Cas. 585. Some stress is laid by the defendant upon the fact that the "circuit-breaking" lever is made an ingredient of the first, second and fourth claims of the patent, and that as the sounder has no circuit-breaking lever, but only an armaturelever, there is no infringement. Assuming, however, what as a matter of fact seems doubtful, that the lever of the sounder is not a circuit-breaking lever, the objection loses all its force in view of the language of the third claim, the only one found to be infringed, in which the limitation of the circuit-breaking lever is omitted, and a "lever fulcrumed upon the torsional spring" is substituted. The further objection that in the defendant's sounder a retractile spring is used in aid apparently of the torsional spring, suggests rather than justifies an argument that the torsional spring is useless, and that the sounder would be inoperative without the retractile spring. If such were the fact, it would be an excellent reason for discontinuing the use of the torsional spring, and thereby avoiding beyond all question the charge of infringing the patent. But, notwithstanding the testimony of Mr. Haskins, that he found the best results to be obtained when the torsional spring was simply passive, allowing the armature to lie with its own weight upon the magnet, depending wholly upon the retractile spiral spring underneath to produce the upward movement, the fact seems to be that the defendant's sounder will operate about as satisfactorily if only the torsional spring is used. And even if the defendant does use the retractile spring in aid of the torsional spring, it could not thereby escape the charge of infringement. The object of the torsional spring is not only to do away with the necessity of a retractile spring, but to substitute for the ordinary pivotal bearings the torsional support. Giving Haskins's testimony its full weight, it still remains uncontradicted that he does use the torsional spring as a substitute for the trunnions or pivots theretofore used to support the lever. The claim that defendant does not use the adjusting screws is equally without foundation. Indeed, this suggestion is dis Syllabus. posed of by defendant's own expert, who testifies to finding adjusting screws having a relation to the sounder similar to that of the screws H H' to the lever of the key in the patent, but he says that in the sounder they did not appear to have any effect upon the retractile force applied to the lever. It is evident, on examination, that their functions are practically the same in every particular. The last defence of want of utility is also fully met by the fact that Haskins, an employé of the defendant, after the commencement of this suit, took out the patent for a telegraph sounder, the main element of which is the torsional spring of the Edwards patent, and that defendant, upon the accounting, stipulated that a decree might be entered for a royalty of ten cents apiece, on eleven hundred sounders made and sold by the defendant embodying the Edwards invention. Under such circumstances, it does not lie in the mouth of the defendant to claim that the invention is useless. Walker on Patents, § 85; Lehnbeuter v. Holthaus, 105 U. S. 94; Morgan v. Seaward, 1 Webster Pat. Cas. 170. The decree of the court below is Affirmed. SEEBERGER v. FARWELL. ERROR TO THE CIRCUIT COURT OF THE UNITED STATES FOR THE NORTHERN DISTRICT OF ILLINOIS. No. 1441. Argued March 30, 31, 1891.- Decided April 13, 1891. Under Schedule K of § 2502 of the Revised Statutes, as enacted by § 6 of the act of March 3, 1883, c. 121, 22 Stat. 509, women's and children's dress goods, composed of wool and cotton, valued at less than 20 cents per square yard, and weighing less than 4 ounces to the square yard, the cotton being carded in with the wool from which the yarn composing the warp was spun, there being 94 per cent of wool and 6 per cent of cotton, the cotton being put in to secure a lower classification for duty, and an ordinary examiner not being able to detect the cotton without a careful examination, and there being no threads or yarns made wholly of cotton or other material than wool, are dutiable at 5 cents per square yard and 35 per cent ad valorem, and not at 9 cents per square yard and 40 per cent ad valorem. Opinion of the Court. THE case is stated in the opinion. Mr. Solicitor General for plaintiff in error. Mr. Percy L. Shuman for defendants in error. MR. JUSTICE BLATCHFORD delivered the opinion of the court. This is an action at law, brought in the Circuit Court of the United States for the Northern District of Illinois, in August, 1888, by John V. Farwell and others, copartners as John V. Farwell & Co., against Anthony F. Seeberger, collector of customs for the port and district of Chicago, to recover an alleged excess of duties, paid under protest, in that month, on a quantity of imported women's and children's dress goods, which were dutiable under the provision of Schedule K of section 2502 of the Revised Statutes, as enacted by section 6 of the act of March 3, 1883, c. 121, which provided for the following rates of duty on the following articles, after July 1, 1883, 22 Stat. 509: "Women's and children's dress goods, coat linings, Italian cloths, and goods of like description, composed in part of wool, worsted, the hair of the alpaca, goat or other animals, valued at not exceeding twenty cents per square yard, five cents per square yard, and in addition thereto, thirty-five per centum ad valorem; valued at above twenty cents per square yard, seven cents per square yard, and forty per centum ad valorem; if composed wholly of wool, worsted, the hair of the alpaca, goat or other animals, or of a mixture of them, nine cents per square yard and forty per centum ad valorem, but all such goods with selvedges, made wholly or in part of other materials, or with threads of other materials introduced for the purpose of changing the classification, shall be dutiable at nine cents per square yard and forty per centum ad valorem: Provided, That all such goods weighing over four ounces per square yard shall pay a duty of thirty-five cents per pound and forty per centum ad valorem.” The case was tried by the court without a jury. It found the issues for the plaintiffs, and assessed their damages at $3265.66; and a judgment was entered in their favor for that VOL. CXXXIX-39 Opinion of the Court. amount, with $23.16 costs, to review which the defendant has brought a writ of error. The opinion of the court is reported in 40 Fed. Rep. 529, and it made a special finding of facts, to the effect that the goods in question were composed of wool and cotton, were valued at less than 20 cents per square yard, and weighed less than 4 ounces to the square yard; that the defendant assessed a duty upon them of 9 cents per square yard and 40 per centum ad valorem; that the plaintiffs paid the duties under protest, for the purpose of obtaining possession of the goods, and in due time protested to the collector against the exaction, and seasonably appealed to the Secretary of the Treasury, who sustained the decision of the collector, and the suit was brought in due time; and that in the protest the plaintiffs claimed that the goods should have been assessed at a duty of 5 cents per square yard and 35 per centum ad valorem. The court also found that the goods were composed of wool and cotton, the cotton being carded in with the wool from which the yarn composing the warp of the goods was spun, there being about 6 per cent of cotton mixed with the wool, so that the goods were composed of about 94 per cent in quantity of wool and 6 per cent in quantity of cotton; that the cotton was mixed with the wool from which the yarn composing the. warp of the goods was spun, for the purpose of securing the classification of the goods under the clause before quoted, so that they would be dutiable at 5 cents per square yard and 35 per centum ad valorem; that the ordinary examiner of the goods would not detect the cotton without careful examination; that the goods had no selvedges of different material from the body of them, and there were no threads or yarns made wholly of cotton or other material than wool; and that it cost slightly more to manufacture the goods with such mixture than it would to make them all of wool. The court, therefore, found that the goods were composed in part of wool and part of cotton, weighing less than 4 ounces to the square yard and valued at not exceeding 20 cents per square yard. The court, in its opinion, said that the collector, in classifying the goods, evidently assumed that the purpose of mixing |