delivered the opinion of the court..
The stress of this-base is upon the question of /patentable. *14novelty. The art of insulating electric wires has been known almost as- long as that of conducting electricity for practical purposes by means of wires. Prior to the use of electricity for lighting, however, the feeble character of the currents conveyed upon these wires did not require that the insulating material should be non-combustible, and the skill of the inventor was directed toward a method of insulation which should protect the wire from moisture and other external injury. For this purpose the wires were covered with braid which had been saturated or covered with tar, paraffine, india-rubber, gutta-percha, asphaltum and various substances of like nature, to exclude "the action of the water and afford a proper insulation.
Upon the introduction of electric lighting it was found that this method of insulation, while efficient to protect the wire from external influences, was unable to withstand the intense heat frequently generated in the wire itself by the- powerful currents of electricity necessary-for illuminating purposes. At first these wires were covered with cotton which had been saturated in paraffine and other similar substances; the result was that the insulating material was melted or set on fire, and dropped off the wire while still burning, and became so frequently the cause of conflagrations that the insurance companies declined to issue policies upon buildings in which this method of insulating wires was employed. A new substance was needed which would not only operate as a non-conductor of electricity, and as a protection against moisture, but .which should also be non-combustible.
This material was discovered in ordinary paint. Mr. Cowles was not the first, however, to discover that paint was useful for the purpose of insulating electric wires. In several English patents put in evidence, paint is suggested as a proper covering for protective as well as for insulating purposes, in lieu of gutta-percha, india-rubber, resin, pitch or other similar substances, but as a non-combustible insulator was never required for telegraphing purposes, there is no intimation in any of them that it possessed this quality. It had, however, been a matter of .common.knowledge for many years that paint was *15practically non-combustible. While the linseed oil in paint is to a certain extent combustible, the carbonate of lead is a material both non-combustible and a non-conductor.
It is clear that none of these English patents can be claimed as anticipations, since they all relate, to the protection of land pr submarine telegraph cables, and the use of paint, so far as it was used at all, was simply as a water-proof covering for a braided wire. There is nothing to indicate that the paint, as used by them, was applied in the manner indicated by the patent, or that it made the covering non-combustibie, or was intended at all for that purpose.
The most satisfactory evidence of the use of a non-combustible covering for electric wires is found in the testimony of Edwin Holmes, manufacturer of an electric burglar alarm, who states that when he first commenced using electric conductors “ the wire was insulated by winding a thread, larger or smaller as the case might be, around the wire, and that thread was covered with paint,” and that all his wires were “ insulated in that way until paraffine was substituted for the paint.” The paint was applied by drawing the wire through a vessel containing the paint, and. then through a piece of thick' rubber or gutta-percha, which removed the surplus paint and left a smooth surface on the thread which covered the wire. He began to cover his wires in this way as early as I860, and says that he accomplished his insulation “ sometimes by covering the wire with a thicker thread and two coats or more of paint; sometimes by a thread covering and a coat of paint, then another-’thread covering and a coat of paint on that.” And upon being asked to describe the condition of the first coating of paint when the second coating of fibrous material and paint was put on, he said: “ The first coat was partially dried, so as to keep its place, but would admit of an impression from the next covering of thread.” On being called upon subsequently for an affidavit to be used on an application for a rehearing, he stated that his object was not to- produce a non-inflammable wire, and that the wire used by him was not noncombustible or non-inflammable, and was no better adapted for electric light conduction than the paraffine-coated wire. He *16further stated that when the second layer of braid wa^ laid on’ the condition of the first layer was not such as to cause the threads of the second layer to force the paint into the interstices, and so load the wire with an abnormal quantity of paint, as is done in the process described in the Cowles patent. The substance of his testimony in this particular was, that the coating of paint upon his first layer was allowed to harden before the. second layer was applied, so that the application of the second layer would not cause the paint upon the first layer to be forced into the interstices of that layer or to ooze through the braiding of the second layer.
Thomas L. Need, another witness, gaye a somewhat similar experiment of the method of insulating wires by passing the naked wire through a tub containing paint, then braiding it, and then immersing it in a second tub containing paint, and finally passing it through jaws to scrape off the surplus paint and compress it. As this method of insulation, however, does not resemble so closely the Cowles patent as that employed by • Mr. Holmes,' it is unnecessary to notice it further.
Practically the only difference between the Holmes and Cowles insulators is in the fact that the coat of paint applied to the first braid in the Holmes process was allowed to dry before the second coat of braid was applied, and thereby the braid was not so thoroughly permeated with the' paint as is the case in the Cowles patent. ’ That the idea of applying the second coat of braiding upon the interposed insulating material, while such material was wet or unset, is not in itself a novel, one is evident from the English patents to Brown • and liams, .to Duncan and to Henley, all of which describe a method for insulating conductors by applying a layer of fibrous material, a layer of insulating material, and a second layé# of fibrous material upon the former, before the insulating material is set or hardened. Indeed, it is doubtful whether Cowles, Considered this feature of his process as of any great importance-at the time he made his application, since he speaks of it only as a preferable method, and says that he does not limit himself in this particular, “ as the paint may be dried, or partially so, before the next layer of braiding is applied.”' But however *17this may be, the method described by Cowles differs only in. degree and not in kind from that described by Holmes. In other words, it is a more thorough doing of that which Holmes had already done, and, therefore, involving no novelty within the meaning of the patent law. Indeed, we are not satisfied that the method employed by Holmes did not, for all practical purposes, saturate the first layer of braid as completely as if the second coat had been applied while' the first was still wet. The process and the results in both cases are practically the same, viz.: protection insulation and incombustibility. • There were certain affidavits introduced which tended to show that the Holmes insulator was not incombustible; but in view of the experiments made by Mr.- Earle, the defendant’s expert, by applying the same current of electricity to wires insulated' by these different methods, we incline to the opinion that the method practised by Mr. Holmes was nearly, if not quite, as efficient in this particular as the other. If his testimony b,e true,'and no attempt is made to show that it is not, it is difficult to see, even if his insulator were not incombustible, that Mr. Cowles did more than make use of his process in a somewhat more efficient manner.
In the case of Gandy v. Main Belting Company, recently decided, 143 U. S. 587, the patentee found that the canvas theretofore manufactured was unfit for use as belting by reason of its tendency to stretch, and .to obviate this he changed the constitution of the canvas itself by making the warp threads heavier and stronger than the weft; in short, he made a new' canvas constructed upon new principles, and accomplishing a wholly new result. That case is not a precedent for this'.'
It is true that the insulator used by Holmes was not intended to be, and perhaps was not known to be, incombustible, since this feature of its incombustibility added nothing to its value for protecting a burglar-alarm wire, which carries a current of comparatively low tension; but, as already observed, the testimony indicates that the insulator employed by him was in fact nearly, if not quite, as incombustible as that made by the plaintiff under the. Cowles patent. If this be so,- and *18the two insulators are practically the same in their method of construction, it is clear that Cowles has no right to claim the feature of incombustibility as his invention, since nothing is better settled in this court than that the application of an old process to a new and analogous purpose does not involve invention, even if the new result had not before been contemplated. It was said by Chief Justice Waite in Roberts v. Ryer, 91 U. S. 150, 157, that “ it is no new invention to use an old machine for a new purpose. The inventor of a machine is entitled to all the uses to which it can be put, no matter whether he had conceived the idea of the use or not.”
In Pennsylvania Railway v. Locomotive Truck Co., 110 U. S. 490, 494, the adoption of a truck for locomotives which allowed a lateral motion was held not to be patentable, in view of the fact that similar trucks had been used for passenger cars. All the prior cases are cited, and many of them reviewed, and the conclusion reached that “ the application of an old process or machine to a similar or analogous subject; with no change in the manner of application and no result substantially distinct in its nature, will not sustain a patent, even if the new form of result had not before been contemplated.” The principle of this case was expressly approved and adopted in that of Miller v. Foree, 116 U. S. 22, and has been frequently applied in the administration of patent law by the Circuit Courts. Crandall v. Watters, 20 Blatchford, 97; Ex parte Arkell, 15 Blatchford, 437; Blake v. San Francisco, 113 U. S. 679; Smith v. Elliott, 9 Blatchford, 400; Western Electric Company v. Ansonia Co., 114 U. S. 447; Spill v. Celluloid Manufacturing Co., 22 Blatchford, 441; Sewall v. Jones, 91 U. S. 171.
On the other hand, if an old device or process be put to a new use which is not analogous to the old one, and the adaptation of such process to the new use is of such a character as to require the exercise of inventive skill to produce it, such new use will not be denied the merit of patentability. That, however, is not the case here, since the Cowles process had been substantially used by Holmes for the same purpose of insulating an electric wire, and the discovery of its incom*19bustible feature involved nothing that,was new in its use or method of application.
The utmost that can be said for Cowles is that he produced a somewhat more perfect article than Holmes, but as was said by this court in Smith v. Nichols, 21 Wall. 112, 119 a mere carrying forward, or new or more extended application of the original thought, a change only in form proportions or degree, the substitution of equivalents, doing substantially the same thing in the same way by substantially the same means with better results, is not such invention as will sustain a patent.”. - It was held in this case that where a* textile fabric, having a certain substantial construction, and possessing essential properties, had been long known and in use, a patent was void when all that distinguished the new fabric was higher finish, greater beauty.of surface, the result of greater tightness of weaving, and due.to the observation ór skill of the workman, or to the perfection of the machinery employed. See also Morris v. McMillin, 112 U. S. 244; Busell Trimmer Co. v. Stevens, 137 U. S. 423, and cases cited.
The decree of the Circuit Court is, therefore,
Affirmed.
Mr. Justice Field dissented.