after stating the facts as above, delivered the opinion of the court.
It was old in the telephone toll-station art to employ means for imparting signals from the pay-box to the transmitter of a telephone. This was attained in several ways. It would be electrically effected by the employment of a coin in making or breaking the circuit, thereby at once advising the central office, or by operating the signal device from the central office, or by depositing a coin in the channel provided for that purpose, so arranged as to cause a bell or gong to sound. We have to do only with this latter device.
It seems to have been assumed that the signal could be conveyed to the transmitter through air waves alone. With this in view, various conductors were employed whereby the sound or signal was projected upon the diaphragm of the transmitter from the outside.
Complainant claims to have been the first to utilize the principle of solid vibration. Its patent first above named is for a device in which the signal is given to the transmitter by means of resonant connection between the signal or pay box and the transmitter-support, thereby avoiding all appliances which employ the air waves for that purpose. So far as the record discloses, such a device is desirable, being both effective and simple. In view of the art and the advantage to the public of every advance therein tending to better service, there seems to be little doubt that, if the patentee was the first to disclose a toll station employing this means of operating the transmitter, he and his assigns are entitled to the protection of a court of equity, unless they have in some waj' waived their rights. There are several patents in the prior art, which, in a degree at least, might well have been claimed, though unconsciously to their inventors, to have afforded the assistance of the vibration caused b}' resonant contact of the signal-box with the transmitter-support. The various signaling methods referred to, wherein the sound is conveyed by deflectors or other means for impacting upon the transmitter-diaphragm through the air, would undoubtedly, if so arranged as to permit of vibration, be supplemented directly, if indeed the vibration were not the principal channel of sound conduction to the transmitter, as, for instance, Gray’s several patents, Nos. 469,-649, 469,650, 462,813, and Root patent, No. 440,118, and Holbrook patent, No. 481,903. Owing to the fact that the signal-box and transmitter-support have a common backboard, even though they be not in actual close contact, there could hardly fail to be some degree of vibration through the limited resonant connection. Granting this to be *421the case, yet the patentees neither made claim for such a result, nor sought to take advantage thereof, and the record fails to make it apparent that any satisfactory and practical results could have been obtained thereby.
“A patent for a mechanical combination is not anticipated by a drawing in a prior patent which incidentally shows a similar arrangement of parts, where such arrangement is not essential to the first invention, and was not designed, adapted, or used to perform the function which it performs in the second invention, and where the first patent contains no suggestion of the way in which the result sought is accomplished by the second inventor.” Brill v. Third Ave. R. C. (C. C.) 103 Fed. 289.
As was said in Canda v. Michigan Iron Company, 124 Fed. 486, 61 C. C. A. 194:
“But if the patent gives no sign of such contemplated use and makes no provision adapting it to other uses, the patentee cannot he said to have invented that for which he lias given no specific directions for construction. * * * II. (the patent there in suit) was not constructed, with a view to tshe special purpose of the patent in suit. It is true that it might happen that a casing would he made under the Hardy patent which would he adapted to the use contemplated by Canda; but, if so, it would be merely accidental. It would not result from any preconception nor from anything specifically directed by the patent for organizing his invention.”
Defendant cites Gentry patent, No. 516,433, granted March 13, 1894, for a telephone toll station, and Alexander patent, No. 544,077, granted August 6, 1895, for improvement in coin-signal apparatus for telephone pay stations. The application for the patent in suit was filed November 17, 1893. It thus appears that at the time the application for the patent in suit was filed these two alleged anticipating patents were not in the prior art, and cannot be availed of as anticipations. Bates v. Coe, 98 U. S. 31, 25 L. Ed. 68; Anderson v. Collins, 122 Fed. 451. 58 C. C. A. 669 ; Eck v. Kutz, 132 Fed. 758; Walker on Patents, § 70; Robinson on Patents, § 331, and note, 332, 334; Barnes v. Sprinkler Co., 60 Fed. 605, 9 C. C. A. 154.
It is insisted by defendant that, even though the rule be as above stated, the fact that the patentee amended his application on July 1, 1896, by substituting the words “firm” or “firmly” in place of the words “close contact,” and inserting, after the words “transmitter-support,” the phrase, “thereby establishing a resonant connection between the signal within the box and the transmitter located outside thereof,” leaves these patents in the prior art as to the matters contained in the amendment. Theretofore the patentee had always used the term “close contact” to indicate a path of practical vibratory travel for the signal. To avoid any uncertainty as to his meaning, he substituted the word “firm.” There never was any doubt in the mind of any one, and certainly not in the mind of any one skilled in such matters, as to the meaning of the phrase “close contact.” The context, as well as the avowed object to attain sound travel from the signal to the transmitter, made it clear that the term first used meant just what was expressed in the amendment. Therefore the substitution of the word “firm” can be viewed as nothing more than an elaboration of the idea, and in no sense a new feature. There is therefore nothing in the record to warrant the consideration of either of these two patents as an anticipation.
Gray was the first to devise and construct a toll station based upon the idea that the pay-box signal should be communicated to the trans*422mitter by means of resonant connection between the two. He took steps to secure the utmost freedom of vibration from one to the other. His means of doing so involved a firm or rigid relation of the one to the other — such as would afford the most complete vibratory medium. This would never have been achieved without the idea of vibratory conduction of the sound signal along the solid wood or metal located in the path of vibration between the signal and the transmitter. The accidental vibration growing out of the constructions of the prior art would never have developed reliable vibratory communication. Accuracy of enunciation is the end toward which telephony is striving. Every step in advance is a victory gained over the unknown. The invention must of necessity, if it be such, consist in the device of the patent, and not in the conception of the principle to be utilized. Sewall v. Jones, 91 U. S. 171, 23 L. Ed. 275. But the conception must precede the adaptation to practical use. While the properties of wood and metal as conductors of sound were matters of general knowledge, it cannot be said that the harnessing- of this natural principle to the telephonic service was known to be practicable or practical — else why the long-continued employment of the clumsy and inconvenient deflectors and signal-box openings. We deem invention conclusively established.
. A more serious difficulty is disclosed by the file wrapper and contents. From the statement of facts it appears that the patentee made application for a device, the main feature of which was the resonant connection between the signal-box and the transmitter-support. Claim 1 called for the signal produced by a falling coin in terms. Claim 2 called for it only by reference to the specification. Both contemplate a signaling device arranged with a view to obtaining the most effective vibratory connection between the signal and the transmitter. Through the objections of the examiner in charge, the patentee amended his .claims from time to time, dwelling at each step more and more upon the details of the signal device, which was not new, but never yielding his claim for the discovery of a toll station in which the signals should .be communicated to the transmitter through vibratory action upon the signal-box and transmitter-support.
In the course of his attempts to save his idea, while seeking to meet the demands of the examiner, he seems several times to have come perilously near recantation. His struggle is apparent at every step. Notwithstanding the seeming abandonment of his basic claim- by counsel, he continually returns to it, and is at last defeated by the examiner. On appeal to the Examiner in Chief, the application was considered upon the question of patentable novelty involved in constructing a toll station in which the signals are -conveyed to the transmitter by vibration in a path through solid materials as contrasted with the employment of air waves, as in the prior art. The details of arrangement of the signal and signal-box are not referred to, but evidently are deemed mere incidents of a plan to dispose of the signals in such a manner as to attain the best possible vibratory results. There is no intimation that the applicant was limited in any way by the concessions made to the examiner in respect to the particular signaling device. Nor in our judgment should there have been any. On hearing had, the examiner was reversed, and the patent granted with the statement:
*423“There is tiras a new nncl simple oonsmiction by which better results are obtained, and which in our opinion requires invention to devise.”
We are therefore of the opinion that complainant is not limited to the particular form o £ signal production named in the claim under consideration, and that the patentee did not part with his right to a patent based upon his invention oí the new method of transmitting signals from the signal-box to the transmitter, by reason of any steps taken in the Patent Office.
If we are correct in our conclusion that Gray was the first inventor of a device designed to take advantage of the vibration path through the solid substances of the signal-box and transmitter-support, regardless of the specific form in which the signal-box is operated, then it follows that claim 1 of the second patent in suit, Gray No. 598,610, if valid at all, must be very narrow. The complainant’s brief fails to point out any invention, but is confined to a description of its form. Nor does the evidence disclose anything new other than the material used and the relative location of the signal-box and the transmitter. Defendant charges complainant with having, prior to the proceedings herein, treated this patent as its basic invention. It appears to effectuate complete vibratory relations between the desired parts of the toll station, hut differs only in degree from the claim of the first patent with reference to the substance thereof. It surely would be deemed to infringe the first patent in the hands of a stranger. Complainant contends there has been no attempt to anticipate this patent. The reason would seem to he that it is substantially the same as the first patent. '
Defendant asserts that if the first patent in suit is to be construed broadly, then it will not he permissible to operate under the expired patents of the prior art. There is nothing in the case to justify such a statement. When construed as above indicated, the prior patents cannot be held to affect the subject-matter.
The defendant denies infringement in fact and sets up acquiescence on the part o£ complainant. With regard to the latter claim, complainant insists its acquiescence ivas with reference to the arrangement of the signal-box. Defendant claims that the alleged infringing toll station was submitted to and approved by complainant. Of course, if defendant’s contention he true, and the device submitted disclosed the appropriation of the resonant contact idea, then complainant may not now retract and claim damages. It seems hardly credible that complainant could have inspected defendant’s complete device B, and found no infringement.
An inspection of defendant’s physical exhibit, “Baird Triplet pay station,” discloses the fact that the so-called “pay station” consists of that part of the apparatus which has hereinabove been designated as the “signal-box.” There is nothing in the exhibit or in the record which would justify us in holding that the sample box sent complainant for inspection contained any feature which would be calculated to advise complainant that defendant intended to appropriate the gist of the patent in suit. For all that appears, defendant might have been contemplating the use of the deflector, or some other feature of the prior art. The record is very scant upon the matter and certainly cannot be held to make a case of estoppel.
*424That defendant’s pay station complete is an infringement of the first patent in suit we entertain no doub.t. All three of the machines shown’ in the record involve the principles and construction of the Gray patent. Wherein there is any difference, the rule as to equivalents obtains.
The decree of the Circuit Court is therefore reversed as to Gray patent, No. 593,720, with directions to enter a decree in favor of appellant-complainant for the relief sought in its bill, in conformity with the foregoing opinion. For the reasons above stated, the judgment of the court below dismissing the bill as to Gray patent, No. 598,610, is affirmed.