(after stating the facts as above). [1] We pass without discussion or decision the question whether the method claims of this patent are anything more than descriptions of a function of the mechanical device disclosed. In a steadily growing art, the laudatory epithets bes Lowed in the cases cited above upon the device of using the back voltage of the battery to stop overcharging seem now rather out of place. Systems of lighting substantially along Cteveling’s suggestions obtained extended use, and this record displays unanimity among practical men, that for reasons arising especially from the rough passage of cars over frogs, switches, and the like, the stop charge relay “went off” too soon.
It is plain that this was the very real problem to which the patentee addressed himself. He solved it, to put the matter most, favorably for him, and as it is put by very able counsel, by combining the potential control commonly used in 1908 in train lighting, with the ampere hour meter control already known and used in stationary plants. It is observable that Mr. Kennedy nowhere uses in his specification the term “ampere hour meter”; possibly because “ampere hour” is a term of art, meaning a certain unit of electricity, and a meter for ampere hours must mean something capable of measuring and indicating such units. He speaks only (in the claims quoted) of a “mechanism” or a “traveler.”
The language chosen was careful; for as above shown, and admitted by plaintiffs expert witness, the “mechanism” of the patent only registers and reports how many units (called ampere hours) ought *84to be in the batteries, assuming that the generator is giving (when it .gives anything) a steady volume of 30 amperes, or other precalculated •quantuip. As a meter, the device (and none other is suggested) somewhat resembles a water meter, which will tell how many gallons there are in a tank, fed by a pipe assumed to give a steady flow, and de•pleted by turncocks assumed to pass- a certain amount of liquid. Such a device is not a meter; it has no means of ascertaining and disclosing whether the assumptions are true.
The basic difference between the mechanism of the disclosure and a true meter or measurer of amperage is that the former has no member responsive to the actual battery current; it never knows what that current is doing or has done; it can only state the result of the assumptions regarding in-put and out-go which are the law of its being. The defendant’s meter is a true ampere hour measurer, responsive to the current, and indicating actual and not assumed conditions.
Applying the foregoing to the claims, the patentee’s '“traveler” does -riot “move a distance proportional to the charge in the battery”; it •only moves a distance determined by the charge that ought to be in the battery, if the generator, etc., have been functioning as expected. But his “mechanism” does render the “controlling device inoperative until the battery has been charged to a predetermined number of ampere hours,” in the sense that it delays the operation of what is essentially a “stop charge” until the battery ought to be full, and if it is not (though the indicator says it ought to be) the control will not operate until the predetermined back voltage is reached. The defendant is right in calling this mechanism a “time-delay device.”
It is no longer necessary to multiply citations to show that claims are tb be construed in the light of the contribution to knowledge actually made by the inventor, or that mere ability to fit to a thing the words of a claim does not prove infringement. Let it be assumed that (e. g.) the first claim, at least, will “read on” defendant’s system; it remains to inquire whether that (and other) claims, construed consistently with the patentee’s actual achievement, justify the finding that there has been that substantial appropriation which is always the essence of the tort known as infringement.
[2] Even the broadest or most loosely drawn method or combination claim, must be fortified by a disclosure of how the method is to he practiced, or of the kind and nature of the elements combined. The method proposed by this inventor for supplying current to battery “for a predetermined number of ampere hours” leaves the ultimate determination of the proper battery quantum to two circuit-controlling ■devices” — i. e., relays — both of which are fundamentally dependent for activity on the counter e. m. f. of the charge battery; the sole inventive thought revealed by the disclosure is to delay that action for a time that can be properly expressed in ampere hours only if the generator is working smoothly and delivering its product at a precal-culated rate.
[3] The combination disclosed, when not limited to a constant current system (as in claim 3), requires as one element (claim 7) “mech-•ánisrti ‘responsive to the current flowing in the battery circuit to move *85tlie traveler a distance proportional to the charge in the battery.” It has been already shown that in no true sense does the traveler (indicating finger) do the thing claimed; but, assuming that the combination is good for what its elements will really co-ordinately accomplish, there can be no infringement, unless defendant’s combination is of substantially the same elements functioning co-ordinately in the same way.
We fully agree with the court below that (to use the phrases of counsel) defendant’s ampere hour meter is an element wholly different from plaintiff’s time-delay device; consequently there is no appropriation of method or combination, and no infringement. Though in a much less important art there is a singular resemblance between this patent and that to Selden for an automobile. In that well-known instance, the “liquid hydrocarbon gas engine of the compression type,” which was an element in Selden’s combination, was a phrase as all-embracing as the “mechanism” of this one. Yet, where patentee plainly had only one type of engine (or “mechanism”) in mind, varying the combination by employing an entirely different engine typq was held to avoid infringement. Columbia, etc., Co. v. Duerr, 184 Fed. 893, 107 C. C. A. 215.
[4] The argument has been much pressed that Kennedy’s disclosure reveals nothing useful, and is not operative. That it possesses no practical utility is fully proven. The scheme might be called one on hope or aspiration; but the device will operate in a laboratory at least, and we do not think the patent can be struck down as inoperative in the sense of the patent law. We find it true that no practical use has been made of this invention during the 13 years that have elapsed since specification filed. We continue to agree with the doctrine of Putnam, C. J., in Boston, etc., Co. v. Pennsylvania, etc., Co., 164 Fed. 557, 90 C. C. A. 84, as to the narrowness of interpretation to be awarded “paper patents”; but it is not necessary here to invoke that principle.
Appellant has presented objection to certain testimony admitted below. As our decision does not in the least rest upon that evidence, we do not discuss the matter; silence, however, is not to be regarded as decision in favor of admission.
Decree affirmed, with costs.