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RUTLEDGE, J., dissenting.
harmonic electric vibrations of the same periodicity in an elevated conductor."
The Stone amendments of 1902, made more than a year after Marconi's filing date, admittedly disclose tuning of both the closed and the open circuits, and were made for the purpose of stating expressly the latter effect, claimed to be implicit in the original application. Petitioner denies this was implicit and argues, in effect, that what Stone originally meant by “producing forced ... vibrations" was creating the desired effects in the antenna by force, not by tuning; and therefore that the two methods were patentably different.
It seems clear that the parties use the word “tuning” to mean different things and the ambiguity, if there is one, must be resolved before the crucial questions can be stated with meaning. It will aid, in deciding whether there is ambiguity or only confusion, to consider the term and the possible conceptions it may convey in the light of the problems Marconi and Stone, as well as other references, were seeking to solve.
Marconi had in mind first a specific difficulty, as did the principal references. It arose from what, to the time of his invention, had been a bafiling problem in the art. Shortly and simply, it was that an electrical circuit which is a good conserver of energy is a bad radiator and, conversely, a good radiator is a bad conserver of energy. Effective use of Hertzian waves over long distances required both effects. To state the matter differently, Lodge had explained in 1894 the difficulties of fully utilizing the principle of sympathetic resonance in detecting ether waves. To secure this, it was necessary, on the one hand, to discharge a long series of waves of equal or approximately equal length. Such a series can be produced only by a circuit which conserves its energy well, what Marconi calls a persistent oscillator. On the other hand, for distant detection, the waves must be of substantial RUTLEDGE, J., dissenting.
320 U.S. amplitude, and only a circuit which loses its energy rapidly can transmit such waves with maximum efficiency. Obviously in a single circuit the two desired effects tend to cancel each other, and therefore to limit the distance of detection. Similar difficulty characterized the receiver, for a good radiator is a good absorber, and that very quality disables it to store up and hold the effect of a train of waves, until enough is accumulated to break down the coherer, as detection requires.
Since the difficulty was inherent in a single circuit, whether at one end or the other, Marconi used two in both transmitter and receiver, four in all. In each station he used one circuit to obtain one of the necessary advantages and the other circuit to secure the other advantage. The antenna (or open) circuits he made "good radiators" (or absorbers). The closed circuits he constructed as "good conservers.” By coupling the two at each end loosely he secured from their combination the dual advantages he sought. At the transmitter, the closed circuit, by virtue of its capacity for conserving energy, gave persistent oscillation, which passed substantially undiminished through the coupling transformer to the "good radiator" open circuit and from it was discharged with little loss of energy into the ether. Thence it was picked up by the "good absorber" open circuit and passed, without serious loss of energy, through the coupling transformer, into the closed "good conserving" circuit, where it accumulated to break the coherer and give detection.
Moreover, and for present purposes this is the important thing, Marconi brought the closed and open circuits into almost complete harmony by placing variable inductance in each. Through this the periodicity of the open circuit was adjusted automatically to that of the closed one; and, since the circuits of the receiving station were similarly adjustable, the maximum resonance was secured throughout the system. Marconi thus not only solved RUTLEDGE, J., dissenting.
the dilemma of a single circuit arrangement; he attained the maximum of resonance and selectivity by providing in each circuit independent means of tuning.
In 1911 this solution was held inventive, as against Lodge, Marconi's prior patents, Braun and other references, in Marconi v. British Radio Tel. & Tel.Co., 27 T. L. R. 274. Mr. Justice Parker carefully reviewed the prior art, stated the problem, Marconi's solution, and in disposing of Braun's specification concluded it “did not contain even the remotest suggestion of the problem ..., much less any suggestion bearing on its solution. ..." As to Lodge, Mr. Justice Parker observed, referring first to Marconi:
“... It is important to notice that in the receiver the mere introduction of two circuits instead of one was Do novelty. A figure in Lodge's 1897 patent shows the open circuit of his receiving aerial linked through a transformer with a closed circuit containing the coherer, his idea being, as he states, to leave his receiving aerial freer to vibrate electrically without disturbance from attached wires. This secondary circuit, as shown, is not tuned to, nor can it be tuned to, the circuit of the aerial. This, in my opinion, is exceedingly strong evidence that Marconi's 1900 invention was not so obvious as to deprive it of subject matter. In the literature quoted there is no trace of the idea underlying Mr. Marconi's invention, nor, so far as I can see, a single suggestion from which a competent engineer could arrive at this idea.” (Emphasis added.)
It was therefore clearly Mr. Justice Parker's view, in his closer perspective to the origin of the invention and the references he considered, that in none of them, and particularly not in Lodge or Braun, was there anticipation of Marconi's solution.
He did not mean that the references did not apply "the principle of resonance as between transmitter and re
ceiver" or utilize “the principle of sympathetic resonance for the purpose of detection of ether waves." For he expressly attributed to Lodge, in his 1894 lectures, explanation "with great exactness [of] the various difficulties attending the full utilization” of that principle. And in referring to Marconi's first patent, of 1896, the opinion states that Marconi "for what it was worth ... tuned the two circuits [i. e., the sending and receiving ones] together as Hertz had done." (Emphasis added.)
From these and other statements in the opinion it is obvious that Mr. Justice Parker found Marconi's invention in something more than merely the application of the "principle of resonance," or "sympathetic resonance," or its use to "tune” together the transmitting and receiving circuits. For Marconi in his own prior inventions, Lodge and the other references, in fact all who had constructed any system using Hertzian waves capable of transmitting and detecting sound, necessarily had made use, in some manner and to some extent, of "the principle of resonance" or "sympathetic resonance.” That principle is inherent in the idea of wireless communication by Hertzian waves. So that, necessarily, all the prior conceptions included the idea that common periodicity must appear in all of the circuits employed.
Nor did Mr. Justice Parker's opinion find the inventive feature in the use of two circuits instead of one, at any rate in the receiver. For he expressly notes this in Lodge. But he points out that Lodge added the separate circuit “to leave his receiving aerial freer to vibrate electrically without disturbance from attached wires.” And he goes on to note that this secondary (or closed) circuit not only was not, but could not be, "tuned” to the aerial circuit. And this he finds "exceedingly strong evidence" that "Marconi's 1900 invention was not so obvious as to deprive it of subject matter." Lodge had "tuned" the antenna circuit, by placing in it a variable inductance. But
he did not do this or accomplish the same thing by any other device, such as a condenser, in the closed circuit. And the fact that so eminent a scientist, the one who in fact posed the problem and its difficulties, did not see the need for extending this "independent tuning” (to use Marconi's phrase) to the closed circuit, so as to bring it thus in tune with the open one, was enough to convince Mr. Justice Parker, and I think rightly, that what Marconi did over Lodge was not so obvious as to be without substance.
In short, Mr. Justice Parker found the gist of Marconi's invention, not in mere application of the general principle or principles of resonance to a four-circuit system, or in the use of four circuits or the substitution of two for one in each or either station; but, as petitioner now contends, in recognition of the principle that, whether in the transmitter or the receiver, attainment of the maximum resonance required that means for tuning the closed to the open circuit be inserted in both. That recognized, the method of accomplishing the adjustment was obvious, and different methods, as by using variable inductance or a condenser, were available. As petitioner's reply brief states the matter, "The Marconi invention was not the use of a variable inductance, nor indeed any other specific way of tuning an antenna-before Marconi it was known that electrical circuits could be tuned or not tuned, by inductance coils or condensers. His broad invention was the combination of a tuned antenna circuit and a tuned closed circuit." (Emphasis added.) And it is only in this view that the action of the Patent Office in finally awarding the patent to Marconi can be explained or sustained, for it allowed claims both limited to and not specifying variable inductance. That feature was essential for both circuits in principle, but not in the particular method by which Marconi accomplished it. And it was recognition of this which eventually induced allowance of the claims, notwithstanding the previous