Court Opinion

ID: 9419385
Source: CourtListenerOpinion
Date Created: 2023-08-02 22:49:12.595676+00
Date Added: 2024-06-11T16:42:07.424457
License: Public Domain

Mr. Justice Rutledge,
dissenting in part: •'
Until now law1 has united with almost universal repute2 in acknowledging Marconi, as the first to establish wireless telegraphy on a commercial basis. Before his, invention, now in. issue,3 ether-borne communication traveled some eighty miles. He lengthened the arc to 6,000. Whether or not this was “inventive” legally, it was a great and beneficial achievement.4 Today, forty years after the event, the Court’s decision reduces it to. an electrical mechanic’s application of mere skill in the art.
*65By present knowledge,: it would be no more. School boys and mechanics now could perform what Marconi did in 1900. But before then wizards had tried and failed. The search was at the pinnacle of. electrical knowledge. .There, seeking, among other's, were Tesla, Lodge and Stone, old hands and great ones.- With them was Marconi-,, still young as the company went5 obsessed with youth’s zeal for the hunt. .
At such an altitude, to work at all with success is to qualify-for genius, if that is important. And a short step forward gives- evidence of inventive power. . For at that height a merely slight advance comes through insight only a. first-rate mind can produce. ■. This is so, whether it;comes by years of hard work tracking down. the. sought secret or by intuition flashed from subconsciousness made fertile by long experience or shorter intensive concentration. At this level and in this company Marconi worked and won.
He won by the test of results. No one disputes this. His invention had immediate and vast success, where all that had been done before, including his own work, gave but narrowly limited utility. To make useful improvement at -this plane, by such a leap, itself shows high capacity. . And that is true,, although it was inherent in the situation that Marconi’s success should come by only a small margin of difference in conception. There was not roqm for. any great leap ,of thought, beyond what he and others had done, to bring to birth the practical and useful result. The most .eminent men of. the time were conscious of the. problem, were interested in it, had sought for years the exactly right arrangement, always approaching more nearly but never quite reaching the stage of prac*66tical success. The invention was, so to speak, hovering in the general climate of science, momentarily awaiting birth. But just the right releasing touch had not been found. Marconi added it.
When to altitude of the plane of conception and results so immediate and useful is added well-nigh unanimous contemporary judgment, one who long afterward would overturn the invention assumes a double burden. He undertakes to overcome what would offer strong resistance fresh in its original setting. He seeks also to overthrow the verdict of time. Long-range retroactive diagnosis, however competent the physician, becomes hazardous by progression as the passing years add distortions of the past and destroy its perspective. No light task is accepted therefore in undertaking to overthrow a verdict settled so long and so well, and especially one so foreign to the art of judges.
In lawyers' terms this means a burden of proof, not insurmountable, but inhospitable to implications and inferences which in less settled situations would be permissible to swing the balance of judgment against the claimed invention. That Marconi received patents elsewhere which, once established, have stood the test of time as well as of contemporary judgment, and secured his American patent only after years were required to convince our office he had found what so many others sought, but emphasizes the weight and clarity of proof required to overcome his claim.
Marconi received patents here, in England, and in France.6 The American patent was not issued perfunctorily. It came forth only after a long struggle had brought about reversal of the Patent Office's original and later rejections. The application was filed in November, *671900. In December it was rejected on Lodge,7 and an earlier patent to Marconi.8 It was amended and again rejected. Further amendments followed and operation of the system was explained. Again rejection took place, this time on Lodge, the earlier Marconi, Braun and other patents. After further proceedings, the claims were rejected on Tesla.9 A year elapsed, but in March, 1904, reconsideration was granted. Some claims then were rejected on Stone,10 others were amended, still others were cancelled, and finally on June 28,1904, the patent issued. French and British patents had been granted in 1900.
Litigation followed at once. Among Marconi’s American victories were the decisions cited above.11 Abroad the results were similar.12 Until 1935, when the Court of Claims held it invalid in this case, 81 Ct. Cl. 671, no court had found Marconi’s patent wanting in invention. It stood without adverse judicial decision for over thirty years. In the face of the burden this history creates, we turn to the references, chiefly Tesla, Lodge and Stone. The Court relies principally on Stone, but without deciding whether this was inventive.
It is important, in considering the references, to state the parties’ contentions concisely. The Government’s statement is that they differ over whether Marconi was first to conceive four-circuit “tuning” for transmission of sound by Hertzian waves. It says this was taught previously by Tesla, Lodge and Stone. Petitioner however says none of them taught what Marconi did. It contends that Marconi was the first to accomplish the kind of tun*68ing he achieved, and in effect urges this was patentahly different from other forms found earlier..
Specifically petitioner urges' that Tesla had nothing to do with either Hertzian waves or tuning, but in fact his transmitting and receiving wires could not be tuned.13 Lodge, it claims, disclosed a tuned antenna, for either transmitter or receiver or both, but the closed circuits associated with the antenna ones were not tuned. Finally it is said Stone does not describe tuning the antenna, but does show tuning of the associated closed circuit. And Marconi tuned both.
Petitioner does-not claim the general principles - of tuning. It admits they had long been familiar to physicists and that Lodge and others fully .understood them. But it asserts Lodge did not know what circuits should be tuned, to accomplish what Marconi achieved, and that, to secure this, “knowledge that tuning is possible is not enough — there is also required the. knowlédge of whether or- not to tune and how much.”
Likewise, petitioner does not deny that Stone knew and utilized the principles of tuning; but urges, with respect to the claim he applied them to all of the four circuits, that the only ones tuned, in his original application, were the closed circuits and therefore that the antenna circuits were not tuned; although it is not denied that the effects of tuning the closed circuits were reflected in the open ones by what Stone describes as “producing forced simple *69■harmonic electric vibrations of the same periodicity in an eleyated 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 baffling 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, conr versely, 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 apr proximately equal length. Such a series can be produced only by a circuit which conserves its energy- well, wh$t Marconi calls a persistent, oscillator. On.the other hand, for distant detection, the waves must be of substantial *70amplitude, 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 *71the 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 no 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*72ceiver” 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 oil .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 *73lie did. not do this or accomplish the same thing by any other device, such as a condenser, in the closed circuit. Andthe.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 hot 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 Marcpni 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 *74rejections on Lodge, Stone and other references, including all in issue here.
In the perspective of this decade, Marconi’s advance, in requiring “independent tuning,” that is, positive means of tuning located in both closed and open circuits, seems simple and obvious. It was simple. But, as is often true with great inventions, the simplest and therefore generally the best solution is not obvious at the time, though it becomes so immediately it is seen and stated. Looking back now at Edison’s light bulb one might think it absurd that that highly useful and beneficial idea had not been worked out long before, by anyone who knew the elementary laws of resistance in the field of electric conduction. But it would be shocking, notwithstanding the presently obvious character of what Edison did, for any court now to rule he made no invention.
The same thing applies to Marconi. Though what he did was simple, it was brilliant, and it brought big results. Admittedly the margin of difference between his conception and those of the references, especially Lodge and Stone, was small. It came down to this, that Lodge saw the need for and used means for performing the function which variable inductance achieves in the antenna or open circuit, Stone did the same thing in the closed circuit, but Marconi first did it in both. Slight as each of these steps may seem now, in departure from the others, it is as true as it was in 1911, when Mr. Justice Parker wrote, that the very fact men of the eminence of Lodge and Stone saw the necessity of taking the step for one circuit but not for the other is strong, if not conclusive, evidence that taking it for both circuits was not obvious. If this was so clearly indicated that anyone skilled in the art should have seen it, the unanswered and I think unanswerable question remains, why did not Lodge and Stone, both assiduously searching for the secret and both preeminent in the field, recognize the *75fact and make the application? The best evidence of the novelty of Marconi’s advance lies not in any judgment, scientific or lay, which could now be formed about it. It is rather in the careful, considered and substantially contemporaneous judgments, formed and rendered by both the patent tribunals and the courts when years had not distorted either the scientific or the legal perspective of the day when the invention was made. All of the references now used to invalidate Marconi were in issue, at one time or another, before these tribunals, though not all of them were presented to each. Their unanimous conclusion, backed by the facts which have been stated, is more persuasive than the most competent contrary opinion formed now about the matter could be.
It remains to give further attention concerning Stone. Admittedly his original application did not require tuning, in Marconi’s sense, of the antenna circuit, though it specified this for the closed one. He included variable inductance in the latter, but not in the former. His device therefore was, in this respect, exactly the converse of Lodge. But it is said his omission to specify the function (as distinguished from the apparatus which performed it) for the antenna circuit was not important, because the function was implicit in the specification and therefore supported his later amendment, filed more than a year following Marconi’s date, expressly specifying this feature for the open circuit.
Substantially the same answer may be made to this as Mr. Justice Parker made to the claim based on Lodge. Tuning both circuits, that is, including in each independent means for variable adjustment, was the very gist of Marconi’s invention. And it was what made possible the highly successful result. It seems strange that one who saw not only the problem, but the complete solution, should specify only half what was necessary to achieve it, neglecting to mention the other and equally important *76half as well, particularly when, as is claimed, the two weré so nearly identical except for location.. The very omission of explicit statement of so important and, it is claimed, so obvious a feature is evidence it was neither obvious nor conceived. And the force of the omission is magnified by the fact that its author, when he fully recognized its effect, found it necessary to make amendment to include it, after the feature was expressly and fully disclosed by another. Amendment under such circumstances, particularly with respect to a matter which goes to the root rather than an incident or a detail of the invention, is always to be regarded critically and, when the foundation claimed for it is implicit existence in the original application, as it must be, the clearest and most convincing evidence should be required when the effect is to give priority, by backward relation, over another, application intermediately filed.
Apart from the significance of omitting to express a'feature so important, I am unable to find convincing evidence the idea was implicit in Stone as he originally filed. His distinction between “natural” and “forced” oscillations seems to me to prove, in the light of his original disclosure, not that “tuning” of .the antenna circuit as Marconi required this was implicit; but rather that it was not present in that application at all. It is true he sought, as Marconi did, to make the antenna circuit at the transmitter the source of waves of but a single periodicity and the samé circuit at the receiver an absorber only of the waves so transmitted. .But the methods they used were not the same. ■ Stone’s method was to' provide “what are substantially, forced vibrations” in the.transmitter’s antenna circuit and, at the receiver, to impose “between'the vertical conductor [the antenna] . . . and the translating devices [in the closed .circuit] .[other] resonant circuits attuned to. the particular frequency of the electro-magnetic waves-*77which it is desired to have operate the translating devices.” (Emphasis added.) In short, he provided for “tuning,” as Marconi did, the transmitter’s closed circuit, the receiver’s closed circuit and the intermediate circuits which he interposed in the receiver between the open or antenna one and the closed one. But nowhere did he provide for or suggest “tuning,” as Marconi did and in his meaning, the antenna-circuit of the transmitter or the antenna circuit of the receiver. For resonance in the former- he depended upon the introduction, from the closed circuit, of “súbstantially forced electric vibrations” and for selectivity in the latter he used the intermediate tuned circuits. Stone and Marconi used the same means for creating persistent oscillation, namely, the use of the separate closed circuit; and in this both also developed single periodicity to the extent the variable inductance included there and there only could do so. But while both created persistent oscillation in the same way, Marconi went farther than Stone with single periodicity and secured enhancement of this by placing means for tuning in the antenna circuit, which admittedly Stone nowhere expressly required in his original application. And, since this is the gist-of the invention in issue and of the difference between the two, it will not do to dismiss this omission merely with the statement that there is nothing to suggest that.Stone “did not desire to have those circuits tuned.” Nor in my opinion do the passages in the specifications relied upon as “suggesting” the “independent” tuning of the.antenna circuits bear out this inference. . -
• When Stone, states that “the vertical -conductor at the transmitter station is made the source of . i . waves of but a single periodicity,” I find nothing to suggest that this is accomplished by specially tuning that circuit, or; in fact; anything more than that this circuit is a good conductor sending out the single period waves forced into it from the *78closed circuit. The same is true of the further statement that “the translating apparatus at the receiving station is caused to be selectively responsive to waves of but a single periodicity” (which tuning the intermediate and/or closed circuits there accomplishes), so that “the transmitting apparatus corresponds to a tuning fork sending but a single musical tone, and the receiving apparatus corresponds to an acoustic resonator capable of absorbing the energy of that single simple musical tone only.” (Emphasis added.) This means nothing more than that the transmitter, which includes the antenna, and the receiver, which also includes the antenna, send out and receive respectively a single period wave. It does not mean that the antenna, in either station, was tuned, in Marconi’s sense, nor does it suggest this.
The same is true of the other passages relied upon by the Court for suggestion. No word or hint can be found in them that Stone intended or contemplated independently tuning the antenna. They merely suggested, on the one hand, that when “the apparatus” at the receiving station is properly tuned to a particular transmitter, it will receive selectively messages from the latter and, further, that the operator may at will adjust “the apparatus at his command” so as to communicate with any one of several sending stations; on the other hand, that “any suitable device” may be used at the transmitter “to develop the simple harmonic force impressed upon” the antenna. “The apparatus,” as used in the statements concerning the adjustments at the receiving station, clearly means “the apparatus at his command,” that is, the whole of that station’s equipment, which contained in the intermediate and closed circuits, but not in the open one, the means for making the adjustments described. There is nothing whatever to suggest including a tuning device also in the open circuit. The statement concerning the use of “any *79suitable device” to "develop the simple harmonic force impressed upon the vertical wire” might be taken, in other context, possibly to suggest magnifying the impressed force by inserting a device for that purpose in the open circuit and therefore to come more closely than the other passages to suggesting Marconi’s idea. But such a construction would be wholly strained in the absence of any other reference or suggestion in the long application to such a purpose. Standing wholly alone as it does, it would be going far to base anticipation of Marconi’s idea upon this language only. The more reasonable and, in view of the total absence of suggestion elsewhere, the only tenable view is that the language was intended to say, not that Stone contemplated including any device for tuning-in the open circuit, but that he left to the mechanic or builder the choice of the various devices which might be used, according to preference, to create or “develop,” in the closed circuit, the force to be impressed upon the antenna.
Finally, Stone was no novice. He too was “a very expert person and one of the best men in the art.” National Electric Signalling Co. v. Telefunken Wireless Tel. Co., 209 F. 856, 864 (D. C.). He knew the difference between tuned and untuned circuits, how to describe them, and how to apply them when he wanted to do so. He used this knowledge when he specified including means for tuning in his closed circuit. He did not use it to specify similarly tuning the open one. The omission, in such circumstances, could hardly have been intentional. In my opinion he deliberately selected an aperiodic aerial, one to which the many receiving circuits his application contemplated could be adjusted and one which would carry to them, from his transmitter’s tuned periodicity and by its force alone, what it sent forward. In short, Stone deliberately selected an untuned antenna, a tuned *80closed circuit, and controlled the periodicity of both, not by independent means in each. making them mutually and reciprocally adjustable, but by impressing upon the untuned antenna. the forced periodicity of the , closed circuit. ■■ ,
It may be that by his method he attained results comparable, or nearly so, to those Marconi achieved. The record does not show that he did so prior to his amendment. If he did, that only goes to show he accomplished: in consequence what Marconi did, but by .a .different method. That, both had the same “broa,d purpose” of providing a high degree of tuning at both stations, and that both may have accomplished this object substantially, does not show that they did so in the same way or that Stone, by his different method, anticipated Marconi.
In my opinion therefore Stone's amendment was not supported by anything in his original application and should not have been allowed. As petitioner says, it added the new feature of tuning the antennat and in that respect resembled the amendment of a Fessenden application "to include- the tuning of the closed circuit.” National Electric Signalling Co. v. Telefunken Wireless Tel. Co., supra. The amendment here should receive the samp fate as befell the one there involved.
Stone’s-letters to Baker, quoted in the Court's opinion, show no more, than his original application disclosed. There is no hint or suggestion in them, of tuning the antenna circuits “independently” as Marconi did. And- the correspondence gives further proof he contemplated introducing the inductance coil (or a device equivalent in function) into the closed circuit, but expressed no idea of doing the same thing in the open one.
. In my opinion therefore the judgment -should be reversed,, in so far. as, it holds Marconi’s broad claims invalid.

 Marconi v. British Radio Tel. & Tel. Co., 27 T. L. R. 274; Marconi v. Helsby Wireless Tel. Co., 30 T. L. R. 688; Société Marconi v. Société Générale, etc., Civil Tribunal of the Seine, 3d Chamber, Dec. 24, 1912; Marconi Wireless Telegraph Co. v. National Electric Signalling Co., 213 F. 815 (D. C.); Marconi Wireless Telegraph Co. v. Kilbourne & Clark Mfg. Co., 265 F. 644 (C. C. A.), aff’g 239 F. 328 (D.C.).

 Cf., e. g., 14 Encyc. Britannica (14th ed.) 869.

 His earliest American patent, U. S. Patent No. 586,193, granted, on' July 13, 1897, later becoming Reissue Patent No. H',913, is not in suit’here. That, patent did not embrace many .of the crucial claims here involved and its product cannot compare in--commercial usefulness with that of the patent in suit.

 Courts closer to it chronologically than we are have characterized, it as a “conspicuous advance in wireless telegraphy”; “a real accomplishment”'and the ideas' involved in the patent were said-to “have proven of great value to the world,” to have brought' about “an entirely new and useful result,” “a new and very important-industrial result” and “a wonderful conquest.” “The Marco'ni patent standout as an unassailable monument until new. discoveries -are.made.”, Cf. the authorities cited in note 1, supra. "

 U. S. Patent No. 763,772; British Patent No. 7777 of 1900; French Patent No. 305,060 of Nov. 3, 1900.

 British patent to Lodge No. 29,505.

 Cf. note 3 supra.

 U. S. Patent to Tesla No. 649,621, May 15, 1900, division of 645,576, March 20,1900 (filed Sept. 2,1897).

 Cf. text infra.

 Cf. note 1 supra.

 Ibid.

 Tesla in fact did not use Hertzian waves. His idea was to make the ether a conductor for long distances by using extremely high voltage, 20,000,000 to 30,000,000 volts, and extremely high altitudes, 30,000 to 40,000 feet or more, to secure transmission from aerial to aerial. Balloons, with wires attached reaching to the ground, were his suggested aerials. His system was .really one for transmitting power for motors, lighting, etc.', to “any terrestrial distance,” though he incidentally mentions “intelligible messages.” As he did not use Hertzian waves, he had no such problem of selectivity as Marconi, Lodge, Stone and others were working on later.