rent between the plate anode and the filament; that the strength of the current in the filament-to-plate circuit through the vacuum depends upon the degree of incandescence at the filament; and that the plate anode is preferably connected to the positive side of the current supply. The claims of the patent are for the combination of the filament, plate and interconnecting circuit, including the galvanometer. Claim 5, a typical claim, reads as follows:

The combination, with an incandescent electric lamp, of a circuit having one terminal in the vacuous space within the globe of said lamp, and the other connected with one side of the lamp-circuit, and electrically controlled or operated apparatus in said circuit, substantially as set forth.

The structural disclosed in Fleming's claims 1 and 37 thus differed in no material respect from that disclosed by Edison. Since Fleming's original claim 1 is merely for the structure, it reads directly on Edison's claim 5 and could not be taken as invention over it.

Fleming used this structure for a different purpose than Edison. Edison disclosed that his device operated to pass a current across the vacuous space within the tube between filament and plate. He used this current as a means of measuring the current passing through the filament circuit. Fleming, in his specifications, disclosed the use of his tube as a rectifier of alternating currents, and in claim 37 he claimed the use of that apparatus as a means of rectifying alternating currents of radio frequency. But in this use of the tube to convert alternating into direct currents there was no novelty for it had been disclosed by others and by Fleming himself long before Fleming's invention date. On January 9, 1890, ten years before Fleming filed his application. he stated in a paper read before the Royal Society of London:

It has been known for some time that if a platinum plate or wire is sealed through the glass bulb of an ordinary carbon filament incandescent lamp, this metallic plate being quite out of contact with the carbon conductor, a sensitive galvanometer connected between this insulated metal plate enclosed in the vacuum and the external positive electrode of the lamp indicates a current of some milliamperes passing through it when the lamp is set in action, but the same instrument when connected between the negative electrode of the lamp and the insulated metal plate indicates no sensible current. This phenomenon in carbon incandescence lamps was first observed by Mr. Edison, in 1884, and further examined by Mr. W. H. Preece, in 1885. Proceedings of the Roval Society of London, vol. 47, pp. 118-9.

Fleming's 1890 paper further pointed out that the vacuous space "possesses a curious unilateral conductivity"; that is, it permits current to "flow across vacuous space from the hot carbon [cathode] to the cooler metal plate [anode], but not in the reverse direction." Id. 122. He noted the ability of the tube to act as a rectifier of alternating current, saying:

When the lamp is actuated by an alternating current a continuous current is found flowing through a galvanometer, connected between the insulated plate and

either terminal of the lamp. The direction of current through the galvanometer is such as to show that negative electricity is flowing from the plate through the galvanometer to the lamp terminal. Id. 120.

Fleming's paper thus noted, contrary to the then popular conception, that it is negative electricity which flows from cathode to anode, but he emphasized that even this had been a part of general scientific knowledge, as follows:

The effect of heating the negative electrode in facilitating discharge through vacuous spaces had previously been described by W. Hittorf ("Annelen der Physik and Chemie," vol. 21, 1884, p. 90-139), and it is abundantly confirmed by the above experiments. We may say that a vacuous space bounded by two electrodes one incandescent and the other cold—possesses a unilateral conductivity for electric discharge when these electrodes are within a distance of the mean free path of projection of the molecules which the impressed electromotive force can detach and send off from the hot negative electrode.

This unilateral conductivity of vacuous spaces having unequally heated electrodes has been examined by MM. Elster and Geitel (see "Wiedemann's Annalen," vol. 38, 1889, p. 40), and also by Goldstein ("Wied. Ann.," vol. 24, 1885, p. 83), who in experiments of various kinds have demonstrated that when an electric discharge across a vacuous space takes place from a carbon conductor to another electrode, the discharge takes place at lower electromotive force when the carbon conductor is the negative electrode and is rendered incandescent. id. 125–6.

[12] Fleming's reference in this publication to the unilateral conductivity of the vacuous space between cathode and anode, and the consequent ability of the two to derive a continuous unidirectional current from an alterating current was a recognition that the Edison tube embodying the structure described could be used as a rectifier of alternating current. This knowledge, disclosed by publication more than two years before Fleming's application, was a bar to any claim for a patent for an invention embodying the published disclosure. R. S. §§ 4886, 4920; 35 U. S. C. § 31, 69. Wagner v. Meccano Ltd., 246 Fed. 603, 607; cf. Muncie Gear Co. v. Outboard Co., supra, 766.

[13] [14] It is unnecessary to decide whether Fleming's use of the Edison device for the purpose of rectifying high frequency Hertzian waves as distinguished from low frequency waves, involved invention over the prior art, or whether the court below rightly held that the devices used by the Government did not infringe the claims sued upon, for we are of the opinion that the court was right in holding that Fleming's patent was rendered invalid by an improper disclaimer. It is plain that Fleming's original claim 1, so far as applicable to use with low frequency alternating currents, involved nothing new, as Fleming himself must have known in view of his 1890 paper, and as he recognized by his disclaimer in 1915, made twenty-five years after his paper was published and ten years after his patent had been allowed. Its invalidity would defeat the entire patent unless the invalid portion had been claimed "through inadvertence, accident, or mistake, and without any fraudulent or deceptive intention," and was also dis

claimed without "unreasonable" neglect or delay. R. S. §§ 4917, 4922; 35 U. S. C. §§ 65, 71; Ensten v. Simon, Ascher & Co., 282 U. S. 445, 452, 404 O. G. 533; Altoona Theatres v. Tri-Ergon Corp., 294 U. S. 477, 493, 452 O. G. 705; Maytag v. Hurley Co., 307 U. S. 243, 504 O. G. 3.

[15] We need not stop to inquire whether, as the Government contends, the subject matter of the disclaimer was improper as in effect adding a new element to the claim. See Milcor Steel Co. v. Fuller Co., 316 U. S. 143, 147-8, 539 O. G. 959. For we think that the court below was correct in holding that the Fleming patent was invalid because Fleming's claim for "more than he had invented" was not inadvertent, and his delay in making the disclaimer was "unreasonable." Both of these are questions of fact, but since the court in its opinion plainly states its conclusions as to them, and those conclusions are supported by substantial evidence, its omission to make formal findings of fact is immaterial. Act of May 22, 1939, 53 Stat. 752, 28 U. S. C. § 288 (b); cf. American Propeller Co. v. United States, 300 U. S. 475, 479–80; Great Lakes Dredge & Dock Co. v. Huffman, No. 849, May 24, 1943.

[16] The purpose of the rule that a patent is invalid in its entirety if any part of it be invalid is the protection of the public from the threat of an invalid patent, and the purpose of the disclaimer statute is to enable the patentee to relieve himself from the consequences of making an invalid claim if he is able to show both that the invalid claim was inadvertent and that the disclaimer was made without unreasonable neglect or delay. Ensten v. Simon, Ascher & Co., supra. Here the patentee has sustained neither burden.

Fleming's paper of 1890 showed his own recognition that his claim of use of his patent for low frequency currents was anticipated by Edison and others. It taxes credulity to suppose, in the face of this publication, that Fleming's claim for use of the Edison tube with low frequency currents was made "through inadvertence, accident, or mistake," which is prerequisite to a lawful disclaimer. No explanation or excuse is forthcoming for his claim of invention of a device which he had so often demonstrated to be old in the art, and which he had specifically and consistently attributed to Edison. Nor is any explanation offered for the delay of the patentee the Marconi Company-in waiting ten years to disclaim the use of the device with low frequency currents and to restrict it to a use with high frequency Hertzian waves which Edison had plainly foreshadowed but not claimed. For ten years the Fleming patent was held out to the public as a monopoly of all its claimed features. That was too long in the absence of any explanation or excuse for the delay, and hence in this case was long enough to invalidate the patent. The conclusion of the Court of Claims not only has support in the evidence, but we can hardly see how on this record any other could have been reached.

The Marconi Company's contention that it nowhere appears that Fleming was not the first inventor of the use of the patented device to rectify high frequency alternating currents is irrelevant to the question of the sufficiency of the disclaimer. The disclaimer itself is an assertion that the claimed use of the invention with low frequencies was not the invention of the patentee, whose rights were derived wholly from Fleming. This improper claim for something not the invention of the patentee rendered the whole patent invalid unless saved by a timely disclaimer which was not made.

[17] The Marconi Company also asserts that, as it is suing as assignee of the patentee, it is unaffected by the provisions of the disclaimer statutes, which it construes as restricting to the "patentee" the consequences of unreasonable delay in making the disclaimer and as exempting the assignee from those consequences by the sentence "But no patentee shall be entitled to the benefits of this section if he has unreasonably neglected or delayed to enter a disclaimer." 35 U.S. C. 71. As the court below found, the Marconi Company was itself the patentee to whom the patent was issued on the assignment of Fleming's application in conformity to 35 U. S. C. § 44. The right given by § 71 to the patentee or his assignees to sue for infringement upon a proper disclaimer obviously does not relieve the patentee from the consequences of his failure to comply with the statute because he acquired his patent under an assignment of the application. Altoona Theatres v. Tri-Ergon Corp., supra; Maytag Co. v. Hurley Co., supra; France Mfg. Co. v. Jefferson Electric Co., 106 F. 2d 605, 610. Such a contention is not supported by the words of the statute and if allowed would permit the nullification of the disclaimer statute by the expedient of an assignment of the application. We need not consider whether one who has taken an assignment of a patent after its issuance would have any greater rights than his assignor in the event of the latter's undue delay in filing a disclaimer. Compare Apex Electrical Mfg. Co. v. Maytag Co., 122 F. 2d 182, 189.

The judgment in No. 373 is vacated and the cause remanded to the Court of Claims for further proceedings not inconsistent with this opinion.

The judgment in No. 369 is affirmed.

So ordered.

Mr. Justice MURPHY took no part in the consideration or decision of this case.

Mr. Justice FRANKFURTER, dissenting in part.

I regret to find myself unable to agree to the court's conclusion regarding the invalidity of the broad claims of Marconi's patent. Since broad considerations control the significance and assessment of the

details on which judgment in the circumstances of a case like this is based. I shall indicate the general direction of my views.

It is an old observation that the training of Anglo-American judges ill fits them to discharge the duties cast upon them by patent legislation. The scientific attainments of a Lord Moulton are perhaps unique in the annals of the English-speaking judiciary. However, so long as the Congress, for the purposes of patentability, makes the determination of originality a judicial function, judges must overcome their scientific incompetence as best they can. But consciousness of their limitations should make them vigilant against importing their own notions of the nature of the creative process into Congressional legislation, whereby Congress "to promote the Progress of Science and useful Arts" has secured "for limited Times to *** Inventors the exclusive Right to their *** Discoveries." Above all, judges must avoid the subtle temptation of taking scientific phenomena out of their contemporaneous setting and reading them with a retrospective eye.

The discoveries of science are the discoveries of the laws of nature, and like nature do not go by leaps. Even Newton and Einstein, Harvey and Darwin, built on the past and on their predecessors. Seldom indeed has a great discoverer or inventor wandered lonely as a cloud. Great inventions have always been parts of an evolution, the culmination at a particular moment of an antecedent process. So true is this that the history of thought records striking coincidental discoveries— showing that the new insight first declared to the world by a particular individual was "in the air" and ripe for discovery and disclosure.

The real question is how significant a jump is the new disclosure from the old knowledge. Reconstruction by hindsight, making obvi

1 "Considering the exclusive right to invention as given not of natural right, but for the benefit of society, I know well the difficulty of drawing a line between the things which are worth to the public the embarrassment of an exclusive patent, and those which are not. As a member of the patent board for several years, while the law authorized a board to grant or refuse patents, I saw with what slow progress a system of general rules could be matured. Instead of refusing a patent in the first instance, as the board was authorized to do, the patent now issues of course, subject to be declared void on such principles as should be established by the courts of law. This business, however, is but little analogous to their course of reading, since we might in vain turn over all the lubberly volumes of the law to find a single ray which would lighten the path of the mechanic or the mathematician. It is more within the information of a board of academical professors, and a previous refusal of patent would better guard our citizens against harassment my law suits. But England bad given it to her judges, and the usual predominancy of her examples carried it to ours." Thomas Jefferson to Mr. Isaac M'Pherson, August 13, 1813, Works of Thomas Jefferson, Wash. Ed., vol. VI, pp. 181-82.

"I cannot stop without calling attention to the extraordinary condition of the law which makes it possible for a man without any knowledge of even the rudiments of chemistry to pass upon such questions as these. The inordinate expense of time is the least of the resulting evils, for only a trained chemist is really capable of passing upon such facts, e. g., in this case the chemical character of Von Furth's so-called 'zinc compound,' or the presence of inactive organic substances. How long we shall continue to blunder along without the aid of unpartisan and authoritative scientific assistance in the administration of justice, no one knows; but all fair persons not conventionalized by provincial legal habits of mind ought, I should think, unite to effect some such advance." Judge Learned Hand in Parke Davis & Co. v. Mulford Co., 189 Fed. 95, 115 (1911).

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