delivered the opinion of the Court.
Thе courts below have held valid and infringed certain claims of three patents.
1
granted to Genzo Shimadzu, a citizen and resident of Japan. The earliest is for a method of forming a finely divided and, consequently, more chemically reactive, lead powder. The second is for a method or process of manufacturing a fine powder composed of lead suboxide and metallic lead and for the product-of
The bill was filed by the respondents as patentee and exclusive licensee. The answer denied that Shimadzu was the first inventor; asserted knowledge and use of the invention by the petitioner in the United States more than two years prior to the dates of the applications; and pleaded that earlier patents procured by Shimadzu in Japan avoided the United 1 States patents as the former were for the same inventions and each was granted more than a year prior to the filing of the corresponding application in this country. The case was tried, the District Court found the facts, stated its conclusions, and entered a decree for the respondents, 2 which the Circuit Court of Appeals affirmed. 3 The petitioner sought certiorari alleging that the case presents three questions, one which should be settled by this court and two which were decided below contrary to our аdjudications.
The questions are: In an infringement suit by the owner of a patent for an invention, made but not patented or published abroad, to restrain an innocent use, the inception of which antedates the application for patent, may the plaintiff prove that his actual date of invention was earlier than the commencement of the asserted infringing use? Is the delay of the patentee in this case in applying for patent a bar to relief for alleged infringement? Does commercial use of the patented process and , apparatus in the alleged infringer’s plant for more than two years prior to the application for patent preclude redress?
The inventions which are the basis of the patents were conceived by Shimadzu and reduced to practise in Japan not later than August 1919. He did not disclosе the inventions to anyone in the United States before he applied for United States patents. Application was presented for No. 1,584,149 on January 30, 1922; for No. 1,584,150 on July 14, 1923; and for No. 1,896,020 on April 27, 1926. The inventions were not patented or described in a printed publication in this or any foreign country prior to the filing of the applications. The petitioner, without knowledge of Shimadzu’s. inventions, began the use of a machine, which involved both the method and the apparatus of the patents, at Philadelphiа, Pennsylvania, early in 1921 and attained commercial production in June 1921. Over the objection of the petitioner the respondents were permitted by testimony, and by the introduction of contemporaneous drawings and note books, to carry the date of invention back to August 1919, and the courts below fixed that as the date of invention and reduction to prac-tise in Japan.
First.
The petitioner asserts that R. S. 4886, 4887, and 4923,
5
considered together, require one who has made
. The solution of the issue requires examination of two of the sections in the light of their development from earlier patent statutes.
R. S. 4886, as it stood when the patents were granted, 6 was:
“Any person who has invented or discovered any new and useful art, machine, manufacture, or composition of matter, or any new and useful improvements thereof, not known or used by others [in this country], [before his invention or discovery thereof], and not patented or described in any printed publication in this or any foreign country, before his invention or discovery thereof, [or more than two years prior to his application], and not in public use or on sale [in this country] for more than two years prior .to his application, unless the same is proved'to have been abandoned, may, upon payment of the fees required by law, and other due proceeding had, obtain a patent therefor.”
The legislative history of the section may be briefly outlined. The Patent Act of 1790
7
authorized the grant
The requirement of the Act of 1790 was that the discovery be “not before known or used.” The Act of 1793 amended this to read “not known or used before the application.”. The Act of 1800 altered the provision so that the petitioner had to swear that his invention had not “been known or used either in this or any foreign country.” The Act of 1836 changed the knowledge and use clause to read “not known or used by others before his or their discovery or invention thereof.”
Thesе successive alterations throw into relief the fact that the section makes the criterion of novelty the same whether the invention was conceived abroad or in this country. The test is whether the invention was “known or used by others in this country, before his invention or discovery thereof . . The elements which preclude patentability are a patent, or a description in a printed publication in this or any foreign country, which antedates the invention or discovery of the applicant.
The provisions of R. S. 4886 which affect the question are not modified by R. S. 4887, the purpose of which is to permit the filing of applications for the same invention in foreign countries and in the United States. It derives from § 25 of the Act of 1870. 13
The second paragraph of the section, which was added, by the Act of 1903 14 to comply with reciprocal agreements with foreign countries, gives the same force and еffect to the filing of an application in a foreign country as it would have if filed here on the date on which‘the. application fo** patent was first filed in the foreign country, provided-thai, the domestic.application is filed within twelve months 'of the foreign filing date. The last sentence of the paragraph, expressly preserves the bars of more than two- years’ prior patenting, description in a printed publication .before the filing of application in this country, and public use, more than two years before such filing. But the section does not contain any provision which precludes proof of facts respecting the actual date of invention in a foreign country to overcome the prior knowledge or use bar of § 4886.'
The petitioner also relies upon R. S. 4923, which provides that if the patentee, at the time of his application,
The section, on its face, is without application where the litigation is between the patentee of a foreign invention, or his assignee, and an alleged irifringer who defends only in virtue of prior knowledge or use not covered by a patent.
While this court has never been called upon to decide the precise question presented; the lower federal courts have refused to extend § 4923 to such a case. They have held that § 4886 does not limit the plaintiff to the date of application in this country but that he may prove the invention was in fact made at an earlier date, as could the owner of an invention made in the United States. 15
There is force in the petitioner’s argument that the distinction seems illogical. Thus, if a diligent domestic inventor applies, in good faith believing himself to be the first inventor, § 4923 assures him a patent and gives it priority, despite prior foreign use, even though that use is evidenced by a patent applied for after the invention made in this country. The foreign applicant or patentee
'We have no way of knowing whether the discrimination results from inadvertence or from some undisclosed legislative policy, but, in order to redress the disadvantage under which one in the petitioner’s situation suffers, we should have to read into the lаw words which plainly are missing. 16 We cannot thus rewrite the statute. 17 Moreover §§ 4886 and 4887 have repeatedly been amended and other portions of the patent act have been revised and amended from time to time since the decisions pointing out that § 4886 did not prevent the foreign inventor from carrying back his date of invention beyond the date of his application. Congress has not seen fit to amend the statute in this respect and we must assume that it has been satisfied with, and adopted, the construction given to its enactment by thе courts. 18
Second. A patent is not'validly issued if the invention “is proved to have been abandoned.” 19 Abandonment may be evidenced by the express and voluntary declaration of the inventor; 20 it may be inferred from negligence or unexplained delay in making application for patent; 21 it may be declared as a consequenсe of the inventor’s concealing his invention and delaying application for patent in an endeavor to extend the term of the patent protection beyond the period fixed by the statute. 22 In any case, the question whether the invention has been abandoned is one of fact. 23
Referring to a Japanese patent applied for November 27, 1920, and issued May 10,- 1922, the District Court found: “We are not concerned with the motives which prompted him ... . to confine it [the Japanese рatent] to the single step of mechanical removal of the dust from the drum, and to withhold the really essential steps of the invention for later patenting. It is sufficient to say that he had the right to do this if he chose.” Taken in connection with the court’s finding that Shimadzu’s inventions were conceived and reduced to practise in August 1919 this finding is said to convict him of intentional and inexcusable concealment. In the light of the record we are unable so to hold.
We think this is not a sufficient excuse for not pleading the defense. Alternative, and inconsistent defenses may be pleaded.
26
Certainly if the petitioner was surprised it could аt least have requested an opportunity to amend its answer. If the defense had been pleaded originally, or by amendment the respondents would have had an opportunity to meet it by proof and this they appear not to have been afforded.' We have a finding which seems not to have been addressed to this issue; and no findings as to the circumstances which led to the delay in filing applications. In the circumstances we think we are not justified in assigning to the findings below the force of a finding thаt Shimadzu, with intent, .concealed
Third. If a valid patent is to issue, the invention must not have been in public use in this country for more than two years prior to the filing of the application. 27 Such public use is an affirmative defense to be pleaded and proved. 28 The respondents insist that it was not pleaded in this case and that the findings respecting the defense, on which the petitioner relies, are unsupported by the evidence. We cannot agree with either position.
Although not required so to do, the respondents in their bill pleaded with respect to each of the patents that the invention had not been in public use for more than two years before application filed. The petitioner denied the allegation ,as to each patent and, in addition, alleged that it was successfully making and selling the product of the invention in its plant long before it ever learned of Shimadzu’s existence or his inventions, and further asserted that “the claims of said letters patent are invalid and void, because the subject matter thereof was, prior to the alleged invention thereof by Shimadzu, and for more than two years prior to his application dates, known to and used by the defendant at Philadelphia, Pennsylvania, .■ . .” Upon the trial, . employes of the petitioner described an early apparatus and process used in 1918 and 1919 and abandonеd in the latter year when experiments began towards employment of the apparatus and process the petitioner now uses. They testified' to the increasing perfection of the apparatus and process during the early months of 1921, and that commercial production was accomplished sometime between
The finding of the District Court appears under a heading in its opinion entitled “Alleged Prior Public Use.” As originally promulgated the finding fixed January 1921 as the date of commercial production. The respondents sought a rehearing and asked that the finding as to commercial production in January 1921 be revised. A rehearing was granted and the District Judge filed a memorandum amending his opinion. In this he said: “As to the second statement of fact, it may be said at once that it was never intended by the Court to make a finding of a prior public use (in the statutory sense of that term) by the defendant in January 1921.” After discussing the use of the apparatus in the early months of 1921, the court said: “It is therefore plain that there is no evidence of anything beyond an experimental use by the defendant earlier than about the middle of the year 1921. It is entirely possible that the word ‘January’ in
Both parties appealed to the Circuit Court of Appeals. That the respondents understood the force and effect of the finding as to prior use is evident from their assignments, one of which is that the District Court erred “in finding and adjudging that commercial production by the Hardinge mill with its forced draft involving the use of plaintiff’s patent began in June 1921.”
It remains to determine whether the' commercial use found is, in contemplation of law, a public use within the meaning of R. S. 4886. We hold that it is.
The earlier Aсts provided that the bar should consist in public use or sale “with the applicant’s consent or allowance prior to the application.” 29 The Act of 1839 30 altered the clause to read “no patent shall be héld to be invalid” except upon proof that “such ... prior use has been for more than two years prior to such application for a patent.” This court construed the later Act, which has been carried forward into the revised statutes, as rendering prior public use a bar whether the use was with or without the consent of the patentee. 31
Decisions turning on prior public use have been numerous both in this court and in other federal courts; and the definition of such use, formulated when the statute made only use by consent a bar, has been adopted in.
A mere experimental use is not the public use defined by the Act, 33 but a single use for profit, not purposely hidden, is such. 34 The ordinary use of a machine or the practise of a рrocess in a factory in the usual course of producing articles for commercial purposes is a public use. 35
In the present case the evidence is that the petitioner, since June 1921, has continuously employed the alleged infringing machine and process for the production of lead oxide powder used in the manufacture of plates for storage batteries which have been sold in quantity. There is no finding, and we think none would have been justified, to the effect that the maсhine, process, and product were not well known to the employes in the plant, or that efforts were made to conceal them from anyone who had a legitimate interest in understanding them. 36 This use, begun more than two years before Shimadzu applied for patents 1,584,150 and 1,896,020, invalidated the claims in suit.
Fourth.
The defense of prior public use is not made out against patent 1,584,149, for which application was
“Whether or not’149 is for the same process as U. S. patent ’150 is immaterial, so far as the question of validity of either is concerned. There is no double patenting involved. The two patents issued on the same day. They both expired on the same day. There can be no extension of thе monopoly and one is not prior art against the other.
“The fact that ’149 does not disclose the oxidizing function of the air or refer to the highly important element of the process having to do with the temperature control necessary to its successful operation might throw doubt upon its validity in view of the prior art. This is, of course, upon the assumption that it is not for the same invention as ’150. The whole matter however is rather academic since T49 is coincident in duration, with T50, and the defendant’s process infringes the somewhat more precise, if not narrower, claims of ’150.
“This patent is therefore held valid and infringed.”
The holding was .assigned as error in the Circuit Court of Appeals and is specified as error in the petition for certiorari.
The decree of the Circuit Court of Appeals must be reversed and "the cause remanded -to the District Court with directions to dismiss the bill as to Nos. 1,584,150 and 1,896,020, and to proceed, in the light of the dismissal as to those patents, to determine whether 1,584,149 is valid and infringed.
Reversed.
Notes
Patents. Date granted Claims
1,584,149. 5/11/1926 1 and 2
1,584,150. 5/11/1926 1-4, 6, 8-13
1,896,020. 1/31/1933 10 and 11
At the trial the respondents relied, to some extent, upon an adjudication in an interference proceeding between Shimadzu and Hall, an employe of the petitioner who in 1924 applied for a patent for a process of producing finely powdered mixed lead and lead oxide. See
Hall
v.
Shimadzu,
U. S. C. Tit. 35, §§ 31, 32, 72.
The section was amended by the Act of May 23, 1930, c. 312, § 1, 46 Stat. 376; to authorize the patenting of inventions of certain plants.
Act of April 10, 1790, §1,1 Stat. 109.
Act of Feb. 21, 1793, § 1, 1 Stat. 318.
Act of April 17, 1800, § 1, 2 Stat. 37.
Act of July 4, 1836, § 6, 5 Stat. 117, 119.
Act of July 8, 1870, c. 230, § 24, 16 Stat. 198, 201.
Act of March 3, 1897, c. 391, § 1, 29 Stat. 692.
§ 25, 16 Stat. 201.
Act of March 3, 1903, § 1, c. 1019, 32 Stat. 1226- -
Hanifen
v.
E. H. Godshalk Co., 78 F.
811;
Welsbach Light Co.
v.
American Incandescent Lamp Co.,
The petitioner would have us insert in § 4886, for the third time, the words “in this country” which Congress has twice inserted in the section by amendment. The petitioner’s argument requires us to read the section as if the phrase “in this country” appeared between the words “discovery thereof” and the words “and not patented.”
Dewey
v.
United States,
Sessions
v.
Romadka,
R. S. 4886, supra.
Kendall
v.
Winsor,
Consolidated Fruit-Jar Co. v. Wright,
Kendall
v.
Winsor, supra,
p. 328;
Macbeth-Evans Glass Co.
v.
General Electric Co.,
Pennock v. Dialogue. 2 Pet. 1, 16.
U. S. C. Tit. 35, § 69.
Crown Cork Co.
v.
Gutmann Co.,
Jones
v.
Sewall,
R. S. 4886, supra.
R. S. 4920,
supra; Klein
v.
Seattle,
Act of July 4^ 1836, § 7, 5 Stat. Í17, 119.
Act of March 3, 1839, § 7, 5 Stat. 353, 354.
Andrews v. Hovey,
Detroit Lubricator Co.
v.
Lunkenheimer,
Elizabeth
v.
Pavement Co.,
Consolidated Fruit-Jar Co.
v.
Wright, supra,
94;
Egbert
v.
Lippmann,
Manning
v.
Cape Ann Isinglass Co.,
Compare
Hall
v.
Macneale,
