CASES ADJUDGED IN THE SUPREME COURT OF THE UNITED STATES AT OCTOBER TERM, 1934. RADIO CORPORATION OF AMERICA ET AL. v. RADIO ENGINEERING LABORATORIES, INC. CERTIORARI TO THE CIRCUIT COURT OF APPEALS FOR THE SECOND CIRCUIT. No. 619 (October Term, 1933). Argued May 2, 3, 1934.-Decided May 21, 1934. Petition for rehearing denied, and opinion amended, Oct. 8, 1934. 1. Where this Court has affirmed a decree upholding a patent in a suit presenting the issue of priority between those who were rival claimants in the patent office proceedings, upon the ground that the unsuccessful party had failed to establish his superior right by thoroughly convincing evidence, the decree is not conclusive upon a stranger to that record in a subsequent suit against him for infringement, but it is persuasive as a precedent where the issue in the second suit and the evidence concerning it are the same as before. P. 7. 66 2. Patents Nos. 1,507,016 and 1,507,017, to Lee De Forest, Sept. 2, 1924, for a feed back" and an audion " oscillator," sustained upon the evidence as to priority of discovery. P. 10. 3. A patentee is entitled not only to the uses for his invention that were apparent when it was made, but also to other uses then dimly apprehended but realized later. P. 14. 66 F. (2d) 768, reversed; 1 F. Supp. 65 (D. C.), affirmed. CERTIORARI, 290 U. S. 624, to review the reversal of a decree of the District Court sustaining patents upon the ground of priority, in a suit brought by their assignees 89995-35- -1 1 against an infringer. Because of the pendency of a petition for rehearing, the opinion, delivered at the last Term, was not published in vol. 292. It is now printed with the amendments that were directed by the order of October 8, 1934, denying the rehearing. See post, p. 522. Messrs. Thomas G. Haight and Samuel E. Darby, Jr., with whom Messrs. James R. Sheffield, William R. Ballard, and Abel E. Blackmar, Jr., were on the brief, for petitioners. Mr. William H. Davis for respondent. MR. JUSTICE CARDOZO delivered the opinion of the Court. The petitioners, assignees of two patents, numbers 1,507,016 and 1,507,017, granted to Lee De Forest on September 2, 1924, have sued to restrain an infringement and for other relief. The respondent, defendant in the trial court, admits the infringement if the patents are valid, but maintains that they are void in that they were issued to a patentee who was not the first inventor. Long before this suit the rival claimants to the invention, Armstrong and De Forest, had fought out between themselves the legal battle now renewed. The outcome of their contest was a decree whereby priority of invention was found in accordance with the patents now assailed by the respondent, a decree binding on the claimants and their several assignees. For the purpose of any controversy between Armstrong and De Forest the validity of the patents must be accepted as a datum. Even for the purpose of a controversy with strangers there is a presumption of validity, a presumption not to be overthrown except by clear and cogent evidence. The question is whether the respondent has sustained that heavy burden, At the outset there were four claimants to priority of title. All four, acting independently, had made the same or nearly the same discovery at times not widely separate. The prize of an exclusive patent falls to the one who had the fortune to be first. Du Bois v. Kirk, 158 U.S. 58, 66; Evans v. Eaton, 3 Wheat. 454. The others gain nothing for all their toil and talents. Of the four claimants Langmuir filed an application for a patent on October 29, 1913, claiming August 1, 1913, as the date of his invention. Armstrong filed an application on October 29, 1913, and a second one on December 18, 1913, fixing the date of his invention as the fall of 1912 or the beginning of 1913. As early as October 6, 1914, he received a patent covering the subject matter of his first application (patent No. 1,113,149), but not the subject matter of his second. Meissner filed an application on March 16, 1914, fixing the date of his invention as April 9, 1913. De Forest filed an application on March 20, 1914, and another on September 23, 1915, fixing as the date of his invention August 6, 1912, the earliest date of all, which would make him the first inventor if the claim could be made good. Interferences were declared by the Patent Office as the result of these conflicting applications. One involved the applications of De Forest and Langmuir; another the applications of De Forest, Langmuir and Meissner; a third the applications by De Forest, Langmuir and Meissner and also the second one of Armstrong's, the only one of his then pending. While these interferences were still undecided, Armstrong and his assignee brought suit for the infringement of patent No. 1,113,149, which had been issued to him in October, 1914, the defendant in that suit being the De Forest Radio Telephone & Telegraph Company. The District Court (per Mayer, J.) fixed the date of Armstrong's discovery as January 31, 1913, rejected De Forest's claim to discovery on August 6, 1912, and gave |