Response or Comment
An unusually obvious piece of judicial legislation, of practical importance to the manufacturing world, was promulgated in the case of Macbeth-Evans Glass Co. v. General Electric Co., 246 Fed. 695. The facts were that in 1903 Macbeth had invented a process for making glass. Since that time the plaintiff company, of which Macbeth was president, had been using that process. This use had, however, been "secret". In 1910 an employee of the plaintiff revealed the process to the Jefferson Glass Co., which at once began to use it, but on application of the Macbeth Co. the state court enjoined the Jefferson Co. from further use of the process and from disclosing it to others. Macbeth-Evans Glass Co. v. Schnelbach, 239 Pa. 76. The secret of the process was not revealed by the proceedings in this suit. It does not appear how the General Electric Co. acquired knowledge of the process; whether it did learn the secret of the Macbeth process, or evolved a similar process by its own independent efforts. Macbeth applied for a patent in 1913 and when it was issued the Macbeth Co., as his assignee, brought this suit for infringement. The General Electric Co. defended on the ground that Macbeth had lost his right to a patent, by his failure to apply for one reasonably soon after he had perfected his invention, and that, consequently, the patent issued to him was void.
Waite, John B. "Patent Law: Secret Use as Affecting Right to a Patent." Mich. L. Rev. 17, no. 6 (1919): 499-501.