## Facts

- George A. Macbeth developed a formula and process for making illumination glass by no later than 1903.
- Macbeth-Evans Glass Company (assignee) used the process internally as a trade secret for roughly a decade before seeking patent protection.
- Throughout that period, Macbeth-Evans sold the resulting glass products in large quantities as regular commercial goods in the United States, while keeping the process secret.
- In 1910, a trusted employee left Macbeth-Evans and wrongfully disclosed the secret process to Jefferson Glass Company, which then used it in secret and sold similar products commercially before the patent application was filed.
- Macbeth-Evans sued in Pennsylvania state court to protect the trade secret and obtained relief without publicly disclosing the process.
- Macbeth applied for a patent on May 9, 1913; a reissue patent later issued in 1914 and was asserted against General Electric for infringement.
- In the infringement suit, General Electric raised a distinct defense that the prolonged secret, commercial exploitation before filing constituted abandonment/forfeiture of the patent right; relevant facts were admitted for purposes of resolving that defense.
- The district court accepted the defense and entered judgment for General Electric; Macbeth-Evans appealed.

## Issues

1. Whether an inventor’s prolonged, non-experimental secret use of a process, coupled with commercial sale of products made by it, before filing a patent application constitutes abandonment or forfeiture of the right to a patent.
2. Whether such abandonment renders the later-issued patent invalid and unenforceable in an infringement action.

## Decision

- The Sixth Circuit affirmed judgment for General Electric.
- The court held that Macbeth’s extended secret commercial use of the process before filing was inconsistent with the patent system and amounted to abandonment/forfeiture of the right to patent protection.
- Because the patent was invalid on that ground, Macbeth-Evans could not enforce it against General Electric, regardless of how General Electric learned or developed the process.

## Legal Principles

- An inventor may forfeit the right to patent protection by unreasonably delaying a patent application while commercially exploiting the invention.
- Secret use can bar patent rights when it is a deliberate, continuous, non-experimental commercial practice that yields marketplace benefit before filing.
- Trade-secret enforcement against misappropriators does not preserve or revive patent rights lost through prior secret commercial exploitation and delay.
- Once abandonment/forfeiture invalidates the patent, infringement liability cannot be imposed based on that patent, even if the accused user did not independently invent the process.

## Conclusion

The court treated prolonged secret commercial exploitation of an invention, followed by a late patent application, as an election inconsistent with the patent bargain of prompt disclosure for limited exclusivity; that conduct forfeited the patent right and rendered the asserted reissue patent invalid.


Macbeth-Evans Glass Co. v. Gen. Elec. Co., 246 F. 695 (6th Cir. 1917)