## Facts

- Samuel H. Barnes invented an “improvement in corset springs,” using two or more metallic plates fastened at the center and connected near the ends to slide lengthwise for flexibility and strength.
- Around 1855, Barnes gave Frances Barnes (later Frances Egbert) a pair of the corset steels to use in the ordinary way, without conditions or any secrecy requirement.
- Frances wore the steels in her corsets for years and transferred them between corsets as garments wore out.
- In 1858, Barnes gave her another pair, which she likewise used over a long period.
- In 1863, Barnes demonstrated the corset steels to a friend by having his wife remove the steels from her corset so Barnes could explain their construction and operation.
- Barnes applied for a patent in March 1866; the patent issued in July 1866. After Barnes’s death, Frances (as executrix/assignee) obtained a reissue in 1873.
- Frances sued Philip Lippmann and August Seligmann in equity for infringement of the reissued patent’s second claim.
- The circuit court dismissed the suit, holding the patent invalid because the invention had been in public use for more than two years before the 1866 application.

## Issues

1. Whether an inventor’s unrestricted gift of a completed invention to another for ordinary use constitutes “public use” when that use occurs more than two years before the patent application.
2. Whether “public use” can exist where only one person uses a single embodiment and the invention is not visible during normal use.
3. Whether the use at issue was experimental or otherwise exempt from the statutory public-use bar.

## Decision

- The Supreme Court affirmed the dismissal and held the patent (and reissue) invalid due to public use for more than two years before the application.
- The Court ruled that an unrestricted gift or transfer for ordinary use, without secrecy limitations, is a public use within the meaning of the statute.
- The Court rejected arguments that public use requires multiple users, multiple articles, or visibility to observers.
- The Court found no experimental purpose; the corset steels were a completed article put to practical use with the inventor’s consent.

## Legal Principles

- A patent is barred when, with the inventor’s consent, the invention is in public use for more than the statutory period before filing.
- Use may be “public” even if only one person uses one embodiment of the invention.
- Visibility to the public is not required; an invention capable of ordinary use while concealed may still be in public use.
- An unrestricted gift or sale to another for ordinary use, without any limitation, restriction, or secrecy obligation, places the invention in public use.
- Experimental or testing use may avoid the bar, but ordinary practical use of a completed invention does not qualify as experimental absent evidence of testing intent and controls.

## Conclusion

The Court held that Barnes’s unrestricted transfer of corset steels to be worn in ordinary use, followed by long-term use more than two years before filing, constituted public use even though the device was hidden and used by a single person, rendering the patent invalid under the statutory bar.


Egbert v. Lippmann, 104 U.S. 333 (1881)