## Facts

- Esme E. Rosaire sued Baroid Sales Division of National Lead Company for infringing two method patents (U.S. Patent Nos. 2,192,525 and 2,324,085) concerning prospecting for oil or other hydrocarbons.
- The claimed method was based on the premise that hydrocarbons emanate gases that affect surrounding rock and could be detected through soil sampling.
- The method generally involved collecting multiple soil samples over an area or down a wellbore, treating each sample (e.g., grinding and heating in a closed vessel) to evolve entrained/absorbed hydrocarbons as gas, quantitatively measuring the evolved hydrocarbon gas, and correlating measurements with sample locations.
- Rosaire asserted the invention date as 1936 (with co-inventor Horvitz later assigning his interest to Rosaire).
- Rosaire alleged Baroid began using the method in 1947; Rosaire learned of this in 1949, sought a license, and then sued seeking injunctive relief and an accounting.
- Baroid defended primarily on invalidity, asserting the method was previously “known or used by others in this country” under 35 U.S.C. § 102(a), based on Gulf Oil work led by Abraham Teplitz in 1935–1936.
- The district court found Teplitz’s Gulf Oil work to be a successful and adequate field trial and a reduction to practice, performed openly in the ordinary course of Gulf Oil’s business, and entered judgment for Baroid, holding both patents invalid and not infringed.
- Rosaire argued the Gulf Oil activity was merely experimental and not sufficiently public because it was not patented, published, or broadly disseminated.

## Issues

1. Whether the asserted patent claims were invalid under 35 U.S.C. § 102(a) because the method was previously “known or used by others in this country” before Rosaire’s invention date.
2. Whether prior non-secret industrial field trials, not published or patented, can constitute “known or used” (and an effective reduction to practice) for § 102(a) purposes.
3. If the patents were valid, whether Baroid infringed the asserted claims.

## Decision

- The Fifth Circuit affirmed the judgment for Baroid.
- The court held both patents invalid because Teplitz and others at Gulf Oil had previously used the claimed method in the United States before Rosaire’s asserted invention date, satisfying § 102(a).
- The court rejected the argument that prior use must be published, patented, or widely publicized; open, non-secret use in the ordinary course of a company’s operations was sufficient.
- Given invalidity, the court treated infringement as non-dispositive and did not require detailed resolution of infringement to affirm the judgment.

## Legal Principles

- Under 35 U.S.C. § 102(a), a claimed invention is not patentable if, before the patentee’s invention, it was “known or used by others in this country.”
- Prior use need not be published or widely communicated to the public at large; non-secret use conducted openly in ordinary business operations can qualify as prior “known or used” activity.
- Field trials by another entity can constitute a reduction to practice when the evidence supports that the trials were successful and adequate, rather than merely preliminary experimentation.
- The presumption of validity may be weakened where significant prior art was not considered by the Patent Office during examination.

## Conclusion

The Fifth Circuit affirmed invalidity of the prospecting method patents because another company had previously reduced the same process to practice through open, non-secret field use in the ordinary course of business, which qualified as prior “known or used” activity under § 102(a) even without publication or a patent filing.


Rosaire v. Baroid Sales Div., Nat’l Lead Co., 218 F.2d 72 (5th Cir. 1955)