## Facts

- Edwin L. Brady held an 1867 patent for an “improved dredge boat for excavating rivers.”
- The claimed dredge boat combined known components: stern propellers for propulsion and steering, a bow-mounted “mud fan” to stir bottom material into the current, and watertight compartments with pumps to sink and raise the vessel while keeping an even keel.
- The patent claims focused on (1) a boat with watertight compartments arranged to maintain an even keel as they fill, enabling dredging without extra adjusting devices, and (2) the combination of the mud fan, watertight compartments arranged for even-keel settling, and a pump to exhaust the compartments.
- Atlantic Works, a Massachusetts shipbuilder, built and used a dredge boat that Brady alleged incorporated his patented combination.
- Brady sued in equity seeking an injunction and an accounting of profits; the trial court sustained the patent and granted relief.
- Atlantic Works appealed to the U.S. Supreme Court.

## Issues

1. Whether Brady’s claimed combination reflected patentable “invention” and novelty, or merely an expected arrangement of known elements within ordinary mechanical skill.
2. Whether the dates of other patents could be used as evidence of invention priority when the patented subject matter was put into actual use, even if those patents were not pleaded as a formal defense.
3. Whether a patent is void where the patentee obtained from another a full and accurate description of the improvement and attempted to patent it as his own.

## Decision

- The Supreme Court reversed the decree for Brady and held the patent invalid for want of novelty and invention.
- The Court stated that patent law rewards substantial advances, not minor devices or predictable variations that would occur to skilled mechanics in ordinary progress.
- The Court held that, where an invention covered by another patent has been put into actual use, that patent’s date may be admitted as evidence of the invention’s date in a priority dispute even if not pleaded in the answer.
- The Court held that a person who receives from another a full and accurate description of a useful improvement cannot appropriate it by taking out a patent; such a patent is void.

## Legal Principles

- Patents are reserved for substantial discoveries or inventions that represent a real step forward in the useful arts; exclusive rights should not issue for trivial or predictable modifications of known technology.
- A combination of known elements is not patentable absent a sufficient inventive contribution beyond ordinary mechanical skill and expected results.
- In priority disputes, the date of a patent covering an invention that was later put into actual use may be used as evidence of the invention’s date even if the patent is not pleaded as a formal defense.
- Patents obtained through derivation—claiming as one’s own an improvement fully described by another—are invalid because the applicant is not the true inventor.

## Conclusion

The Supreme Court invalidated Brady’s dredge-boat patent because it claimed an expected combination of existing parts rather than an inventive advance, and it reaffirmed that patent rights cannot rest on trivial variations or on appropriating another’s described improvement.


Atlantic Works v. Brady, 107 U.S. 192 (1883)