Samuel Hopkins received the first U.S. patent issued under the Constitution, granted in 1790 for an improved potash-making process. The patent began the federal patent system created by the new government.
President George Washington signed Hopkins’s patent on July 31, 1790. The invention concerned an improvement in the process of making potash, a potassium compound used in products such as soap, glass, and fertilizer. Attorney General Edmund Randolph, Secretary of State Thomas Jefferson, and Secretary of War Henry Knox examined early patent applications under the original system.
The 1790 patent law required the secretary of state, secretary of war, and attorney general to determine whether an invention was sufficiently useful and important to merit protection. This differed from the later patent system, which relied on a specialized Patent Office and more formal examination procedures.
Only three patents were issued under the first federal patent law before Congress replaced it in 1793 with a registration-based system. Hopkins’s patent is therefore an especially precise milestone: it was the first patent granted under the constitutional federal government, not the first invention ever patented in North America.