Washington signs the nation's first patent, for a better way to make potash

Three months after Congress passed the Patent Act of 1790, the young federal government had yet to protect a single invention. On July 31, 1790, that changed when Samuel Hopkins, a Philadelphia potash manufacturer, received the first U.S. patent for an improved method of making potash and pearlash, ingredients used in soap, glass, and fertilizer. A three-man board of Thomas Jefferson, Henry Knox, and Edmund Randolph had judged the process "sufficiently useful and important," and President Washington signed the patent along with Jefferson and Randolph, though Knox did not sign. Hopkins paid roughly four or five dollars for fourteen years of exclusive rights…