The first patent was for a process of making potash, an ingredient used in fertilizer. https://www.uspto.gov/about-us/news-updates/first-us-patent-issued-today

The first patent was for a process of making potash, an ingredient used in fertilizer. https://www.uspto.gov/about-us/news-updates/first-us-patent-issued-today-1790 https://www.uspto.gov/about-us/news-updates/first-us-patent-...