The law was concise, defining the subject matter of a U.S. patent as "any useful art, manufacture, engine, machine, or device, or any improvement there on not before known or used.[4] The act was intended to grant patents only to the "useful Arts," which was usually the work of skilled workers and artisans, especially in the fields of engineering and manufacturing.The first patent was granted on July 31, 1790, to Samuel Hopkins for his invention of "Making Pot and Pearl Ashes."[4] Potash was used as an ingredient in several fields of manufacturing, such as making glass and soap, dying cloth, and producing both saltpeter and gunpowder.[8] Hopkins left behind a series of manuscripts describing the utility of his discovery of Potash, which is derived from a crude form of potassium carbonate and may be deemed as one of America's first chemicals to become widely used in industrial fields.The examination process required an unreasonable amount of time and soon became criticized by those in charge of administering it, the most vocal member being Thomas Jefferson.
