On July 31, 1790, the USPTO awarded its first patent to Samuel Hopkins for an improvement "in the making Pot Ash and Pearl Ash by a new Apparatus and Process." This patent was signed by, then president, George Washington.
The X-Patents (the first 10,000 issued between 1790 and 1836) were destroyed by a fire in 1836; less than 3,000 of those have been recovered and re-issued with numbers ending in "X" to distinguish them from those issued after the fire.
