In 1849 Mr. Lincoln was issued a patent for his invention from the United States Patent & Trademark Office (USPTO). This is the first and only United States Patent issued to an inventor who would later become President. After a brief demonstration, where the Washington Monument now stands, the ground work was laid in to supply the Union army with 20,000 units of Mr. Spencer's prototype. There were 3 documents on file for this patent.The drawing specification sheet of the patent has been reproduced from original USPTO documents and printed onto parchment paper. This print is sized and ready to install into an 8" x 10" frame. The additionalsheets included are printed on 5.50" x 8.50" parchment paper. These accompanying documents describe the scope of this invention in formal terms. The following is an actual excerpt from the patent…

       " Be it known that I, Abraham Lincoln, of Springfield, in the County of Sangamon, in the State of Illinois, have invented a new and improved manner of combining adjustable buoyant air chambers with a steamboat or other vessel for the purpose of enabling their draught of water to be readily lessened to enable them to pass over bars, or through shallow water, without discharging their cargoes; and I do hereby declarethe following to be a full, clear, and exact description thereof, reference being had to the accompanying drawings making a part of this specification."…