Nicolas-Joseph Cugnot (February 26, 1725 - October 2, 1804) was a French inventor. He built the first working self-propelled mechanical vehicle. He was one of the first to employ successfully a device for converting the reciprocating motion of a steam piston into rotary motion by means of a ratchet arrangement. A small version of his three-wheeled fardier ? vapeur (steam dray) ran in 1769. The vehicle had two wheels at the rear and one in the front that supported the steam boiler and driving mechanism. The power unit was articulated to the trailer and steered from there by means of a double handle arrangement. It, reportedly, seated four passengers and moved at a speed of 2.25 miles per hour. The vehicle was unstable due to poor weight distribution. After running a small number of trials the project was abandoned and the French Army's experiment with mechanical vehicles came to an end.