A pitot tube (/ˈpiːtoʊ/ PEE-toh; also pitot probe) measures fluid flow velocity. It was invented by French engineer Henri Pitot and published in 1732,[1] and modified to its modern form in 1858 by Henry Darcy.[2] It is widely used to determine the airspeed of aircraft;[3] the water speed of boats; and the flow velocity of liquids, air, and gases in industry.