The Bourdon tube is the key component of manometers, used for measuring pressure. It is made by flattening a metal tube and then forming it in a circular, spiral, or helix shape. When the pressure rises, the tube will uncoil. The resulting movement of the end of the tube is mechanically transmitted to a measuring element and thus to the pointer of the manometer. This type of tube is named after Eugène Bourdon (1808–1884) who submitted the patent in 1848.