The Inventor of the Sankey Diagram: Captain Henry R. Sankey

Captain Riall Sankey (1853 - 1925). Source: Institution of Mechanical Engineers


In the late 19th century, countless engineers from developing industrial countries were trying to use scientific methods to improve the functions of steam machines and to optimize their various uses. One of these engineers was Captain Matthew Henry Phineas Riall Sankey, an Irishman who worked on defining the ideal “practical” steam machine, efficiency factor, and efficiency-measuring. While adding to the minutes of the Institution of Civil Engineers in 1898, he first used the diagram which would later be named after him.