The Armstrong effect is the physical process by which static electricity is produced by the friction of a fluid. It was first discovered in 1840 when an electrical spark resulted from water droplets being swept out by escaping steam from a boiler. The effect is named after William Armstrong, who later became 1st Baron Armstrong, who was one of several people involved in discovering the effect and investigating the processes involved.[1] Using this principle Armstrong went on to invent what he called the Armstrong Hydroelectric Machine, which, despite its name, generated static electricity and not hydroelectric power.