The smallest steam engine in the world was built by Mr. D. A. A. Buck (American). The engine, boiler, governor and pumps stand in a space of seven-sixteenths of an inch square, or the area of a gold dollar and five-eighths of an inch high, composed of 148 distinct parts held together by 52 screws. Three drops of water fill the boiler to its proper capacity. Diameter of cylinder, one-sixteenth of an inch; length of stroke, three thirty-seconds of an inch; weight of engine, 15 grains.