1674-1727

German engineer who collected, for the first time in print, the basic principles of mechanical engineering. Leupold's nine-volume treatise, The General Theory of Machines, helped systemize the current knowledge of the day. It also contained the first description of a noncondensing steam engine—that is, one in which the steam is released into the atmosphere after use in the engine. This was very similar to the first such engines actually built over 50 years later.