John Ericsson (1803-1889), a Swedish engineer noted for his invention of the screw propeller, the main form of marine propulsion to this day. He is also known for his early version of a solar-powered hot air engine. Ericsson designed and built the Monitor for the Union Navy in 100 working days. It featured his screw propeller with revolutionary features: a revolving gun turret, and iron (instead of wood) construction. The Monitor defeated the Confederate Merrimac in an epic U.S. Civil War maritime battle.
Ericsson demonstrated his engineering genius in many other areas. He improved transmission of power by using compressed air; he designed new types of steam boilers and condensers for marine steam engines; he designed and constructed an early steam locomotive; and he created an apparatus that made salt from brine. Around 1872, Ericsson built a displacer type (or Stirling) engine powered by a solar parabolic reflector, and a related thermodynamic cycle is named for him. Ericsson envisioned that Californian agriculturists would use his sun-motor for irrigation purposes, but this did not come to fruition.