In 1861 French mathematics teacher and inventor Augustin Mouchot designed and patented the first machine that generated electricity with from solar energy. By August 1866, Mouchot developed the first parabolic trough solar collector. He continued development and increased the scale of his solar experiments. Publication of his book on solar energy, La Chaleur solaire et ses applications industrielles. ("Solar Heat and its Industrial Applications") (1869), coincided with the unveiling of the largest solar steam engine he had yet built. This engine was displayed in Paris until the city fell under siege during the Franco-Prussian War in 1871, and was not found after the siege ended. Continuing his researches, Mouchot developed various machines for converting solar radition into mechanical power driven by steam. Mouchot's on the application of solar heat to industrial devices was primarily an historical review of previous efforts to power devices with solar energy.