In 1902, H.E. Willsie and John Boyle Jr., two American engineers, built the first experimental solar power plant in Olney, Illinois. Their plant was based on an 1885 design developed by the French engineer Tellier. Between 1892 and 1908, Willsie and Boyle experimented with low temperature solar plants that used "hot boxes" to heat water. Their "hot box" solar power plant was patented in 1903, and the results were published on May 13th 1909 in Engineering News.