In the 1860s and 1870s advances on Woodward's design were made. Jacob Wothly of Aachen improved Woodward's design with a reflector and condenser of one metre (39.37 inches) diameter and a focus of two meters (about 6½feet), attracting much attention, and presented it to the French Academy of Sciences, October 8, 1860, and at the Societe Francaise de Photographie in early November 1860, selling the design to Disderi, reportedly for 20,000 francs soon after, who was awarded a medal for his enlarged photographs at the 1862 London International Exhibition. Further adjustments to the original design included a clockwork heliostat, such as that invented by Léon Foucault in 1862 and built by his son-in-law, to rotate the mirror in synchronisation with the Sun's passage to concentrate its light on the condenser lens.