Portrait of German chemist Robert Bunsen (left, 1811-1899), German physicist Gustav Kirchoff (centre, 1824-1887) and English chemist Henry Roscoe (right, 1833-1915). The photo was taken in 1862 during a visit by Bunsen and Kirchoff to Roscoe at Owens College, Manchester, England. Roscoe was the chair of chemistry at the time and had completed his PhD under Bunsen at the University of Heidelberg, Germany.