From left: National Einstein Memorial, Washington D.C., by Robert Berks (Photo courtesy of Dan Smith); painting of Louis Pasteur by Albert Edelfelt (1886); Charles Darwin ape charicature (Hornet Magazine, 1871); portrait of Monsieur de Lavoisier and his wife, chemist Marie-Anne Pierrette Paulze, by Jacques-Louis David (1788). (Images courtesy of Wikipedia.)