Caption:
Gustav Robert Kirchhoff, German physicist, 1873. Kirchhoff (1824-1887) is known for his work on electricity, heat and optics. His collaboration with Robert Wilhelm Bunsen (1811-1899) on spectrum analysis led, in 1859, to the discovery of caesium and rubidium. He also formulated two laws governing electric networks. From The Science Record. (New York, 1873).