The German chemist and physicist Robert Wilhelm Bunsen (1811-1899) was one of the great experimental chemists and a pioneer of chemical spectroscopy.

Robert Bunsen was born on March 31, 1811, in the university town of Göttingen. His father was professor of linguistics and librarian at the university. Bunsen completed his advanced education at Göttingen, developing an extensive mastery of mathematics, physics, chemistry, and mineralogy. In later years, when his fame as an experimentalist was worldwide, Bunsen stated that "a chemist who is not a physicist is nothing."

With his strong practical bent and interest in the expanding industrial revolution, Bunsen studied blast furnace operations, the working of steam engines, and the physiochemical processes of the famed porcelain works at Sèvres. In later years his scientific discoveries contributed to the increased efficiency of some of these basic industries.

Bunsen established his reputation through his work in inorganic chemistry and his classical set of experiments in organic chemistry which involved the properties of the cacodyl series of compounds. These organic arsenic bodies were highly dangerous, and his work with them nearly cost Bunsen his life. A useful by-product of this research was his discovery of the antidote for arsenic poisoning.

In 1852 Bunsen succeeded Leopold Gmelin in Heidelberg. There he established his Institute of Chemistry, which soon attracted the most brilliant students from all over the world, including Edward Frankland, the developer of the theory of chemical valency, and Victor Meyer, the pioneer in the chemistry of benzene compounds.

A master craftsman, Bunsen developed many of the instruments for analytical chemistry, including the burner which bears his name but which had been used first in a primitive form by Michael Faraday. The ice calorimeter and many devices for gas analysis were the product of Bunsen's personal skill.

Bunsen contributed to the foundations of photochemistry in collaboration with H. E. Roscoe, determining the effect of light on the combining reactions of hydrogen and chlorine. This led Bunsen to the first effort to estimate the radiant energy of the sun.

The most fruitful collaboration of Bunsen was his work with Gustav Kirchhoff, the German physicist. By combining the Bunsen burner with the optical system pioneered by Joseph von Fraunhofer, the two scientists developed the science and art of spectroscopy. Since each chemical element rendered radiant by the heat source emitted a characteristic pattern of lines (spectrum), there had been developed the supreme instrument of chemical analysis. Bunsen and Kirchhoff soon discovered two hitherto-unknown elements, cesium and rubidium.

Further Reading

• A good account of Bunsen appears in volume 4 of J. R. Partington, A History of Chemistry (1964). Eduard Farber, ed., Great Chemists (1961), contains a short biographical sketch. Henry M. Leicester and Herbert S. Klickstein, A Source Book in Chemistry, 1400-1900 (1952), includes a description of Bunsen's work.