August Beer

Who was August Beer?

August Beer was a German physicist, chemist, and mathematician. Beer was born in Trier, where he studied mathematics and natural sciences. Beer was educated at the technical school and gymnasium of his native town until 1845, when he went to Bonn to study mathematics and the sciences under the mathematician and physicist Julius Plücker, whose assistant he became later. In 1848 he won the prize for his essay, "De Situ Axium Opticorum in Crystallis Biaxibus," and obtained the degree of Ph.D. Two years later he was appointed lecturer at the University of Bonn.

In 1852, Beer published a paper on the absorption of red light in coloured aqueous solutions of various salts. Beer makes use of the fact, derived from Bouguer’s and Lambert’s absorption laws, that the intensity of light transmitted through a solution at a given wavelength decreases exponentially with the path length d and the concentration c of the solute. Actually, the “Absorption Coëfficient” defined by Beer in his paper is the transmittance, T = I / I0. Thus, as pointed out by Beer, the transmittance of a concentrated solution can be derived from a measurement of the transmittance of a dilute solution.