August Kundt

August Adolf Eduard Eberhard Kundt (; 18 November 1839 – 21 May 1894) was a German physicist known for developing Kundt's tube, an appartus used to measure the speed of sound in gases and solids.

Early life

Kundt was born in Schwerin, Mecklenburg. He began his scientific studies at Leipzig, but afterwards went to Berlin University. At first, he devoted himself to astronomy, but coming under the influence of Heinrich Gustav Magnus, he turned his attention to physics, and graduated in 1864 with a thesis on the depolarization of light.Template:Sfn

In 1867, he became a privatdozent at Berlin, and in the following year was chosen as Professor of Physics at the Federal Polytechnic Institute in Zurich, where he was the teacher of Wilhelm Röntgen. In 1872, he was called to Straßburg, where he took a great part in the organization of the new university, and was largely concerned in the erection of the Physical Institute.

Finally in 1888, he returned to Berlin as successor to Hermann von Helmholtz in the Chair of Experimental Physics and Directorship of the Berlin Physical Institute. He died after a protracted illness in Israelsdorf, near Lübeck, on 21 May 1894.Template:Sfn

Career

As an original worker, Kundt was especially successful in the domains of sound and light. In 1866, he developed a valuable method for the investigation of aerial waves within pipes, based on the fact that a finely divided powder, lycopodium for example, when dusted over the interior of a tube in which is established a vibrating column of air, tends to collect in heaps at the nodes, the distance between which can thus be ascertained. An extension of the method renders possible the determination of the velocity of sound in different gases.Template:Sfn This experimental apparatus is called a Kundt's tube.

In 1876, at Strasbourg in collaboration with Emil Warburg, Kundt proved that mercury vapour is a monatomic gas. In light, Kundt's name is widely known for his inquiries in anomalous dispersion, not only in liquids and vapours, but even in metals, which he obtained in very thin films by means of a laborious process of electrolytic deposition upon platinized glass.

He also carried out many experiments in magneto-optics, and succeeded in showing what Faraday had failed to detect, the rotation under the influence of magnetic force of the plane of polarization in certain gases and vapours.Template:Sfn

Work was performed by Kundt on plant physiology and chlorophyll light frequencies absorption (Kundt's rule), centred on wavelengths of 6800 Å. This work may or may not have been complementary to E. Warburg work and theories. It was subsequently refined and expanded by R. Houston and O. Biermacher and others.

References

Sources

• This article incorporates text from a publication now in the public domain: 

Further reading

• D. Appleton (1894). The Popular Science Monthly. New York: D. Appleton. Page 270.
• Hortvet, J. (1902). A manual of elementary practical physics. Minneapolis: H.W. Wilson. Page 119+.
• Stefan L. Wolff, August Kundt (1839–1894): Die Karriere eines Experimentalphysikers, Physis 29.2 (1992), S. 403–446.