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. 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. Kundt 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. 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 ==