LORENZ, L. (LUDWIG VALENTIN) - LIGHT IS IDENTICAL WITH ELECTROMECANICAL WAVES.

Om Identiteten af Lyssvingninger og elektriske Stømme. (On the Identity of the Vibrations of Light with electrical Currents).

(København, 1867). Contemp. marbled clothbacked boards. Titlelabel with gilt lettering on upper cover. Pp. 26-45. Extracted from "Oversigt over det Kgl. danskeVidenskabernes Selskabs Forhandlinger 1867, Nr. 1".

Extremely scarce first edition of the paper in which Lorenz, independent of Maxwell, stated that light is electromechanical in nature, probably inspired by his former teacher H. C. Oersted, the discoverer of electromagnetism and professor at the Polytechnic College, he aimed at unifying the forces of nature without introducing new physical hypotheses. "The idea that the various forces in nature are merely different manifestations of the one and same force has proved itself more fertile than all physical theories".


Most impressive of all Lorenz’ achievements in optics is his electromagnetic theory of light, developed in a relatively unknown paper of 1867, two years after Maxwell’s famous paper on the same subject. At that time Lorenz did not know Maxwell’s theory, and his own approach was quite different. Lorenz’ electromagnetic theory of light can be described briefly as an interpretation of the light vector as the current density vector in a medium obeying Ohm’s law. This paper contains the fundamental equations for the vector potential and the scalar potential or - for the first time - the corresponding retarded potentials expressed in terms of the current density vector and the electrical charge density. The concept of retarded potentials had already been introduced in an earlier paper by Lorenz in connection with research on the theory of elasticity. He found that the differential equation for the current density vector was the same as his fundamental wave equation for the light vector, completed with a term which explains the absorption of light in conducting media, and that his theory led to the correct value for the velocity of light." (Mogens Pihl in DSB).

The paper was published in English, 1867 "On the identity of the vibrations of light with electrical currents." (Philosophical Magazine 34: 287-301) and also in German in "Annalen der Physik"

Order-nr.: 55371