Ludvig Lorenz, Electromagnetism, and the Theory of Telephone Currents
  Ludvig V. Lorenz (1829-1891) was Denmark's first theoretical physicist and the only one whose work attracted international attention in the second half of the nineteenth century. This paper presents a survey of Lorenz's contributions to physics with an emphasis on his work in electrodynamics and electrical science. His 1867 electrodynamic theory of light was of a theoretical and foundational nature, while his unpublished theory of telephone currents was oriented toward practical problems in long-distance telephony. Lorenz's theories are briefly compared to those of better known physicists such as H. A. Lorentz, J. C. Maxwell, and O. Heaviside. 
Helge Kragh
physics.hist-ph