Daily quote by Electromagnetism

• In a memoir... in 1858... published in... 1867, after the death of the author, Bernhard Riemann deduces the phenomena of the induction of electric currents from a modified form of Poisson's equation${\displaystyle {\frac {\mathrm {d^{2}} V}{\mathrm {d} x^{2}}}+{\frac {\mathrm {d^{2}} V}{\mathrm {d} y^{2}}}+{\frac {\mathrm {d^{2}} V}{\mathrm {d} z^{2}}}+4\pi \rho ={\frac {1}{a^{2}}}{\frac {\mathrm {d^{2}} V}{\mathrm {d} t^{2}}}}$where ${\displaystyle V}$ is the electrostatic potential and ${\displaystyle a}$ velocity.
  This equation is of the same form as those which express the propagation of waves and other disturbances in elastic media. The author, however, seems to avoid making explicit mention of any medium through which the propagation takes place.
  The mathematical investigation given by Riemann has been examined by Clausius, who does not admit the soundness of the mathematical processes, and shews that the hypothesis that potential is propogated like light does not lead either to the formula of Weber, or to the known laws of electrodynamics.
  • James Clerk Maxwell, A Treatise on Electricity and Magnetism (1881) Vol. 2, p. 446.