July 1897 Issue [Article] The century’s progress in physics. Part I.–The “imponderables” Download PDF Adjust Share by Henry Smith Williams, This article is only available as a PDF to subscribers. Download PDF Tags 19th century Augustin Jean Fresnel Electrodynamics Electromagnetic waves F. (François) Arago Force and energy Hans Christian Ãrsted Hermann von Helmholtz History James Clerk Maxwell James Prescott Joule John Tyndall Julius Robert von Mayer Light, Wave theory of Michael Faraday Physicists Physics Portraits Research Thermodynamics Thomas Young William Thomson, Baron Kelvin Adjust Share