Hermann von Helmholtz had published the final…

Hermann von Helmholtz had published the final volume of his three-volume Handbook of Physiological Optics in 1867.

Helmholtz has studied the phenomena of electrical oscillations from 1869 to 1871, and in a lecture delivered to the Nat. Hist. Med. Ver. at Heidelberg on April 30, 1869 titled On Electrical Oscillations, he had indicated that the perceptible damped electrical oscillations in a coil joined up with a Leyden jar were about 1/50th of a second in duration.

Helmholtz has become interested in electrodynamics, which he attempts to relate to the conservation of energy.

In 1871, he announces that the velocity of the propagation of electromagnetic induction is about 314,000 meters per second.