# The 1855 Weber-Kohlrausch Experiment (The Speed of Light)

In the year 1855, German physicists Wilhelm Eduard Weber and Rudolf Kohlrausch performed an experiment with a Leyden jar and established the ratio between electrostatic and electrodynamic units of charge. This ratio became known as Weber’s constant and it is numerically equal to c√2, where c is the speed of light. In 1857, another German physicist Gustav Robert Kirchhoff used Weber’s constant to conclude that electric signals travel along a wire at the speed of light. A few years later in 1861, Scottish physicist James Clerk Maxwell was working on the physical medium responsible for magnetic lines of force and he had established a linkage between its transverse elasticity and the ratio of electrostatic to electromagnetic units of charge. Electromagnetic units of charge are related to electrodynamic units by a factor of √2. In order to evaluate this ratio, Maxwell looked up Weber’s results, and on converting Weber’s constant into electromagnetic units, the speed of light was exposed. This paper sets out to establish the fundamental origins of the speed of light.