# What is Faraday's First Law

Michael Faraday wrote in his "Experimental Studies on Electricity" in 1821:

§ 360"The general conclusion that I believe must be drawn from the sum of facts is that all electricity, from whatever source, is essentially identical."
(Note: This refers to "atmospheric electricity", "frictional electricity", "galvanic electricity", "thermoelectricity" and "induction electricity", which were examined in the previous paragraphs.)
§ 361"After I believed the identity had been sufficiently established, my next endeavor was to obtain a common measure or known quantity relation between that excited by an electrifying machine and the electricity of a voltaic pillar."
§ 377

Faraday finds that "the chemical as well as the magnetic force is directly proportional to the absolute quantity of the electricity passed through."
This is the original formulation of Faraday's first law.

§ 504"The sum of the chemical composition is constant for every cross-section of a conductor subject to decomposition and of uniform nature, whatever the distance between the poles or the cross-section may be."
§ 505"For a constant quantity of electricity, for every conductor subject to decomposition, let it consist of water, salt solutions, acids, molten bodies, etc., the amount of electrochemical action is also a constant quantity. what we call electric current [...] is present [...] as the axis of a total force consisting of opposing, directed forces ".
§ 783

"The chemical force of an electric current is directly proportional to the absolute amount of electricity passed through."
Faraday gives (as everywhere in his works) no mathematical expression for this. If the mass m of a deposited metal is used for the "chemical force", according to today's notation (q = amount of charge):
m ~ q

§ 821provides the proportionality factor from experiments using equivalence masses:
"The results obtained with any substance do not merely agree with one another, but also with those obtained with other substances, so that all combine together in a series of fixed electrochemical actions."
§ 836"Electrochemical equivalents are the same as ordinary chemical equivalents."
This provides the above proportionality factor by putting the equivalent mass and charge in relation to one another. The second Faraday's law reads in the usual formulation: "The same amounts of electricity separate different substances in the ratio of their chemical equivalent masses."
 For q = const. M. = molar mass n = Number of electrons exchanged

Both laws can be summarized: