Toward the end of the 19th century, after
James Clerk Maxwell's discoveries, it was clear that electric measurements could not be explained in terms of the three base units of length, mass and time, and that some irrational coefficients appeared in the equations without any logical physical reason. In 1901, Giorgi proposed to the (AEI) that the
MKS system (which used the
metre,
kilogram and
second as its base units) should be extended with a fourth unit to be chosen from the units of
electromagnetism, solving also the presence of the irrational coefficients. In 1935 this was adopted by the
International Electrotechnical Commission (IEC) as the
M.K.S. System of Giorgi without specifying which electromagnetic unit would be the fourth base unit. In 1946 the
International Committee for Weights and Measures (CIPM) approved a proposal to use the
ampere as that unit in a four-dimensional system, the MKSA system. The
Giorgi system was thus the precursor of the
International System of Units (SI) adopted in 1960, which was based on six base units: metre, kilogram, second, ampere,
kelvin, and
candela. ==Works==