•Following an international inquiry by the BIPM, which began in 1948, the 10th CGPM, in 1954, approved the introduction of the ampere, the kelvin and the candela as base
units, respectively, for electric
current, thermodynamic temperature
and luminous intensity. The nameInternational System of Units (SI) was given to the
system by the 11th CGPM in 1960. At the 14th CGPM in 1971 the current version of the SI was completed by adding the mole as base
unit for amount of substance,
bringing the total number
of base units to seven.