Born 27 November 1871 Died 19 August 1950 (aged 78) Nationality Italian Occupation Engineer Engineering career Institutions University of Rome Projects Giorgi system of measurement
Giovanni Giorgi (27 November 1871 - 19 August 1950) was an Italian physicist and electrical engineer who proposed the Giorgi system of measurement, the precursor to the International System of Units (SI).
Giorgi was born in
Lucca and studied engineering at the Institute of Technology of Rome, he worked at Fornaci Giorgi in Ferentino, then was the director of the Technology Office of Rome between 1906 and 1923. He also taught at the University of Rome between 1913 and 1939. During World War II he moved to Ferentino. He was engaged to Laura Pisati, his former master's student who became the first woman invited to deliver a lecture at the fourth International Congress of Mathematicians (ICM), but she died in 1908 shortly before both her talk and their intended wedding. 
He was an Invited Speaker of the
ICM in 1924 in Toronto, in 1928 in Bologna, and in 1932 in Zurich.
Giorgi died in
Castiglioncello, Livorno at the age of 78.
The Giorgi system
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 Associazione elettrotecnica italiana (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. 
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. The  mole was added as a seventh base unit in 1971.
Mihaljevi?, Helena; Roy, Marie-Françoise (2019). "A Data Analysis of Women's Trails Among ICM Speakers". In Araujo, Carolina; Benkart, Georgia; Praeger, Cheryl E.; Tanbay, Betül (eds.). World Women in Mathematics 2018. Association for Women in Mathematics Series. Springer International Publishing. pp. 111-128. arXiv: . 1903.02543 doi: 10.1007/978-3-030-21170-7_5.
Giorgi, Giovanni. "On the functional dependence of physical variables". In: Proceedings of the International Congress of Mathematicians in Toronto, August 11-16. 1924. vol. 2. pp. 31-56.
Giovanni Giorgi (1901), "Unità Razionali di Elettromagnetismo", Atti della Associazione Elettrotecnica Italiana (in Italian), Torino, OL 18571144M
Giovanni Giorgi (1902), Rational Units of Electromagnetism Original manuscript with handwritten notes by Oliver Heaviside
Giovanni Giorgi (1934), "Memorandum on the M.K.S. System of Practical Units", Central Office of the International Electrotechnical Commission, London, 9: 1-6, doi: 10.1109/LMAG.2018.2859658
F. Frezza; S. Maddio; G. Pelosi; S. Selleri (2015), "The Life and Work of Giovanni Giorgi: The Rationalization of the International System of Units", IEEE Antennas Propag. Mag., 57 (6): 152-165, Bibcode: 2015IAPM...57..152F, doi: 10.1109/MAP.2015.2486765, ISSN 1045-9243
Arthur E. Kennelly (1935), "Adoption of the Meter-Kilogram-Mass-Second (M.K.S.) Absolute System of Practical Units by the International Electrotechnical Commission (I.E.C.), Bruxelles, June, 1935", Proceedings of the National Academy of Sciences of the United States of America, 21 (10): 579-583, Bibcode: 1935PNAS...21..579K, doi: 10.1073/pnas.21.10.579, PMC , 1076662 PMID 16577693
^ a b
International Bureau of Weights and Measures (2006), The International System of Units (SI) (PDF) (8th ed.), pp. 109, 110, ISBN , 92-822-2213-6 archived (PDF) from the original on 2017-08-14
National Institute of Standards and Technology, Brief history of the SI , retrieved
International Electrotechnical Commission. "IEC Historical Figures - Giovanni Giorgi" . Retrieved . Giovanni Giorgi (1905), "Proposals Concerning Electrical and Physical Units", Transactions of the International Electrical Congress, St. Louis, 1904, Albany, N.Y., J.B. Lyon Company: 136-141, OCLC 3395740