Giovanni Giorgi#MKSA

Giovanni Giorgi was born in Lucca on November 27, 1871.

Giorgi 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 1905 and 1924. He also taught at the University of Rome between 1913 and 1939. During World War II he moved to Ferentino. He was an Invited Speaker of the ICM in 1924 in Toronto,{{cite book|author=Giorgi, Giovanni|chapter=On the functional dependence of physical variables|title=In: Proceedings of the International Congress of Mathematicians in Toronto, August 11–16. 1924|volume=2|pages=31–56}} in 1928 in Bologna, and in 1932 in Zurich.

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.{{cite book|last1=Mihaljević|first1=Helena|last2=Roy|first2=Marie-Françoise|author2-link= Marie-Françoise Roy |editor1-last=Araujo|editor1-first=Carolina|editor1-link=Carolina Araujo (mathematician)|editor2-last=Benkart|editor2-first=Georgia|editor2-link= Georgia Benkart |editor3-last=Praeger|editor3-first=Cheryl E.|editor3-link= Cheryl Praeger |editor4-last=Tanbay|editor4-first=Betül|editor4-link= Betül Tanbay |contribution=A Data Analysis of Women's Trails Among ICM Speakers|doi=10.1007/978-3-030-21170-7_5|pages=111–128|publisher=Springer International Publishing|series=Association for Women in Mathematics Series|title=World Women in Mathematics 2018|year=2019|volume=20 |arxiv=1903.02543|isbn=978-3-030-21169-1 |s2cid=70349983}}

Giorgi died on August 19, 1950, in Castiglioncello, Livorno at the age of 78.{{cite journal|url=https://physicstoday.scitation.org/do/10.1063/PT.6.6.20181127a/full/|doi=10.1063/PT.6.6.20181127a|date=November 27, 2018|journal=Physics Today|access-date=May 21, 2021|title=Giovanni Giorgi|issue=11 |page=4497 |bibcode=2018PhT..2018k4497. |s2cid=239840507 |url-access=subscription}}

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 {{Interlanguage link multi|Associazione elettrotecnica italiana|it}} (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.{{citation

|journal = Atti della Associazione Elettrotecnica Italiana

|location = Torino

|author = Giovanni Giorgi

|title = Unità Razionali di Elettromagnetismo

|language = Italian

|date = 1901

|ol = 18571144M

}}{{citation| author = Giovanni Giorgi | title = Rational Units of Electromagnetism. |year=1902}} [https://www.iec.ch/history/historical-documents Original manuscript with handwritten notes by Oliver Heaviside] {{citation

|volume = 9

|pages = 1–6

|author = Giovanni Giorgi

|title = Memorandum on the M.K.S. System of Practical Units

|journal = IEEE Magnetics Letters

|date = 1934

|doi = 10.1109/LMAG.2018.2859658

|doi-access = free

}}

{{citation

|title=The Life and Work of Giovanni Giorgi: The Rationalization of the International System of Units

|author = F. Frezza

|author2 = S. Maddio

|author3 = G. Pelosi

|author4 = S. Selleri

|journal = IEEE Antennas Propag. Mag.

|volume = 57

|pages = 152–165

|number = 6

|year = 2015

| issn = 1045-9243

| doi = 10.1109/MAP.2015.2486765|bibcode = 2015IAPM...57..152F

|s2cid = 42813124

}}

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.{{Citation

|journal = Proceedings of the National Academy of Sciences of the United States of America

|author = Arthur E. Kennelly

|title = 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

|date = 1935

|pages = 579–583

|volume = 21

|issue = 10

|doi = 10.1073/pnas.21.10.579

|pmid = 16577693

|bibcode = 1935PNAS...21..579K |pmc = 1076662

|author-link = Arthur E. Kennelly

|doi-access = free

}} 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.{{SIbrochure9th|page=205}}

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. The mole was added as a seventh base unit in 1971.{{Citation |author=National Institute of Standards and Technology |url=http://physics.nist.gov/cuu/Units/history.html | title=Brief history of the SI | access-date=2015-01-15|author-link=National Institute of Standards and Technology }}

• {{Cite book|title=Compendio delle lezioni di meccanica razionale|volume=|publisher=Sampaolesi|location=Roma|year=1928|language=it|url=https://gutenberg.beic.it/webclient/DeliveryManager?pid=6554225}}
• {{Cite book|title=Lezioni di fisica matematica|volume=|publisher=Sampaolesi|location=Roma|year=1928|language=it|url=https://gutenberg.beic.it/webclient/DeliveryManager?pid=6554768}}

{{reflist}}

1. {{cite web|author=International Electrotechnical Commission|title=IEC Historical Figures - Giovanni Giorgi|url=http://www.iec.ch/about/history/figures/giovanni_giorgi.htm|accessdate=2014-02-21|author-link=International Electrotechnical Commission|archive-date=2015-03-26|archive-url=https://web.archive.org/web/20150326102142/http://www.iec.ch/about/history/figures/giovanni_giorgi.htm|url-status=dead}}
2. {{Citation

|journal = Transactions of the International Electrical Congress, St. Louis, 1904

|url = https://archive.org/stream/transactionsint06conggoog#page/n144/mode/2up

|author = Giovanni Giorgi

|title = Proposals Concerning Electrical and Physical Units

|date = 1905

|pages = 136–141

|oclc = 3395740

|publisher = Albany, N.Y., J.B. Lyon Company

}}

{{Authority control}}

{{DEFAULTSORT:Giorgi, Giovanni}}

Category:1871 births

Category:1950 deaths

Category:Italian electrical engineers

Category:20th-century Italian physicists

Category:Metrologists

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