The Conférence générale des poids et mesures (General Conference on Weights and Measures or CGPM) is one of the three organizations established to maintain the SI system under the terms of the Metre Convention (1875). It meets in Paris every four to six years. In 2002 the CGPM represented 51 member states and ten further associate members ⁽¹⁾. SI (disambiguation). ... The Metre Convention (or Convention of the Metre, or Convention du Mètre in French, its original language) of 1875 is an international treaty that established what is now known as the SI system. ... 1875 was a common year starting on Friday (see link for calendar). ...

CGPM Meetings

• 1^st (1889) - kilogram defined as mass of the international prototype kilogram (IPK) made of platinum-iridium and kept at the International Bureau of Weights and Measures, Sèvres, France. International prototype metre sanctioned.
• 2^nd (1897)
• 3^rd (1901) - Litre redefined as volume of 1 kg of water. Clarified that kilograms are units of mass, "standard weight" defined, standard acceleration of gravity defined endorsing use of grams force and making them well-defined.
• 4^th (1907) - carat = 200 mg adopted.
• 5^th (1913) - International Temperature Scale proposed.
• 6^th (1921) - Metre Convention revised.
• 7^th (1927) - Consultative Committee for Electricity (CCE) created.
• 8 ^th (1933) - need for absolute electrical unit identified.
• 9^th (1948) - ampere, coulomb, farad, henry, joule, newton, ohm, volt, watt, weber defined. Lowercase l adopted as symbol for litre. Both the comma and dot on a line are accepted as decimal marker symbols [1] (http://www1.bipm.org/jsp/en/ViewCGPMResolution.jsp?CGPM=9&RES=7).
• 10^th (1954) - kelvin, standard atmosphere defined. International System of Units (metre, kilogram, second, ampere, kelvin, candela) began.
• 11^th (1960) - metre redefined in terms of wavelengths of light. Hertz, lumen, lux, tesla adopted. New metric system given the official symbol SI for Système International d'Unités, the "modernized metric system". Prefixes pico-, nano-, micro-, mega-, giga- and tera- confirmed.
• 12 ^th (1964) - original definition of litre = 1 dm³ restored. atto- and femto- prefixes.
• 13^th (1967) - second redefined as duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium-133 atom at a temperature of 0 K. Degree Kelvin renamed kelvin. Candela redefined.
• 14^th (1971) - new SI base unit mole defined. Pascal, siemens approved.
• 15^th (1975) - peta- and exa- prefixes. Gray and becquerel radiological units.
• 16^th (1979) - candela, sievert defined. Both l and L provisionally allowed as symbols for litre.
• 17^th (1983) - metre redefined in terms of the speed of light, but keeps same length.
• 18^th (1987) - conventional values adopted for Josephson constant, K_J, and von Klitzing constant, R_K, preparing the way for alternate definitions of the ampere and kilogram.
• 19^th (1991) - new prefixes yocto-, zepto-, zetta- and yotta-.
• 20^th (1995) - supplementary SI units (radian and steradian) become derived units.
• 21^st (1999) - new SI derived unit, the katal = mole per second, for the expression of catalytic activity.
• 22^nd (2003) - both the comma and dot on a line are reaffirmed as decimal marker symbols [2] (http://www1.bipm.org/jsp/en/ViewCGPMResolution.jsp?CGPM=22&RES=10).

Events January-April January 8 - Herman Hollerith receives a patent for his electric tabulating machine January 22 - Columbia Phonograph is formed in Washington, DC. February 11 - Japan adopted; 1st Diet convenes in 1890 January 30 ? Crown Prince Rudolf of Austria and his mistress Marie Vetsera commit a double suicide in... The international prototype, made of platinum-iridium, which is kept at the BIPM under conditions specified by the 1st CGPM in 1889. ... Platinum is also a certification by the RIAA and other world recording industries, see: RIAA certification General Name, Symbol, Number Platinum, Pt, 78 Chemical series transition metals Group, Period, Block 10 , 6, d Density, Hardness 21. ... Alternate meaning: Iridium (satellite) General Name, Symbol, Number Iridium, Ir, 77 Chemical series transition metals Group, Period, Block 9, 6, d Density, Hardness 22650 kg/m3, 6. ... The Bureau International des Poids et Mesures (International Bureau of Weights and Measures, or BIPM) is a standards organization, one of the three organizations established to maintain the SI system under the terms of the Metre Convention. ... Events January 1 - Brooklyn, New York merges with New York City. ... 1901 was a common year starting on Tuesday (see link for calendar). ... The litre (or liter in US) is a metric unit of volume. ... Gee (navigation) is also the name of a WWII radio navigation device built and implemented by the RAF for use in night bombing. ... For Carat as a unit of purity see Carat (purity) The carat is a unit of mass used for gems. ... 1913 is a common year starting on Wednesday. ... Events January 7 - First transatlantic telephone call - New York City to London January 9 - Military rebellion crushed in Lisbon January 14 - Paul Doumer elected president of France January 19 - Britain sends troops to China February 12 - First British troops lad on Shanghai February 14 - Earthquake in Yugoslavia - 700 dead February... 1933 was a common year starting on Sunday (link will take you to calendar). ... Amp re can refer to: Amp re (car) Ampere (unit) Andr -Marie Amp re This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ... The coulomb, symbol C, is the SI unit of electric charge, and is defined in terms of the ampere: 1 coulomb is the amount of electric charge (quantity of electricity) carried by a current of 1 ampere flowing for 1 second. ... The farad (symbol F) is the SI unit of capacitance (named after Michael Faraday). ... The henry (symbol H) is the SI unit of inductance. ... The joule (symbol J, also called newton metre, or coulomb volt) is the SI unit of energy and work. ... This article is about the SI unit of force. ... The ohm is the SI derived unit of electrical resistance (derived from the ampere and the watt). ... The volt is the SI derived unit for electric potential and voltage (derived from the ampere and watt). ... The watt (symbol: W) is the SI derived unit for power. ... This article is in need of attention. ... 1954 was a common year starting on Friday (link will take you to calendar). ... The kelvin (symbol: K) is the SI unit of temperature, and is one of the seven SI base units. ... Atmospheric pressure is the pressure caused by the weight of air above any area in the Earths atmosphere. ... metre or meter, see meter (disambiguation) The metre is the basic unit of length in the International System of Units. ... The international prototype, made of platinum-iridium, which is kept at the BIPM under conditions specified by the 1st CGPM in 1889. ... This article is about the unit of time. ... Amp re can refer to: Amp re (car) Ampere (unit) Andr -Marie Amp re This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ... The kelvin (symbol: K) is the SI unit of temperature, and is one of the seven SI base units. ... The candela (symbol: cd, Latin for candle) is one of the seven SI base units. ... The hertz (symbol Hz) is the SI unit of frequency. ... For alternate uses of the term lumen, see lumen In physics, specifically photometry (optics), the lumen (symbol: lm) is the SI derived unit of luminous flux. ... For other meanings, see Lux (disambiguation). ... The tesla (symbol T) is the SI derived unit of magnetic flux density (or magnetic inductivity). ... The litre (or liter in US) is a metric unit of volume. ... General Name, Symbol, Number Caesium, Cs, 55 Series Alkali metals Group, Period, Block 1(IA), 6, s Density, Hardness 1879 kg/m3, 0. ... The SI system of units defines seven SI base units: fundamental physical units defined by an operational definition. ... The mole (symbol: mol) is one of the seven SI base units and is commonly used in chemistry. ... The pascal (symbol Pa) is the SI unit of pressure. ... The siemens (symbol: S) is an SI derived unit of measurement for electric conductance, being the inverse of the ohm (Ω), named after Werner von Siemens. ... A gray, (symbol: Gy), is the SI unit of energy for the absorbed dose of radiation. ... The becquerel (symbol Bq) is the SI derived unit of radioactivity, defined as the activity of a quantity of radioactive material in which one nucleus decays per second. ... 1979 is a common year starting on Monday. ... The candela (symbol: cd, Latin for candle) is one of the seven SI base units. ... The sievert (symbol Sv) is an SI derived unit of equivalent dose or effective dose (of radiation), and so is dependent upon the biological effects of radiation as opposed to the physical aspects, characterised by the absorbed dose (measured in grays). ... 1987 is a common year starting on Thursday of the Gregorian calendar. ... The magnetic flux quantum Φ0 is the quantum of magnetic flux passing through a superconductor. ... The quantum Hall effect is a quantum mechanical version of the Hall effect, observed in two-dimensional systems of electrons subjected to low temperatures and strong magnetic fields, in which the Hall conductance σ takes on the quantized values where e is the elementary charge and h is Plancks... Yocto (symbol y) is a SI prefix in the SI system of units denoting a factor of 10-24. ... Zepto (symbol z) is a prefix in the SI system of units denoting a factor of 10-21. ... Zetta (symbol Z) is a SI prefix in the SI system of units denoting 1021 or 1 000 000 000 000 000 000 000. ... Yotta (symbol Y) is a SI prefix in the SI system of units denoting 1024 or 1 000 000 000 000 000 000 000 000. ... In mathematics and physics, the radian is a unit of angle measure. ... The steradian (ste from Greek stereos, solid) is the SI derived unit of solid angle, and the 3-dimensional equivalent of the radian. ... Katal is the SI derived unit for catalytic activity. ... The mole (symbol: mol) is one of the seven SI base units and is commonly used in chemistry. ... This article is about the unit of time. ...

References

⁽¹⁾ CGPM Member States (http://www1.bipm.org/en/convention/member_states/)