Editing Kilogram (section)

=== Timeline of previous definitions ===
[[File:International prototype of the kilogram aka Le Grand K.jpg|thumb|right|The [[International Prototype of the Kilogram]], whose mass was defined to be one kilogram from 1889 to 2019.]]
* 1793: The [[grave (unit)|grave]] (the precursor of the kilogram) was defined as the mass of 1 [[litre]] (dm<sup>3</sup>) of water, which was determined to be 18841 [[Grain (unit)|grains]].<ref>{{cite book |title=Annales de chimie ou Recueil de mémoires concernant la chimie et les arts qui en dépendent |date=1792|url=https://books.google.com/books?id=FufDNJHvgFEC&q=18841+grains+grave&pg=RA1-PA278 |location= Paris |publisher= Chez Joseph de Boffe |page= 277 |volume = 15–16| last1=Guyton| last2=Lavoisier| last3=Monge| last4=Berthollet| display-authors=etal|author-link1=Louis-Bernard Guyton de Morveau| author-link2=Antoine Lavoisier| author-link3=Gaspard Monge| author-link4=Claude Louis Berthollet}}</ref> 
* 1795: the gram (<sup>1</sup>/<sub>1000</sub> of a kilogram) was provisionally defined as the mass of one cubic [[centimetre]] of water at the melting point of ice.<ref>{{lang|fr|Gramme, le poids absolu d'un volume d'eau pure égal au cube de la centième partie du mètre, et à la température de la glace fondante}}</ref>
* 1799: The [[Kilogramme des Archives]] was manufactured as a prototype. It had a mass equal to the mass of 1&nbsp;dm<sup>3</sup> of water at the temperature of its maximum density, which is approximately 4&nbsp;[[Celsius|°C]].<ref name="Zupko">{{cite book |last=Zupko |first=Ronald Edward| author-link =Ronald Edward Zupko|date=1990 |title=Revolution in Measurement: Western European Weights and Measures Since the Age of Science |url=https://archive.org/details/bub_gb_uYCNFkRgXCoC |location=Philadelphia |publisher=American Philosophical Society |isbn=978-0-87169-186-6}}</ref>
* 1875–1889: The [[Metre Convention]] was signed in 1875, leading to the production of the [[International Prototype of the Kilogram]] (IPK) in 1879 and its adoption in 1889.<ref>{{cite encyclopedia|url = http://www.britannica.com/EBchecked/topic/378767/Treaty-of-the-Metre|title = Treaty of the Metre|encyclopedia = [[Encyclopædia Britannica]]|access-date = 18 July 2023|year = 2023}}</ref>
* 2019: The kilogram was [[2019 revision of the SI|defined]] in terms of the [[Planck constant]], the [[speed of light]] and [[Caesium standard|hyperfine transition frequency of <sup>133</sup>Cs]] as approved by the [[General Conference on Weights and Measures]] (CGPM) on 16 November 2018.<ref name="vox"/>