Editing Absolute zero (section)

===Limit to the "degree of cold"===
The question of whether there is a limit to the degree of coldness possible, and, if so, where the zero must be placed, was first addressed by the French physicist [[Guillaume Amontons]] in 1703, in connection with his improvements in the [[gas thermometer|air thermometer]]. His instrument indicated temperatures by the height at which a certain mass of air sustained a column of mercury—the pressure, or "spring" of the air varying with temperature. Amontons therefore argued that the zero of his thermometer would be that temperature at which the spring of the air was reduced to nothing.<ref>{{Cite journal |last=Amontons |date=18 April 1703 |title=Le thermomètre rèduit à une mesure fixe & certaine, & le moyen d'y rapporter les observations faites avec les anciens Thermométres |trans-title=The thermometer reduced to a fixed & certain measurement, & the means of relating to it observations made with old thermometers |url=https://www.biodiversitylibrary.org/item/87349#page/216/mode/1up |journal=Histoire de l'Académie Royale des Sciences, avec les Mémoires de Mathématique et de Physique pour la même Année |language=French |pages=50–56}}  Amontons described the relation between his new thermometer (which was based on the expansion and contraction of alcohol (''esprit de vin'')) and the old thermometer (which was based on air).  From p. 52:  ''" […] d'où il paroît que l'extrême froid de ce Thermométre seroit celui qui réduiroit l'air à ne soutenir aucune charge par son ressort, […] "''  ([…] whence it appears that the extreme cold of this [air] thermometer would be that which would reduce the air to supporting no load by its spring, […])  In other words, the lowest temperature which can be measured by a thermometer which is based on the expansion and contraction of air is that temperature at which the air's pressure ("spring") has decreased to zero.</ref> He used a scale that marked the boiling point of water at +73 and the melting point of ice at +{{frac|51|1|2}}, so that the zero was equivalent to about −240 on the Celsius scale.<ref name="AS2016">{{Cite EB1911|wstitle=Cold}}</ref> Amontons held that the absolute zero cannot be reached, so never attempted to compute it explicitly.<ref>{{Cite journal |last=Talbot |first=G. R. |last2=Pacey |first2=A. C. |date=1972 |title=Antecedents of thermodynamics in the work of Guillaume Amontons |journal=Centaurus |volume=16 |issue=1 |pages=20–40 |bibcode=1972Cent...16...20T |doi=10.1111/j.1600-0498.1972.tb00163.x}}</ref> The value of −240&nbsp;°C, or "431 divisions [in Fahrenheit's thermometer] below the cold of freezing water"<ref>{{Cite book |last=Martine |first=George |title=Essays Medical and Philosophical |date=1740 |publisher=A. Millar |location=London, England, UK |page=291 |chapter=Essay VI: The various degrees of heat in bodies |chapter-url=https://books.google.com/books?id=tSm2Ws6bg0oC&pg=PA291}}</ref> was published by [[George Martine (physician)|George Martine]] in 1740.

This close approximation to the modern value of −273.15&nbsp;°C<ref name="sib2115"/> for the zero of the air thermometer was further improved upon in 1779 by [[Johann Heinrich Lambert]], who observed that {{convert|-270|C|F K}} might be regarded as absolute cold.<ref>{{Cite book |last=Lambert |first=Johann Heinrich |title=Pyrometrie |year=1779 |location=Berlin, Germany |oclc=165756016}}</ref>

Values of this order for the absolute zero were not, however, universally accepted about this period. [[Pierre-Simon Laplace]] and [[Antoine Lavoisier]], in their 1780 treatise on heat, arrived at values ranging from 1,500 to 3,000 below the freezing point of water, and thought that in any case it must be at least 600 below. [[John Dalton]] in his ''Chemical Philosophy'' gave ten calculations of this value, and finally adopted −3,000&nbsp;°C as the natural zero of temperature.