Sal (quÃmica)
See also: Degree
Definition
The scale of temperature centigrade is a scale of relative Température, invented in 1742 by the Astronome and Physicien Swedish Anders Celsius.L' scale centigrade makes correspond its zero with the temperature of the melting ice and 100 with the boiling point of water under a Pression of a atmosphere to the sea level.
It is different from the scale of temperature Celsius.
History
At the end of the 17th century and at the beginning of 18th, the idea had been established that had to be based the thermometric scales, either on a fixed point and a rate of dilation, or on two fixed points, the choice of the point (S) fixes (S) remaining of arbitrary good part. The scale Réaumur had its zero at the freezing point of water, while other scales placed it elsewhere in order to avoid having positive and negative temperatures in the same context (like one day of winter, for example). The zero could correspond to a very cold standard, as it was the case of the scale Rømer and its direct descendant, the scale Fahrenheit. Centigrade also knew the thermometer Delisle which had its zero at the point of boiling of water and grew with the cold, having thus a reversed scale but which avoided the negative temperatures.
Thus the scale initially defined by Anders Celsius had its zero at the point of boiling of water and 100 degrees at its freezing point. Carl von Linné is often quoted like person in charge of the inversion of the Celsius scale after the death of its inventor, in 1744. One allots sometimes even original the Celsius scale to him, by referring to his work Hortus Cliffortianus , published in 1737, five years before Celsius. However, an attentive study of the known as work shows that the few temperatures which are quoted there cannot be into Centigrade. Linné met Fahrenheit in Holland and it is clear that it started to use the Fahrenheit scale once returned to Sweden. It seems that Linné gave up the latter when he learned the existence from work the Centigrade one.
After the death of Centigrade in 1744, thermometers graduated according to modern the Celsius scale appear in Météorologie under various names, such Celsius Novum , Ekström and Strömer . Linné followed these developments with great interest and was made manufacture a thermometer on modern scale by the manufacturer of measuring instruments Daniel Ekström in the neighborhoods of 1744. The direct scale is mentioned in an essay written by Samuel Naucler in 1745, but it does not allot its invention. The history of the thermometers published in the Newspaper of the royal Swedish Academy of sciences , in 1749 by Pehr Wargentin, secretary of the Academy, mentions Celsius, its successor Martin Strömer and the manufacturer of Ekström instruments when she discusses the direct scale, but Linné is not mentioned a whole. It seems well that we cannot allot the credit of this invention to only one person in particular.
It is at the time of the 9th General conference of the weights and measures (CGPM), in 1948, that the international Système sliced between the three terms “centigrade degree”, “centesimal degree”, and “Degree Celsius” in favor of the latter. The centesimal degree indicates also a Angle plan equal to the 1/400e of a Cercle ( Dictionnaire of the French Academy , 8th edition, 1932 - 1935); it is a synonym of Grade or Gon (its symbol is gon ).
Other scales
The other scales of temperature are: Newton (~ 1700), Rømer (1701), Fahrenheit (1724), Réaumur (1731), Delisle (1738), Rankine (1859), Kelvin (1862), Leyden (Ca 1894?) and Centigrade (1948). (Note that “Kelvin” is all in small letters because it is a unit of the international Système, even if it bears the name of Lord Kelvin).
See too
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