Delisle scale

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The Delisle scale is a temperature scale invented in 1732 by the French astronomer Joseph-Nicolas Delisle (1688–1768). It is similar to that of Réaumur. Delisle was the author of Mémoires pour servir à l'histoire et aux progrès de l'Astronomie, de la Géographie et de la Physique (1738).

He had been invited to Russia by Peter the Great. In 1732 he built a thermometer that used mercury as a working fluid. Delisle chose his scale using the temperature of boiling water as the fixed zero point and measured the contraction of the mercury (with lower temperatures) in hundred-thousandths. The Celsius scale too originally ran from zero for boiling water down to 100 for freezing water. This was reversed to its modern order some time after his death, in part at the instigation of Daniel Ekström, the manufacturer of most of the thermometers used by Celsius.

The Delisle thermometers usually had 2400 graduations, appropriate to the winter in St. Petersburg. In 1738 Josias Weitbrecht (1702–1747) recalibrated the Delisle thermometer with 0 degrees as the boiling point and 150 degrees as the freezing point of water. The Delisle thermometer remained in use for almost 100 years in Russia.

Thus, the unit of this scale, the Delisle degree (sometimes spelled de Lisle), is −2/3 of a kelvin (or a degree Celsius) and absolute zero is at 559.725 Delisle degrees.

Degree Delisle
Kelvin [K] = 373.15 − [°De] · 2/3 [°De] = (373.15 − [K]) · 3/2
Celsius [°C] = 100 − [°De] · 2/3 [°De] = (100 − [°C]) · 3/2
Fahrenheit [°F] = 212 − [°De] · 6/5 [°De] = (212 − [°F]) · 5/6
Rankine [°Ra] = 671.67 − [°De] · 6/5 [°De] = (671.67 − [°Ra]) · 5/6
Réaumur [°Ré] = 80 − [°De] · 8/15 [°De] = (80 − [°Ré]) · 15/8
Newton [°N] = 33 − [°De] · 11/50 [°De] = (33 − [°N]) · 50/11
Rømer [°Rø] = 60 − [°De] · 7/20 [°De] = (60 − [°Rø]) · 20/7

Degree Delisle
Kelvin	[K] = 373.15 − [°De] · 2/3	[°De] = (373.15 − [K]) · 3/2
Celsius	[°C] = 100 − [°De] · 2/3	[°De] = (100 − [°C]) · 3/2
Fahrenheit	[°F] = 212 − [°De] · 6/5	[°De] = (212 − [°F]) · 5/6
Rankine	[°Ra] = 671.67 − [°De] · 6/5	[°De] = (671.67 − [°Ra]) · 5/6
Réaumur	[°Ré] = 80 − [°De] · 8/15	[°De] = (80 − [°Ré]) · 15/8
Newton	[°N] = 33 − [°De] · 11/50	[°De] = (33 − [°N]) · 50/11
Rømer	[°Rø] = 60 − [°De] · 7/20	[°De] = (60 − [°Rø]) · 20/7

Comparison of temperature scales

Comparison of temperature scales
Comment	Kelvin	Celsius	Fahrenheit	Rankine	Delisle	Newton	Réaumur	Rømer
Absolute zero	0	−273.15	−459.67	0	559.725	−90.14	−218.52	−135.90
Coldest recorded surface temperature on Earth (Vostok, Antarctica - July 21, 1983)	184	−89	−128.2	331.47	283.5	−29.37	−71.2	−39.225
Fahrenheit's ice/salt mixture	255.37	−17.78	0	459.67	176.67	−5.87	−14.22	−1.83
standard pressure)	273.15	0	32	491.67	150	0	0	7.5
Average surface temperature on Earth	288	15	59	518.67	127.5	4.95	12	15.375
Average human body temperature ¹	309.95	36.8	98.24	557.91	94.8	12.144	29.44	26.82
(Al 'Aziziyah>Al 'Aziziyah, Libya - September 13, 1922)	331	58	136.4	596.07	63	19.14	46.4	37.95
standard pressure)	373.15	100	212	671.67	0	33	80	60
Titanium melts	1941	1668	3034	3494	−2352	550	1334	883
surface of the Sun	5800	5526	9980	10440	−8140	1823	4421	2909

¹ Normal human body temperature is 36.8 °C ±0.7 °C, or 98.2 °F ±1.3 °F. The commonly given value 98.6 °F is simply the exact conversion of the nineteenth-century German standard of 37 °C. Since it does not list an acceptable range, it could therefore be said to have excess (invalid) precision. Here's a [list] of various measurements.
Some numbers in this table have been rounded off.

External link

[Photo of an antique thermometer backing board c. 1758]—marked in four scales; the second is Delisle (spelled "de Lisle").

Temperature scale (measurement)>scales
Celsius		Fahrenheit		Kelvin
Delisle	Leyden	Newton	Rankine	Réaumur	Rømer
Conversion formulas

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