
Online temperature conversion for: Amonton, Barnsdorf, Beaumuir, Bénart, Bergen, Brisson, Celsius, Cimento, Cruquius, Dalencé, Dalton, Daniell, De la Hire, De la Ville, Delisle [Newer], Delisle [Older], De Luc, De Lyon, de Revillas, Derham [I], Derham [II], de Suede, de Villeneuve, Du Crest, Edinburgh, electron volts, Fahrenheit, Fahrenheit [Pre1707], Florentine [Large], Florentine [Small], Florentine Magnum, Fowler, Frick, Gas Mark, Goubert, Hales, Hanow [Newer], Hanow [Older], Hauksbee, JacobsHolborn, Kelvin, Kirch [Christine], Kirch [Gottfried], La Court, Lambert, Lange, Leiden, Ludolf, Mariotte, Miles, Murray, Newton, Oertel, Paris, Planck, Poleni, Réaumur, Rømer, Rankine, Richter, Rinaldini, Rosenthal, Royal Society of London, Sagredo, SaintPatrice, Stufe, Sulzer, Thermostat, Wedgwood [Original], and Wedgwood [Modernized]

Behold the ultimate temperature conversion machine.
In early 2010 I stumbled across some charts from some eighteenth and
nineteenthcentury sources on the subject of thermometers and was intrigued with the
vast number of temperature scales that proliferated in those days. Most seem pretty
obscure now, but many at one time or another, such as that of the Royal Society of
London, enjoyed great popularity.
The systems of Anders Celsius (17011744); William Thomson, 1st Baron Kelvin
(18241907); and Daniel Gabriel Fahrenheit (16861736) ultimately prevailed, of
course, but you may have heard of a few others.
The scale established by René Antoine Ferchault de Réaumur
(16831757), in which freezing is zero and boiling is 80 degrees, still finds some
use among European cheesemakers and often shows up in nineteenthcentury literature
such as Tolstoy’s War and Peace:
Christmas came and except for the ceremonial Mass, the solemn and wearisome Christmas
congratulations from neighbors and servants, and the new dresses everyone put on, there
were no special festivities, though the calm frost of minus twenty degrees Réaumur, the
dazzling sunshine by day, and the starlight of the winter nights seemed to call for some
special celebration of the season.

The Rankine scale is identical to the Fahrenheit, except that it avoids negative
numbers by initializing at absolute zero (459.67 °F). You encounter it from
time to time in engineering literature. Its name honors William John Macquorn
Rankine (18201872), who also left us the following comments regarding those
newfangled metric units he strove to avoid:
Some talk of millimetres, and some of kilogrammes,
And some of decilitres, to measure beer and drams;
But I’m a British Workman, too old to go to school,
So by pounds I’ll eat, and by quarts I’ll drink,
And I’ll work by my threefoot rule.


John Dalton

With the exception of the Dalton scale all of these are
linear. This means that given a known temperature scale reading of T_{1},
the unknown value for another scale, T_{2}, equals (m * T_{1}) + b
where m is called a slope and b a displacement. For Celsius to Fahrenheit, for
example, Fahrenheit = (1.8*Celsius) + 32. As in the cases of older and newer Delisle, de Revillas,
Hauksbee, and the Royal Society of London that slope can be negative. That indicates
their numbers go down with increasing kinetic energy rather than up. The Celsius scale
originally worked this way, with 100 freezing and 0 boiling, until it was flipped in the mid 1700s.
John Dalton’s system is logarithmic.
This is useful when you’re plotting temperatures that vary exponentially,
such as among different star types. Absolute zero is negative infinity in this
scale, freezing is 0.0 Daltons, water boils at 100, lead melts at around 253, and so
forth. Every hundred Daltons multiplies the thermodynamic energy by the ratio 373.15/273.15 or
approximately 1.37.
The converter below will translate between any pair of scales out of the 70. As a bonus it will display the
formula for a direct conversion between them — that’s 4830 total sets — along with the values of any
mathematical intersections. Since the Dalton scale is curved, it can share as many as two points with some linear ones.
0 Celsius = 32 Fahrenheit Formula: Fahrenheit = (1.8*Celsius) + 32
These two scales intersect mathematically at 40

Absolute zero  0 K  273.15°C  459.67°F 
Niobium superconducts  9.26 K  263.89°C  443.00°F 
Argon fluorohydride decomposes  17.15 K  256.00°C  428.80°F 
Lunar surface nighttime  40 K  233.15°C  387.67°F 
Pluto’s surface (mean)  44 K  229.15°C  380.47°F 
Nitrogen liquifies  77.36 K  195.79°C  320.42°F 
Titan’s surface (mean)  94 K  179.15°C  290.47°F 
Xenon freezes  161.3 K  111.85°C  169.33°F 
Satellitemeasured earth lows  179.817 K  93.33°C  136.00°F 
Carbon dioxide freezes (“dry ice”)  194.65 K  78.50°C  109.30°F 
Fahrenheit & Celsius intersect  233.15 K  40.00°C  40.00°F 
Mercury freezes  234.32 K  38.83°C  37.89°F 
Brown dwarf star WISE 08550714  238 K  35.15°C  31.27°F 
Ice and salt water bath  252.05 K  21.10°C  5.98°F 
Triethylborane (TEB) autoignites  253.65 K  19.50°C  3.10°F 
Hibernating arctic ground squirrel  270.25 K  2.90°C  26.78°F 
Water freezes  273.15 K  0.00°C  32.00°F 
Heavy water freezes  276.97 K  3.82°C  38.88°F 
Superheavy water freezes  277.64 K  4.49°C  40.08°F 
Lager fermentation (typical)  278 K  4.85°C  40.73°F 
Champagne serving (ideal)  281.15 K  8.00°C  46.40°F 
Wine storage (ideal)  285.9 K  12.75°C  54.95°F 
Earth’s surface (mean)  287.75 K  14.60°C  58.28°F 
Ale fermentation (typical)  294 K  20.85°C  69.53°F 
Room temperature (typical)  295.5 K  22.35°C  72.23°F 
Gallium melts  302.91 K  29.76°C  85.57°F 
Giant anteater body temp.  305.85 K  32.70°C  90.86°F 
Butter melts (typical)  306.65 K  33.50°C  92.30°F 
White phosphorus autoignites  307 K  33.85°C  92.93°F 
White chocolate melts (typical)  313.15 K  40.00°C  104.0°F 
Milk chocolate melts (typical)  315.65 K  42.50°C  108.5°F 
Dark chocolate melts (typical)  320.15 K  47.00°C  116.6°F 
Xenon hexafluoride melts  322.4 K  49.25°C  120.7°F 
Hottest recorded Earth temp.  330.95 K  57.80°C  136.0°F 
Water boils  373.15 K  100.0°C  212.0°F 
Heavy water boils  374.55 K  101.4°C  214.5°F 


Superheavy water boils  374.7 K  101.5°C  214.7°F 
Flaxseed oil smoke point  380.2 K  107.0°C  224.6°F 
Sulphur melts  388.4 K  115.2°C  239.4°F 
Lunar surface daytime  396.0 K  122.9°C  253.1°F 
Sugar carmelizes (typical)  441.5 K  168.4°C  335.0°F 
Kola Superdeep Borehole (12,262 m)  453.2 K  180.0°C  356.0°F 
Paper autoignites (typical)  505.0 K  231.9°C  449.3°F 
Mustard oil smoke point  527.2 K  254.0°C  489.2°F 
Amber melts  573.0 K  299.9°C  571.7°F 
Lead melts  600.6 K  327.5°C  621.4°F 
Mercury boils  629.9 K  356.7°C  674.1°F 
Zinc melts  692.9 K  419.7°C  787.5°F 
Venus’s surface (mean)  735.0 K  461.9°C  863.3°F 
Selfcleaning oven cycle (typical)  775.0 K  501.9°C  935.3°F 
Objects begin to glow red  798.0 K  524.9°C  976.7°F 
Buckminsterfullerene (C_{60}) sublimes  873.2 K  600.0°C  1,112°F 
Magnesium ribbon autoignites  903.0 K  629.9°C  1,166°F 
Cigarette tip during draw  973.2 K  700.0°C  1,292°F 
Table salt melts  1,074 K  800.9°C  1,474°F 
Gold melts  1,337 K  1,064°C  1,948°F 
Hardpaste porcelain firing  1,673 K  1,400°C  2,552°F 
Table salt boils  1,686 K  1,413°C  2,575°F 
Iron melts  1,811 K  1,538°C  2,800°F 
Lead boils  2,022 K  1,749°C  3,180°F 
Light bulb filament (typical)  2,820 K  2,547°C  4,616°F 
Gold boils  3,129 K  2,856°C  5,173°F 
Iron boils  3,134 K  2,861°C  5,182°F 
Oxyacetylene flame  3,350 K  3,077°C  5,570°F 
Diamond melts  3,550 K  3,277°C  5,930°F 
Tungsten melts  3,695 K  3,422°C  6,191°F 
Tantalum Hafnium Carbide melts  4,488 K  4,215°C  7,619°F 
Diamond boils  5,100 K  4,827°C  8,720°F 
Dicyanoacetylene flame  5,260 K  4,987°C  9,008°F 
Solar surface  5,799 K  5,526°C  9,979°F 
Tungsten boils  5,828 K  5,555°C  10,031°F 
Earth’s center (inferred)  6,230 K  5,957°C  10,754°F 

Please note that the conversions between temperatures on this page are
not guaranteed. The definitions of some of these scales, especially the
more obscure ones, fall far short of modern standards for precision and
reproducibility — so any results among them beyond two or three digits to the right of
the decimal point should be taken with a colossal grain of salt.
The units Gas Mark, Stufe, and Thermostat appear on some kitchen ovens
(in England, Austria, and France respectively) and their data comes from
Martha Stewart. Special thanks also to Benny Freilow, Beate and Rainer
Holland, and Enrico Schulze for their advice and enhancements. If you
spot any errors that you can correct, or know of any other scales I
might be able to include, please feel free to contact me.


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