Talk:Fahrenheit

History vs. Speculation
The article claims that Fahrenheit took the melting point (7.5) and body temperature (22.5) of the Rømer scale and multiplied by 4, obtaining 30 and 90 respectively (which he then adjusted in a second step). How can this be brought into alignment that a temperature of 22.5°Rø is about 28.5°C, i.e. far below body temperature (even for measurement accuracy at that time)?

Furthermore:
 * I can't find any article about the Rømer scale mentioning the 22.5 as a fix point for body temperature. It only seems to be mentioned in tales on how Fahrenheit supposedly derived his scale.
 * The referenced source for the translated letter to Herman Boerhaave only contains a short quote saying ...use 96 instead of 22½ or 90..., without stating where the 22.5 come from or what it should mean. — Preceding unsigned comment added by 2A02:908:1E7:3980:0:0:0:DC8B (talk) 00:27, 22 December 2022 (UTC)


 * Yes. Fahreneit's preference for 96 as against 90 or 22½ is easy to understand in terms of dividing an instrument's scale. A dial of 360° can easily be divided into 180°, 90°, 45° and 22.5°, but Fahreneit was making linear scales. By calling his fixed points 0, 32 and 96 he could easily divide the spaces between them, the space between 0 and 32 being repeatedly halved to divisions of 16, 8, 4, 2 and 1, and likewise the space between 32 and 96. I don't understand him to be saying Rømer used 22.5 for blood temperature, only that he prefers dividing 0/32/96 to dividing down from 90. NebY (talk) 16:06, 22 December 2022 (UTC)
 * I've done a deep dive on this and I'm still diving. But basically, yeah, there is a lot of speculation on how the scale was developed and there is a lot of bad information out there about how the scale was developed. I'm working on fixing this up the best I can and have been digging through old books and papers to help sort out this history. Nysus (talk) 16:31, 6 December 2023 (UTC)

Liberia is not a former US colony
The intro describes various countries around the world which use the fahrenheit scale, and ends by calling Liberia a former American colony. While Liberia was founded by black Americans, it was never officially an American colony. 84.69.165.8 (talk) 10:22, 18 October 2023 (UTC)


 * It wasn't a chartered or state-sponsored colony of the United States of America, true, but we don't call it a US colony. As you say, it was colonised by Americans, specifically the American Colonization Society, as described in Liberia. NebY (talk) 11:55, 18 October 2023 (UTC)

Formalisation versus invention
I've made a change to the article regarding a claim that Celsius was formalised about 20 years after.

Based on sources available, it seems like it is a bit of a stretch & inaccuracy to say that it was formalised at that time, when it was actually invented then and not adopted widely or backed by any institution at that time.

Just posting here to inform others of the intent behind my change, as I think the wording for this does change the meaning. Cbrfield (talk) 17:57, 23 November 2023 (UTC)

Anyone want to help untangle the true story of the Fahrenheit scale?
I've recently read a fair amount about how Fahrenheit developed his scale which I've somewhat outlined in the Daniel Gabriel Fahrenheit page: Daniel Gabriel Fahrenheit. The basic story, as best I can tell, is this:

1) In 1724, Fahrenheit wrote a paper (one of five papers) called "Experimenta et observationes de congelatione aquae in value factae" that was published in the scientific journal for the Royal Society, "Philosophical Transactions." I haven't found a translation for this paper, written in Latin, but accoring to second-hand sources, he talks about using salt water mixture as a reference point for 0F and body heat as another. For over 200 years, Fahrenheit's paper the only documentation of how he developed his scale and this was blindly accepted as the truth.

2) Then, in 1936, a professor named Ernst Cohen and his wife, W. A. T. Cohen uncovered a 1729 correspondence between Fahrenheit and famous scientist, Herman Boerhaave. To make a long story short, Fahrenheit explained that his thermometers were based on Rømer's temperature scale. And according to a journal left behind by Rømer, the only two reference points he used were the freezing point of fresh water (with no salts mixed in) and the boiling point of water.

3) Also in his correspondence, Fahrenheit talks about how he said Rømer was using "blood heat" for his 22.5 degree reference point. It's speculated that this was a misunderstanding on Fahrenheit that this meant body temperature. However, it's actually thought that this was just a shorter version of one of Rømer's thermometers which originally went all the way up to the boiling point of water which was unnecessary for regular meteorological readings which he was using them for.

So the question becomes, why did Fahrenheit apparently lie about the basis for his scale? In his book about the history of thermometers, Middleton speculates that it was to obfuscate how he made his thermometers. See, Fahrenheit not only invented accurate thermometers but he sold them commercially. Giving away any trade secrets would be a bad idea.

Another great book I found which covers this topic is called "Fahrenheit's Letters to Leibniz and Boerhaave" by Pieter van der Star. He believes that between 1708 and 1713, a few years before he sold his thermometers commercially, Fahrenheit stopped using body heat as a calibration point and, as far as I can tell, based his thermometer merely on the volume of the void in the thermometer and the amount of mercury in the thermometer. I could be wrong on this. Things get fairly technical and I haven't dived into this aspect of how Fahrenheit developed his thermometers.

I've looked around on the internet and most sources have a very bad understanding of the history of the Fahrenheit scale. I'm trying to ensure wiki has the most accurate version of its development. If you are interested in helping me unravel this story, let me know. Nysus (talk) 17:51, 5 December 2023 (UTC)