I don't think that's true. The Fahrenheit scale was originally defined to have 0° at the coldest measurable value at the lab bench (salt-water slurry), 32° at

I don't think that's true. The Fahrenheit scale was originally defined to have 0° at the coldest measurable value at the lab bench (salt-water slurry), 32° at the freezing point of water, and 96° for human body temperature. Why use those numbers? It's really easy to make even gradations with with powers of two: just half the length each time. Pretty clever, but of course this has a problem in that there's no guarantee that the three points are co-linear. So it was eventually redefined to simply be defined based upon the freezing/boiling points of water — from 32-212, based upon approximate extrapolations of the scale at the time. They may have even aimed for an even 180 degree separation between the two points. And this leads to the exact 9/5ths conversion ratio (212-32 / 100) from Celsius. I think the 37°C -> 98.6°F is just a coincidence. https://en.wikipedia.org/wiki/Fahrenheit#History https://en.wikipedia.org/wiki/Fahrenheit#History