[fancyketchup]

Gah. Can we please stop with this bullshit already? Fahrenheit has nothing to do with body temperature. The human body temperature is ~100F by coincidence, not by design.

The Fahrenheit scale has 180 divisions (nice round number, evenly divisible by loads of integers) between the freezing point of water and the boiling point of water (212F-32F=180, for the math challenged). The 0F point is the equilibrium point of a frigorific mixture of equal parts ammonium chloride, ice, and water. One can easily produce two reference points for the F scale in a way that isn't sensitive to the local pressure using just ice brine (0F) and ice water (32F). The melting temperature of ice and the equilibrium temperature of the brine mixture are constant on the pressure scales and temperature scales available to metrologists before about the 19th century[1][2].

The same can't be said for the Celsius scale, which requires either a triple-point cell or a known atmospheric pressure (so that the boiling temperature of water is well-known).

Edit: So the close out the point, the Fahrenheit is a unit which is much better matched for the calibration tools and computational methods available around the time it was invented.

[1] Maybe a better way to state this sentence is that the temperatures are constant "to within the experimental uncertainty achievable at the time."

[2] It's well known to anyone who has ever cooked that water boils at an appreciably different temperature in Denver than in Los Angeles.