interesting, i never knew!
https://tutco.com/conductive/ask-ian-temperature-scales
it still seems a bonkers scale.
He used 3 points to create the scale: the freezing point of brine (a reproducible substance of ice, water, and salt), the freezing point of water , and the temperature of the human body.
The freezing point of brine was set at 0, and freezing temp of water was set to 32. This made the human body temperature 96.
This way, the number of degrees between brine and water was 32, a power of 2, and the number of degrees between water and the human body temperature was 64, another power of 2. Which means, in order to create a thermometer, he just had to make three marks at the known temperatures of 0, 32, and 96, and then bisect the distances between those marks a certain number of times (which is doable with just a rule and a compass), and he would have 96 evenly-spaced degrees from 0 to 96, which yields a usable thermometer with a large enough range of temperatures for a great many uses, including everyday temperatures.
The use of a brine mixture as a zero point isn't as arbitrary as you might think. Water, ice and ammonium chloride form what's called a frigorific mixture which is (to a degree) independent of both the quantity and temperature of the individual components. This means that the zero-point is reproducible, which is a requirement for any scientific unit of measurement.
https://www.reddit.com/r/askscience/comments/411rut/why_is_the_fahrenheit_scales_zero_point_at_such/
but practical.
A frigorific mixture is a combination of substances—most commonly ice and a salt—that produces a low, controlled temperature through an endothermic melting process. When the salt dissolves in surface moisture, it depresses the freezing point of water, forcing the ice to melt by absorbing heat from its surroundings.
https://en.wikipedia.org/wiki/Frigorific_mixture
glasspshr (npub14u3…ud9v)
