Interestingly, the Fahrenheit temperature scale was set up because it's easy to calibrate independently of the boiling/freezing points of things at specific atm

Interestingly, the Fahrenheit temperature scale was set up because it's easy to calibrate independently of the boiling/freezing points of things at specific atmospheric pressure. A 1:1:1 mixture of ice, water and ammonium chloride will self-stabilize at a consistent temperature; that temperature is the zero point of the Fahrenheit scale. Fahrenheit also wanted the freezing point of water at 32 and human body temperature at 96 for easy marking on a thermometer (64 degrees between the two, easy to mark off halves and get the full scale).