Page "Fahrenheit" Paragraph 5

According to an article Fahrenheit wrote in 1724, he based his scale on three reference points of temperature.

In his initial scale ( which is not the final Fahrenheit scale ), the zero point is determined by placing the thermometer in brine: he used a mixture of ice, water, and ammonium chloride, a salt, at a 1: 1: 1 ratio.

This is a frigorific mixture which stabilizes its temperature automatically: that stable temperature was defined as 0 ° F (− 17. 78 ° C ).

The second point, at 32 degrees, was a mixture of ice and water without the ammonium chloride at a 1: 1 ratio.

The third point, 96 degrees, was approximately the human body temperature, then called " blood-heat ".