Fahrenheit proposed his temperature scale in 1724, basing it on two reference points of temperature. In his initial scale (which is not the final Fahrenheit scale), the zero point was determined by placing the thermometer in "a mixture of ice, water, and "salis Armoniaci" ammonium chloride or even sea salt". This combination forms a eutectic system which stabilizes its temperature automatically: 0 °F was defined to be that stable temperature. A second point, 96 degrees, was approximately the human body's temperature ("sanguine hominis sani", the blood of a healthy person). A third point, 32 degrees, was marked as being the temperature of ice and water "without the aforementioned salts".