Daniel Gabriel Fahrenheit Hague and was buried there at the Kloosterkerk (Cloister Church). According to Fahrenheit's 1724 article, he determined his scale by reference to three fixed points of temperature. The lowest temperature was achieved by preparing a frigorific mixture of ice, water, and ammonium chloride (a salt), and waiting for it to reach equilibrium. The thermometer then was placed into the mixture and the liquid in the thermometer allowed to descend to its lowest point. The thermometer's reading there was taken as 0 °F. The second reference point was selected as the reading of the thermometer when it was placed in still
Frog thermometer Frog thermometer The frog thermometer or - as the Cimento academicians defined it, the "botticino" [small-toad] thermometer - contained small glass spheres of different density, which were immersed in alcohol. The device was used as a clinical thermometer, tied to the wrist or the arm of the patient with the head of the frog facing upward. The variations in body temperature were registered by the movement of the spheres. The rise in temperature causes an increase in the volume of the alcohol, reflected in the movement of the small spheres (first the less dense, then the more dense). Because of