Daniel Gabriel Fahrenheit research suggests that the Fahrenheit family originated in Hildesheim. Daniel's grandfather moved from Kneiphof in Königsberg (present-day Kaliningrad) to Danzig and settled there as a merchant in 1650. His son, Daniel Fahrenheit (the father of the subject of this article), married Concordia Schumann, daughter of a well-known Danzig business family. Daniel was the eldest of the five Fahrenheit children (two sons, three daughters) who survived childhood. His sister, Virginia Elizabeth Fahrenheit, married Benjamin Ephraim Krueger of an aristocratic family from Danzig. Daniel Gabriel began training as a merchant in Amsterdam after his parents died on 14 August 1701 from eating
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