WE KNOW little of his character, nor even what he looked like. His legacy of scientific writing is minute, being confined to five brief articles in Latin his Philosophical Transaction. But his name has been a household word for centuries and he left an indelible mark upon the world. Gabriel Daniel Farhenheit was born 310 years ago today, on May 14th, 1686, and was the originator of the scale of temperature that bears his name.
Farhenheit was born into a wealthy merchant family in the German city of Danzig. When he was orphaned at the age of 15, his guardian sent him to Amsterdam to learn a trade and, in due course, he supported himself by manufacturing meteorological instruments of novel design, particularly hygrometers and thermometers. It was in 1724 that he devised his temperature scale which, in the form we know today, has 32 as the freezing point of water and a boiling point of 212.
Farhenheit, however, was by no means the only one to dabble in such matters. Indeed, between the years 1641 and 1780 at least 35 different scales of temperature were proposed. The proliferation is illustrated by a device to be found in the Royal Maritime Museum at Greenwich, which consisted of a circular plate with a pivoting arm, described as a "General Thermometer": manufactured about 1720, it is engraved with 16 different thermometer scales, and provided an easy means of converting a reading from one temperature scale into any of the 15 others.
Most of the scales on the General Thermometer are quite unfamiliar to us now. The Fontex Scale, for example, had a freezing point of -33 and a boiling point of 245; on the Paris Scale the corresponding points were 24.5 and 238, on the Cruquis 106 and 151, and on the Edinburgh Scale, 8 and 47. Two of the featured scales were constructed in such a way as to give diminishing numbers for increasing temperatures: the Royal Society Scale had a freezing point of 79 and a boiling point of 170, and the De Lisle ranged from 150 down to zero.
The other temperature scales engraved upon the instrument are the La Hine, the Hales, two scales devised by Rene Antoine de Reaumur and two described as "Florence", together with the Nenton, Amerton and Poleni Scales and, of course, the Farenheit. Celsius, alas, is missing, since the scale devised by Anders Celsius, the one mainly employed today throughout the world outside the US, did not come into common use until 20 years after the manufacture of this "General Thermometer".