Daniel Gabriel Fahrenheit FRS (; German: ['fa???nha?t]; 24 May 1686 – 16 September 1736) was a physicist, inventor, and scientific instrument maker.
Fahrenheit was born in Danzig (now Gdansk, Poland), then a predominantly German-speaking Hanseatic city in the Pomeranian Voivodeship of the Polish–Lithuanian Commonwealth, but lived most of his life in the Dutch Republic (1701–1736) and was one of the notable figures in the Golden Age of Dutch science and technology.
A pioneer of exact thermometry, he helped lay the foundations for the era of precision thermometry by inventing the mercury-in-glass thermometer (first practical, accurate thermometer) and Fahrenheit scale (first standardized temperature scale to be widely used).
In other words, Fahrenheit's inventions ushered in the first revolution in the history of thermometry (branch of physics concerned with methods of temperature measurement).
From the early 1710s until the beginnings of the electronic era, mercury-in-glass thermometers were among the most reliable and accurate thermometers ever invented.