Fahrenheit invented thermometers accurate and consistent enough to allow the comparison of temperature measurements between different observers using different instruments.

[8]: 1 Upon completing his apprenticeship, Fahrenheit ran off[6]: 111  and began a period of travel through the Holy Roman Empire, Sweden, and Denmark in 1707.

At the request of his guardians, a warrant was issued for his arrest with the intention of placing him into the service of the Dutch East India company.

[9]: 74 In addition to his interest in meteorological instruments, Fahrenheit also worked on his ideas for a mercury clock, a perpetual motion machine, and a heliostat around 1715.

[8]: 5–7 In 1717 or 1718, Fahrenheit returned to Amsterdam and began selling barometers, areometers, and his mercury and alcohol-based thermometers commercially.

[10] In that year, he published five papers in Latin for the Royal Society's scientific journal, Philosophical Transactions, on various topics.

In his second paper, "Experimenta et observationes de congelatione aquæ in vacuo factæ", he provides a description of his thermometers and the reference points he used for calibrating them.

In his book, The History of the Thermometer and Its Use in Meteorology, W. E. Knowles Middleton writes, I believe that much of the confusion [over the Fahrenheit scale] has resulted from believing that [Fahrenheit] meant exactly what he said [in his Royal Society article], and discounting the natural tendency of an instrumentmaker to wish to conceal his processes, or at least to obfuscate his readers.

[9]: 75 From August 1736 to his death, Fahrenheit stayed in the house of Johannes Frisleven at Plein Square in The Hague in connection with an application for a patent at the States of Holland and West Friesland.

Four days later, he received the fourth-class funeral of one who is classified as destitute, in the Kloosterkerk in The Hague (the Cloister or Monastery Church).

The Fahrenheit scale later was redefined to make the freezing-to-boiling interval exactly 180 degrees,[13] a convenient value as 180 is a highly composite number, meaning that it is evenly divisible into many fractions.

[18] The Fahrenheit scale was the primary temperature standard for climatic, industrial and medical purposes in English-speaking countries until the 1970s, presently mostly replaced by the Celsius scale long used in the rest of the world, apart from the United States, where temperatures and weather reports are still broadcast in Fahrenheit.