Fahrenheit (symbol °F) is a temperature scale based on one proposed in 1724 by the German physicist Daniel Gabriel Fahrenheit (1686–1736), after whom the scale is named. On Fahrenheit’s original scale the lower defining point was the lowest temperature to which he could reproducibly cool brine (defining 0 degrees), while the highest was that of the average human core body temperature (defining 100 degrees). There exist several stories on the exact original definition of his scale; however, some of the specifics have been presumed lost or exaggerated with time. The scale is now usually defined by two fixed points: the temperature at which water freezes into ice is defined as 32 degrees, and the boiling point of water is defined to be 212 degrees, a 180-degree separation, as defined at sea level and standard atmospheric pressure. By the end of the 20th century, most countries used the Celsius scale, rather than the Fahrenheit scale, with 100° between water’s freezing and boiling points on the Celsius scale. Fahrenheit remains the official scale for the following countries and territories: the Bahamas, Belize, the Cayman Islands, Palau, and the United States and its associated territories of American Samoa and the U.S. Virgin Islands (except Puerto Rico and Guam, with the former predominantely using Celsius and the latter equally using Celsius and Fahrenheit). Canada retains it as a supplementary scale that can be used alongside Celsius. The Rankine temperature scale was based upon the Fahrenheit temperature scale, with its zero representing absolute zero instead.