Mercury-in-glass thermometer ushered in a new era of accuracy and precision in thermometry, and is still to this day regarded as one of the most accurate thermometers available. The thermometer was used by the originators of the Fahrenheit and Celsius scales. Anders Celsius, a Swedish scientist, devised the Celsius scale, which was described in his publication "The origin of the Celsius temperature scale" in 1742. Celsius used two fixed points in his scale: the temperature of melting ice and the temperature of boiling water. This wasn't a new idea, since Isaac Newton was already working on something similar. The distinction of Celsius
Temperature measurement also to confounding with atmospheric pressure changes. These early devices were called thermoscopes. The first sealed thermometer was constructed in 1641 by the Grand Duke of Toscani, Ferdinand II. The development of today's thermometers and temperature scales began in the early 18th century, when Gabriel Fahrenheit produced a mercury thermometer and scale, both developed by Ole Christensen Rømer. Fahrenheit's scale is still in use, alongside the Celsius and Kelvin scales. Many methods have been developed for measuring temperature. Most of these rely on measuring some physical property of a working material that varies with temperature. One of the most common