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
Breguet's thermometer Breguet's thermometer Breguet's thermometer, also called a spiral thermometer, is a type of thermometer which uses the expansion of metal under heat to produce a measurement more sensitive, and with a higher range, than both mercury and air thermometers. Working on the principle of a bimetallic strip, it consists of a very slender strip of platinum soldered to a similar strip of silver, with a slip of gold soldered in between. The strips of soldered metals are curved into a helix (a). The upper extremity of the helix is fastened to a metallic support (c) and the lower extremity is