Mercury-in-glass thermometer related to the rapid cooling (and contraction) of the glass. When Celsius decided to use his own temperature scale, he originally defined his scale "upside-down", i.e. he chose to set the boiling point of pure water at 0 °C (212 °F) and the freezing point at -100 °C (-32 °F). One year later, Frenchman Jean-Pierre Christin proposed to invert the scale with the freezing point at and the boiling point at . He named it Centigrade (100 grades). Finally, Celsius proposed a method of calibrating a thermometer: These points are adequate for approximate calibration but both vary with atmospheric pressure.
Candy thermometer Candy thermometer A candy thermometer, also known as a sugar thermometer, or jam thermometer is a cooking thermometer used to measure the temperature and therefore the "stage" of a cooking sugar solution. (See Candy making for a description of sugar stages.) These thermometers can also be used to measure hot oil for deep frying. There are several kinds of candy thermometers available. These include traditional liquid thermometers, coil spring "dial" thermometers and digital thermometers. The digital thermometers tend to read the temperature more quickly and accurately, and some models have an alarm when the thermometer hits a certain temperature. Many