Thermometric Scale

—The graduated scale to which thermometers are referred. The common scale is Fahrenheit’s, in which zero is the temperature of a mixture of salt and snow, 32° that of melting ice, and 212° that of boiling water. For temperatures between 212° and 400° Fahr., comparisons should be made with the temperatures given in Regnault’s Steam Tables, by placing the thermometer in a well of mercury surrounded by saturated steam under sufficient pre ure to give the desired temperature. The Celsius and Réaumur scales run from the temperature of melting ice to that of boiling water, the. former having 100 graduations and the latter 80, hence, the Celsius is called the Centigrade thermometer.