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.
Miller-Casella thermometer the ocean was always warmer than that below. Scientists aboard the HMS Challenger later questioned this assumption and made temperature measurements with reversing thermometers instead which wouldn't require the coldest water to be at the ocean's bottom. Nature article - Miller Casella thermometer Miller-Casella thermometer The Miller-Casella thermometer was a Six's thermometer with a double bulb used extensively by the "Challenger" expedition during the late nineteenth century. The thermomemeter was used for water temperature readings along 360 different research stations around the world's oceans. The thermometer, about 9 inches in length, was enclosed in a copper case and filled with