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.
Mercury-in-glass thermometer about one million mercury thermometers (together containing about 1 tonne of mercury) were collected. By the Philippines Department of Health’s Administrative Order 2008-0221, all mercury equipment from hospitals, including mercury-in-glass thermometers, will be phased out in the Philippines by September 28, 2010. Even before the order was released, 50 hospitals have already banned mercury from their establishments. Among these fifty hospitals, the Philippine Heart Center was the first one to do so. San Juan de Dios Hospital, Philippine Children’s Medical Center, San Lazaro Hospital, Ospital ng Muntinlupa, Lung Center of the Philippines, the National Kidney and Transplant Institute, Manila Adventist