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Webster 1913 Edition
Water thermometer
Wa′ter ther-mom′e-ter
.(Physics)
A thermometer filled with water instead of mercury, for ascertaining the precise temperature at which water attains its maximum density. This is about 39° Fahr., or 4° Centigrade; and from that point down to 32° Fahr., or 0° Centigrade, or the freezing point, it expands.