Ice Calorimeter
a method of determining specific heats by means of ice. Black's calorimeter consists of a block of ice with a cavity in its center , with a cover of ice. The body, whose specific heat is to be determined, is raised to a certain temperature, and then put in the cavity. When the body falls to 32° F., the freezing point, it is wiped clean, as is the cavity itself, with a cloth previously weighed. The increase of weight in the cloth measures the ice converted into water, whence may be deduced the specific heat of the body, the rule being that 79.25, or in round numbers 80 thermal units, are needed to liquefy a pound of ice.