CALORIMETRY. 



411 



ventor as consisting of "two concentric boxes of sheet metal which 

 are fastened together so that there is a space of about 1J inches 

 between them, filled with water. The water box is 15 inches in 

 height and width, and 18 inches in length. An opening (h) 9 

 inches in diameter is made in one end for the entrance and exit of 

 the animal. It is also perforated with three small holes in the 

 top corners, and a slit-like opening in the top on one side. Two 

 of the holes are for the tubes for the entrance and exit of air (JEN 9 

 EX\ the entrance tube being carried close to the bottom, while 

 the exit tube extends only to the top of the box, and is placed in 

 the opposite diagonal corner, thus ensuring adequate ventilation. 

 In the third hole a thermometer (CT) is inserted, by means of 

 which the temperature of the calorimeter (jacket of metal and 

 water) is obtained. The opening in the side is for the insertion 

 of a stirrer ($), which is for the purpose of thoroughly mixing the 



EXT 



FIG. 229. Reichert's water calorimeter. 



water and thus equalizing the temperature of both water and 

 metal in other words, of the calorimeter." 



Before using the apparatus to determine the heat dissipated by 

 an animal, the calorimetric equivalent is determined i. e., the amount 

 of heat necessary to raise the temperature of the calorimeter 1 

 degree C. One gram of alcohol burned produces 9000 calories of 

 heat. If the burning of 10 grams raises the temperature of the 

 calorimeter 1 degree C., then the calorimetric equivalent will be 



