ANIMAL HEAT 



575 



used, one containing the animal and the other a hydrogen flame, or a 

 coil of wire traversed by a voltaic current, which is regulated so as 

 to keep the temperature the same in the two calorimeters. From 

 the quantity of hydrogen burnt, or electricity passed, the heat- 

 production of the animal can be calculated. 



In Atwater's great respiration calorimeter (Fig. 195) both the heat 

 production and the respiratory exchange are measured. The heat 



FIG. 195* RESPIRATION CALORIMETER (ATWATER). 



Interior of chamber. A corner of the inner copper wall is supposed to be taken 

 away. The ventilating air -current enters the chamber at the lower end of W, 

 and leaves the chamber through the long tube fastened above W. The copper 

 tubes H, H are surrounded by copper discs I, I, fastened on them like a string 

 of beads to increase the surface. These tubes constitute the arrangement 

 through which the stream of water flows which removes the heat formed in 

 the chamber. J, J are copper troughs which receive the water dropping 

 from H, H. M, M, M are electrical thermometers which show the temperature 

 of the chamber ; N, N, similar thermometers which show the temperature of the 

 copper wall. 



produced by the person in the calorimeter is carried away from it 

 by a stream of water flowing through the chamber in a series of 

 tubes, the temperature within the calorimeter being kept constant by 

 regulating the temperature and velocity of the entering stream of 

 water. The quantity of the escaping water and the increase in its 



