40 



PRINCIPLES OF FEEDING FARM ANIMALS 



respiration chamber into a calorimeter. T.he original apparatus 

 built at Wesleyan University, Connecticut, has been further modi- 

 fied by Armsby and associates at the Pennsylvania station, where 

 an apparatus was built in 1898 by the Pennsylvania station, in 

 cooperation with the IT. S. Department of Agriculture. This appa- 

 ratus is sufficiently large to allow of investigations with mature 



Fig. 9. — A view of the respiration calorimeter at the Pennsylvania Experiment Sta- 

 tion. The calorimeter chamber in which the animal on the experiment is kept, to the left. 

 (Armsby.) 



cattle, and it is possible to continue the experiments for a con- 

 siderable length of time, if desired (Pig. 9). 



" The apparatus consists of a Pettenkofer respiration apparatus pro- 

 vided with special devices for the accurate measurement, sampling, and 

 analysis of the air-current. A current of cold water is led through copper 

 absorbing pipes near the top of the respiration chamber and takes up the 

 heat given off by the subject. The volume of water used being measured, 

 and its temperature when entering and leaving being taken at frequent 

 intervals, the amount of heat brotight out in the water-current is readily 

 calculated. To this is added the latent heat of the water-vapor brought out 

 in the ventilating air-current. By means of ingenious electrical devices, 

 . . . the temperature of the interior of the apparatus is kept constant, and 

 any loss of heat by radiation through the walls or in the air-current 

 is prevented." 2 



2 Armsby, " Principles of Animal Nutrition," p. 248. For a descrip- 

 tion of the respiration calorimeter and examples of methods of calculations, 

 see TJ. S. Department of Agriculture Year Book, 1910, pp. 307 to 318; Ex- 

 periment Station Record, vol. 15, p. 1037; Bur. Animal Ind. Bull. 128, 

 and Jr. Agric, Research, 3, p. 435. 



