328 



AGRICULTURAL CHEMISTRY 



cylinder, which is lined with platinum, the cover, and a 



collar to hold the 

 cover in place 

 and tightly seal 

 the bomb. These 

 three parts of 

 the apparatus 

 are shown in 

 Fig. 96. 



The principle 

 involved in de- 

 termining the 

 caloric value of 

 a food is simple. 

 A weighed 

 amount of the 

 substance is 

 burned in the 

 calorimeter and 

 the rise in tem- 

 perature of the 

 water that sur- 

 rounds the bomb 

 is noted. The 

 combustion i s 

 carried on in 

 oxj^gen so as to 



Fig. 94. Bomb calorimeter used for determining 

 the caloric or heat-producing value of foods. 



be complete, and all means possible are employed to 

 secure accuracy of results. The substance to be burned, 

 if it is a material like flour, is made into a pellet by 



