45 6 



PHYSIOLOGICAL PHYSICS. [Chap, xxxv. 



then completely burnt. The table is of great interest 

 from a physiological point of view. 



Potatoes . 

 Albumen . 

 Cabbage . 

 Carrot 

 Bread 

 Sugar 

 Rice 

 Starch 

 Ham (lean) 

 Veal (lean) 

 Milk 

 Beef (lean) 



6-114 

 6-460 

 8-958 

 9-036 

 8-883 

 8-958 

 4-175 

 6-141 

 4-118 

 2-206 

 2-615 

 5-383 



The greatest source of heat is, of course, the sun, 

 which not only gives us heat directly by its rays, but 

 indirectly, since the organic substances, by burning 

 which we obtain what heat we desire, could not have 

 been formed but for the influence of the sun's heat. 



Heat is also produced in capillary actions. 



CHAPTER XXXV. 



CONDUCTION, CONVECTION, AND RADIATION OF HEAT. 



Conduction of heat* If the end of a rod of 



copper be thrust into a fire, very soon not only the end 

 in the fire will become warm, but the other end also. 

 The heat will be propagated from one end of the bar 

 to the other, the tendency being to make the whole 

 bar of the same temperature. If a second bar be 

 placed in contact with the outer end of the first, the 

 heat will be passed on to it also. By the dynamical 

 theory, as we have seen, this propagation of heat by 

 conduction is not a transference of matter, but a 



