148 Experimental Investigations 



to conclude that if the cylinder were composed of three 

 particles of matter only, A, C, E, the particle C, which 

 is in the middle of the cylinder, must necessarily have 

 the arithmetical mean temperature between that of A 

 and that of E, which are at the two extremities of the 

 cylinder; that is to say, between 212 and 32 of Fah- 

 renheit, which is 122. 



Now let us interpose between the particles A, C, and 

 E, two other particles, B, D, and see whether the intro- 

 duction of these two particles will make any change in 

 the temperature of the particle C that occupies the mid- 

 dle of the cylinder. 



If the particle B be placed in the middle of the space 

 comprised between the extremity, A, of the cylinder and 

 its middle, C, it ought to acquire a mean temperature 

 between that of the extremity, A, of the cylinder, and 

 that of the point C, namely that of 167, the mean be- 

 tween 212 and 122; and if the particle D be placed in 

 the midst of the space comprised between the middle 

 of the cylinder and its other extremity, E, this particle 

 ought to acquire a mean temperature between that of 

 the middle of the cylinder and that of its extremity, E ; 

 it ought then to have the temperature of 77. 



From this new arrangement, the particle C, situate 

 in the middle of the cylinder, will find for its neigh- 

 bours, on one side the particle B, at the temperature of 

 167, and on the other the particle D, at that of 77. 

 The point in question is, whether the presence of these 

 two particles will make any change in the temperature 

 of the particle C, or not. 



In the first place, it is evident that if the calorific in- 

 fluences of the particle B on the particle C be as effica- 

 cious in heating it as the frigorific influences of the 



