Reaction before Complete Equilibrium. 57 



potentials jjl, gh, \, v of one and the same component of the 

 system (mj or m 2 . . . or m n ) in the point or place A and those 

 in the point or place B, as well as the difference between the 

 values of one or more of the energies — the chemical energy, 

 gravitation energy, magnetic energy, Sfc. — of the unit of one 

 and the same independent component of the system in the 

 same two different points or places of the same, A and B, 

 is equal to the difference between the sum of the rest of the 

 energies of the unit of the given independent component (raj or 

 m 2 . . • or m n ) in the place B, and, the sum of the rest of the 

 energies of the same unit in the place A. Thus (/j, ] + \i + v,)in 

 A — (y^i +A-i + v 1 )in B or also {fi\-\-\ + v 1 )m 1 in the horizontal 

 plane A — (fjb 1 + \j + vj m 1 in the horizontal plane B, when 

 W!=l, is equal to the + work which will be done by gravity, 

 when the unit of the mass m x will be brought from the 

 horizontal plane B to the horizontal plane A. 



From the above ive also get the condition necessary that a 

 reaction should take place in the system, when its independent 

 components are affected by more than one potential. For this 

 it is necessary that the sum of all the potentials of each of the 

 independent components should, not be constant through the 

 whole sy stent, or that the condition (a) or (/3 ) should not be 

 fulfilled. 



If we pass to heterogeneous systems we are evidently able 

 to show, in the manner employed above by Gibbs, that at 

 equilibrium the sum. of all the potentials of one and the same 

 independent component, the temperature fyc. must be constant in 

 all parts and through the whole mass of the heterogeneous 

 system, and that a reaction takes place in the system when 

 this condition is not fulfilled. 



What interests us most is to have a substantial knowledge 

 about the ways and the velocities with which these thermal, 

 mechanical, and chemical equilibria are reached. Provided 

 no other phenomena interfere, we have for the velocity of 



cooling the law of Newton : = C(t — t), i. e. the velocity 



with which the heat passes from places of a higher tem- 

 perature to places of a lower temperature is directly pro- 

 portional to the difference of temperature, C being directly 

 proportional to the specific thermal conductivity of the given 

 substance. In application to heterogeneous systems this 



equation will assume the form =CZ(t —t),Le. it is directly 



proportional to the difference of temperature of the parts 

 between which an equalization of temperature takes place 



