D 



THE GENERAL THERMODYNAMICAL SYSTEM 



OF GIBBS 



[Gibbs, I, pp. 55-lU; U9-m] 



J. A. V. BUTLER 



I. Introduction 



1. General Thermodynamic Considerations. At the head of 

 his memoir, "On the EquiHbrium of Heterogeneous Sub- 

 stances," Gibbs quotes the first and second laws of thermo- 

 dynamics, as stated by Clausius: 



* 



"Die Energie der Welt ist constant. 

 Die Entropie der Welt strebt einem Maximum zu." 



From these two principles he proceeds to deduce, with rigor 

 and in great detail, the conditions of equilibrium in heterogene- 

 ous systems containing any number of substances. As an 

 introduction to his method, we shall first outline the earlier 

 development of the laws of thermodynamics and discuss their 

 bearing on the question of equilibrium in material systems. 



The first law of thermodynamics, or the Principle of the 

 Conservation of Energy, was first stated in a general form by 

 Helmholtz in his memoir "On the Conservation of Force" 

 (1847). Starting with a denial of the possibility of perpetual 

 motion, and making use of the experimental results of Davy, 

 Joule and Mayer on the production of heat by the expenditure 

 of mechanical work and in the passage of electric currents 

 through conductors, Helmholtz arrived at the generalisation 

 that the sum of the energies of the universe is constant and 

 when energy of one kind disappears, an equivalent amount of 

 other kinds of energy takes its place. 



Lord Kelvin, in 1851, introduced the concept of the intrinsic 

 energy of a body as the sum of the total quantities of heat and 



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