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111. On the Velocity of Reaction before Complete Equilibrium 

 and before the Point of Transition^ Sfc. Part I. By 

 Meyer Wildekman, Ph.D., B.Sc. (O.von.) *. 



[Plates I. & II.] 



Contents. 

 Pabt I. 



I. J. W. Gibbs's general thermodynamic principles concerning- equili- 

 brium of heterogeneous systems. The general principles concerning 

 velocity of reaction. Extension of the same for components with 

 several potentials. Gibbs's rule of phases. 

 II. Experiments on the velocity of reaction before complete equilibrium 

 and the point of transition are reached : 



(a) The results achieved from earlier experiments. 



(b) The later research at the Davy-Faraday Laboratory. 



III. The method emphwed. 



IV. The results obtained. The general law concerning all velocities of 



reaction before complete equilibrium and before the point of trans- 

 ition of the system are reached. 



Part I. 



I. J. W. Gibbs's General Thermodynamic Principles con- 

 cerning Equilibrium in Heterogeneous Systems. The 

 General Principles concerning Velocity of Reaction. 

 Extension of the same for Components with several 

 Potentials. Gibbs's Ride of Phases. 



IN his classical work " Graphical Methods in the Thermo- 

 dynamics of Fluids'' (Transactions of the Connecticut 

 Academy of Arts and Sciences, 1873, vol. ii, p. 309) and 

 u On the Equilibrium of Heterogeneous Substances " (1875- 

 1878, vol. iii. pp. 108, 343), J. Willard Gibbs gave us a very 

 detailed theoretical investigation of all kinds of chemical and 

 physical equilibrium. 



Since my investigation concerns in the first instance com- 

 plete equilibrium, the velocity of reaction before complete 

 equilibrium, &c, I would first recapitulate some of the results 

 of his work with which the present paper is connected. 



Gibbs gives us " the criterion of equilibrium and stability " 

 thus : — " For the equilibrium of any isolated system it is 

 necessary and sufficient that in all possible variations in the 

 state of the system, which do not alter its entropy, the 

 variation of its energy shall either vanish or be positive, i. e. 

 (& e )ri =9" where e denotes the energy and tj the entropy of 

 the system. Equivalent to this is the theorem that {Br}) e ^0 

 * Communicated by the Author. 



