The Tendencies of Chemistry 



energy, whereas in a cell the same current, 

 produced by the action of the sulphuric acid 

 on the zinc, becomes the residual energy of the 

 reaction, a purely chemical form of energy. 

 It is therefore necessary to abandon all these 

 subtle distinctions, which correspond neither 

 to any theoretical reason, nor any practical 

 criterion. 



When we have once thoroughly grasped the 

 impossibility of separating chemical and physical 

 effects, the study of our facts teaches us that 

 the law of phenomena is more complex than 

 would appear from the principle of maximum 

 work. The comparison of a system in reaction 

 to a falling stone is too simple, the truth is 

 more complicated, and its revelation is a task 

 for the science of energy, the thermo-dynamics 

 of Mayer, Carnot and Clausius. 



This undertaking was first accomplished by 

 one of the greatest physicists of modern times, 

 by Helmholtz, and completed by Gibbs and 

 Duhem. The following comparison is taken 

 from Duhem, an acknowledged master of modern 

 physics : 



" The present data of experimental thermo- 



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