426 JSeic Method and Department of Chemical Research. 



a great obstacle to making accurate measurements of such 

 " affinity " by this method is the unmeasured portion of energy 

 lost by u local action." It may be further remarked that, 

 disregarding "local action/' this chemical union and neutrali- 

 zation of opposite molecular motions only occurs whilst the 

 circuit is closed ; and that at the instant of closing the circuit, 

 potential energy is converted into kinetic energy, and a multi- 

 tude of electromagnetic waves of very varied lengths are 

 generated and radiated into space : the conversion of energy, 

 therefore, in this kind of case depends upon closing of the 

 circuit. 



The results obtained by varying the strength or the tempe- 

 rature of the liquid at each metal separately support the con- 

 clusion that, in an ordinary voltaic cell, nearly the whole of the 

 energy is due to action at the zinc, and but little to that at the 

 platinum ; and that the latter acts nearly wholly by obviating 

 the greater counter electromotive force which would occur by 

 using a more corrodible metal, and by diminishing the resist- 

 ance which a less conducting substance would offer. The 

 mere absence of an obstacle to a change cannot be an active 

 cause of that change ; and any substance which takes an 

 essential part in any physical or chemical action, and (like 

 the platinum plate) remains exactly the same in every respect 

 after the action as it was immediately previous to it, cannot 

 have been a real cause of that action, or of any loss or gain of 

 energy attending it. The presence of the negative metal is 

 only a static permitting condition ; it enables, without any 

 expenditure of energy on its own part, the opposite potential 

 molecular motions of the positive metal and the liquid to 

 neutralize each other and to be converted into voltaic current. 



The method described in this paper is not merely a technical 

 one of detecting substances, nor is it specially fitted for such 

 a purpose ; but it is an extensive new department of chemical 

 and molecular research, and a general system of representation 

 by means of geometrical curves, not only of individual sub- 

 stances, but of some of the fundamental changes of molecular 

 motion of substances which are inseparably related to their 

 chief chemical properties ; and it will in this way supply 

 mathematicians with a new and extensive series of facts, 

 representing, in terms of electromotive force, the degrees of 

 volta-chemical action of metals and electrolytes upon each 

 other. One of the chief uses of it as a method of research 

 will be to examine the molecular structure and chemical com- 

 position of dissolved substances, to detect differences and 

 changes in them caused by heat, light, chemical union, sub- 

 stitution, or decomposition, (fee. ; and to detect and measure 



