252 Mr. Smee's New Definition of the Voltaic Circuit, 



and all the resistances are supposed to be constant. In some 

 cases we might be desirous of ascertaining the values of the 

 other parts of the circle ; thus if we desired to find the affinity 

 (F) F = I + a + c + r + e, — the conducting power of the con- 

 necting part of the arrangement (c)c= F — l + a + r + e. The 

 removal of the newly found compound (a) a=F — L+c + r + e, 

 the resistance offered by the compound fluid (r) r = F 

 — l + a+c + e, the resistance to the removal of the second 

 element of the compound e = F— I + a + c + r. 



Sometimes this circle is exceedingly small, the (r) consist- 

 ing of but one atom of the compound, and (c) but of a 

 single atom of the body combining with one element. This 

 might be properly called an atomic circle, a good specimen of 

 which has heretofore been called local action. 



We must now consider the different parts of the circle in 

 detail ; and now a question naturally arises whether the inter- 

 vening compound may consist of any number of elements, or 

 whether it is essential that the compound should be made up of 

 only two elements. From a consideration of the voluminous 

 experiments of our great authority Faraday, it would appear 

 probable that the second hypothesis is correct, although it 

 is just possible that if the body consists of more than two ele- 

 ments, that the impediment to the evolution of the other ele- 

 ments (e) or the resistance of the fluid part (r) become so enor- 

 mously increased as to stop any (F) or series of (F) that we 

 have ever applied. Another question also arises, as to whether 

 compound must necessarily be a fluid which requires the same 

 consideration as the first question. 



(F) the chemical affinity of a body for one element of a com- 

 pound is immensely strong where zinc is employed, the at- 

 traction of that metal for oxygen being most powerful ; but 

 if we substitute iron, tin, lead, copper, or gold, for the zinc, 

 the attraction being feeble, the value of (F) would be reduced 

 in various proportions, in some cases almost to zero. 



(a) the removal of the newly-formed compound affords but 

 little resistance when the new salt is soluble in the fluid and a 

 sufficiency is supplied for that purpose. In batteries gene- 

 rally the removal of sulphate of zinc affords but little obstacle, 

 being quickly dissolved by water ; (a) in some cases is the 

 removal of the first element of the compound by evolution, 

 thus in the voltameter oxygen is evolved. In these cases (a) is 

 very large, and offers great obstacles to the passage of the cur- 

 rent. The removal of the first element is sometimes accom- 

 plished by decomposition ; thus oxygen may be removed by 

 hydriodic acid, by the decomposition of which body (a) is di- 



