38 NOMOS. 



decomposed molecule of hydrochloric acid, decom- 

 poses it, forms a new molecule of this acid by uniting 

 with the chlorine, and liberates another element of 

 hydrogen in its place. This second element of hy- 

 drogen, thus liberated, having no chlorine element 

 with which to unite, seeks to satisfy its affinities 

 upon the positive element of the platinum molecule, 

 which is next to it. (This conducts us from the 

 acid to the platinum part of the circuit.) These 

 affinities draw the hydrogen and platinum element 

 together, not close enough to produce union, but 

 close enough to liberate the positive element of the 

 platinum molecule from the negative element with 

 which it was formerly united, and then this negative 

 element is left free to act upon the molecules beyond. 

 Free to act in this way, it decomposes the next 

 platinum molecule, forms a new molecule by uniting 

 with the liberated positive element, and liberates 

 the negative element. This latter element having 

 no proper mate (for we are now brought to the 

 upper part of the circuit), endeavours to get one 

 from the adjacent copper molecule, and its attrac- 

 tions, though not sufficient to produce union, are 

 sufficient to liberate the positive element with which 

 it was formerly united. This liberates a negative 

 copper element, and this element immediately de- 

 composes the next copper molecule, giving rise to 

 a new molecule by uniting with the liberated posi- 

 tive element, and liberating the negative element. 

 This liberated negative element of the last copper 

 molecule acts upon the contiguous zinc molecule, 

 as the negative platinum element did upon the con- 



