NOMOS. 



41 



that they issue in the re-arrangement of all the inter- 

 vening elements into new molecules. 



Fig. 3. 



Fig. 4. 



In order to understand the next change we must 

 have recourse to another diagram. The change is 

 this. The negative element hydrogen tends, we 

 have said, to unite with the positive element of the 

 platinum molecule next to it, but it only tends. The 

 affinities between the metal and gas are not strong 

 enough to secure union, and the primary result is, 

 that the hydrogen escapes as gas, a fact which we 

 indicate in the following diagrams by placing its 

 symbol above the line, with an arrow to indicate this 

 upward tendency. Escaping in this way, the hy- 

 drogen liberates the positive platinum element, with 

 which it had tended to unite, and this element acting 

 upon the contiguous molecule, initiates a series of 

 decompositions and re-combinations which traverses 

 the rest of the circuit, and ends in the restoration of 

 all the molecules to the condition in which they were 



