NOMOS. 31 



nothing to do with this result, for so far as the 

 oxygen is concerned (and the oxygen may illustrate 

 the general fact) the amount is absolutely the same 

 when it is given off in the cell of the battery, and 

 combines with the zinc of that cell, or whether it is 

 given off in the glass in which the platinum electrode 

 is plunged, and with which electrode it cannot com- 

 bine. The experiment shows, moreover, not only 

 that the electricity originates in the chemical changes 

 within the cells of the battery, but that the current 

 itself is attended by these changes whenever the 

 current has to pass through a fluid. It even seems 

 to hint that chemical changes may be as necessary to 

 the conduction as to the origination of the current. 



But what of the other parts of the circuit ? What 

 is the condition of the metals which form part of the 

 circuit ? In what state is the air when the current 

 passes through it ? Are these the seat of any defi- 

 nite changes such as are found in the fluids ? 



The condition of the metallic parts of the circuit 

 is one of great obscurity ; but, thanks to the present 

 illustrious Master of the Mint, the ob- 

 scurity is not altogether without light. 

 Now Prof. Graham holds " that the ulti- 



mate atoms of a metallic mass are under e " a i" ic the 

 the influence of chemical affinities, being parts of the 



circuit. 



in a state of chemical combination one 

 with another, and not isolated and independent of 

 one another, like loose grains of sand." He believes 

 that metals are composed of molecules, or groups of 

 three atoms, either two of which three atoms may 

 combine to form an element whose properties, as com- 



