140 CORRELATION OF THE PHYSICAL FORCES. 



chemical power which sends forth the spark 

 and it is wonderful and beautiful to see how 

 this spark is carried about through these wires. 

 I want you to perceive, if possible, that this 

 very spark and the heat it produces (for there 

 is heat), is neither more nor less than the 

 chemical force of the zinc its very force 

 carried along wires and conveyed to this place. 

 I am about to take a portion of the zinc and 

 burn it in oxygen gas for the sake of showing 

 you the kind of light produced by the actual 

 combustion in oxygen gas of some of this 

 metal. [A tassel of zinc-foil was ignited at a 

 spirit-lamp and introduced into a jar of oxygen, 

 when it burnt with a brilliant light.] That 

 shows you what the affinity is when we come 

 to consider it in its energy and power. And 

 the zinc is being burned in the battery behind 

 me at a much more rapid rate than you see in 

 that jar, because the zinc is there dissolving 

 and burning, and produces here this great 

 electric light. That very same power which in 

 that jar you saw evolved from the actual com- 

 bustion of the zinc in oxygen, is carried along 

 these wires and made evident here, and you 

 may if you please consider that the zinc is 



