80 FARADAY 



What is this? It is the same thing which you saw when 

 I discharged the large electrical machine, when you saw one 

 single bright flash ; it is the same thing, only continued, be- 

 cause here we have a more effective arrangement. Instead 

 of having a machine which we are obliged to turn for a long 

 time together, we have here a 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 intro- 

 duced 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 combustion 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 burning in those 

 cells, and that this is the light of that burning [bringing 

 the two poles in contact and showing the electric light] ; 

 and we might so arrange our apparatus as to show that 

 the amounts of power evolved in either case are identical. 

 Having thus obtained power over the chemical force, how 

 wonderfully we are able to convey it from place to place! 

 When we use gunpowder for explosive purposes, we can 

 send into the mine chemical affinity by means of this elec- 

 tricity; not having provided fire beforehand, we can send 

 it in at the moment we require it. Now here (FiG. 47) is 

 a vessel containing two charcoal points, and I bring it 

 forward as an illustration of the wonderful power of con- 

 veying this force from place to place. I have merely to 

 , connect these by means of wires to the opposite ends of the 



