142 CORRELATION OF THE PHYSICAL FORCES. 



stops. Here is a better instance to enable some 

 of you to see the certainty with which we can 

 convey this force, where, under ordinary cir- 

 cumstances, chemical affinity would not act. 

 We may absolutely take these two charcoal 

 poles down under water, and get our electric 

 light there; there they are in the water, and 

 you observe when I bring them into connection 

 we have the same light as we had in that glass 

 vessel. 



Now, besides this production of light we have 

 all the other effects and powers of burning zinc. 

 I have a few wires here which are not combus- 

 tible, and I am going to take one of them, a 

 small platinum wire, and suspend it between 



Fig. 48. 



these two rods which are connected with the 

 battery, and when contact is made at the bat- 



