68 THERMO-ELECTRICITY. 



CHAPTER X. 



CONVERTIBILITY OF VIBRATIONS OF HEAT INTO 

 ELECTRIC CURRENTS. 



n^HE vibrations of the electric ether, consti- 

 tuting heat, are readily converted into a 

 current in one determinate direction through the 

 circuit of a conducting wire, so as to turn the 

 needle of a galvanometer, by merely arranging in 

 contact the ends of two bars of metal, one of 

 them a good electrode, and the other a less free 



Fig- ii. 



electrode, over the flame of a lamp ; as represented 

 in Fig. ii. The vibratory movements of the 

 ether become resolved into one uniform direction 

 through the most ready conductor, so as to make 

 a closed circuit; as denoted by the direction of 

 the arrows. The excitation of the current being 

 caused by heat, the descriptive name of Thermo- 

 electricity has been given to this mode of pro- 



