284 MECHANICAL ELECTRICITY. 



the Bismuth. The rod copper was soldered to a 

 wire in connexion with the southern extremity of 

 the galvanometer. 



Exp. 22. By accident the rod copper was torn 

 away, and I applied merely the extremity of the 

 connecting wire against the revolving cylinder. 

 The galvanometer was deflected many degress, 

 and considerably more than hy the friction with 

 the larger surface. A large surface appeared to 

 induce complex results, and to destroy elementary 

 or simple indications. 



Exp. 23. By means of a set screw connected 

 the galvanometer S wire to a turning tool, and 

 slightly turning or shaving oflP ribbons of Bismuth, 

 a considerable current was indicatedyrom the tool 

 towards the Bismuth. This experiment with the 

 Bismuth disc and steel tool was afterwards re- 

 peated by steam power, — current 40 to 45° con- 

 stant, vibrated to 80° or 90° at first. 



Exp. 24. With a Bismuth rod against the Bis- 

 muth cylinder, a current of 4° and afterwards of 

 10° to 15° towards the cylinder was observed.* 



* It is here seen that a preponderance is given in favour 

 of the rod or tool, both metals being alike the rod is positive 

 the disc negative. 



