5G8 



THE GOLD-LEAF ELECTROSCOPE. 



charge of the disc ceases, and the negative electricity of 

 the disc becomes also free and escapes through the 

 finger, if still in contact with it; but if the finger is 

 removed before the glass rod, the negative free electri- 

 city of the disc cannot escape, and the disc is charged 

 with free negative electricity, when the glass rod is 

 removed. This state is indicated in C, fig. 306. 



Induction plays a most important part in a great 

 many phenomena of electricity. On it depends also 

 the action of the gold-leaf electroscope and of the elec- 

 trophorus. 



The Gold-leaf Electroscope consists essentially of a 

 metal rod terminating at its upper extremity in a knob 



TIG. 307 (A, B, } real size ; C, D, E, real size) 



or a disc and carrying at its lower end two narrow strips 

 of gold-leaf. The lower part of the rod is in the interior 

 of a shade or bottle of glass, as shown in fig. 307, A 

 and .2. 



