52 ELEMENTS OF STATIC ELECTRICITY. 



To illustrate : Suppose we have two insulated metal 

 plates, A and B (Fig. 7j, separated by an air space C ' ; 

 let A be electrified and J9. connected with the disc of 

 an electroscope. First note the amount of divergence 

 of the leaves ; then let a plate of glass, cake of paraffin, 

 or any other insulator which will exactly fill the space 



Fig. 7 Specific Inductive Capacity Illustrated. 



(7, be introduced between the plates, and note the diver- 

 gence of the leaves now, as compared with the former 

 divergence. 



As this insulator has displaced the air, it is evident 

 that its inductive capacity, as compared with air, is 

 shown by the difference in the divergence of the leaves. 



