CHAP, i.] -ELECTRICITY AND MAGNETISM. 19 



and hold it near to a body that has not been electrified, 

 what will occur ? We take for this experiment the 

 apparatus shown in Fig. 10, consisting of a long 

 sausage -shaped piece of metal, either hollow or solid, 

 held upon a glass support. This " conductor," so called 

 because it is made of metal which permits electricity to 

 pass freely through it or over its surface, is supported on 

 glass to prevent the escape of electricity to the earth, 

 glass being a non-conductor. The presence of the 

 positive electricity of the glass ball near this conductor 

 is found to indttce electricity on the conductor, which, 



Fig. 10. 



although it has not been rubbed itself, will be found to 

 behave at its two ends as an electrified body. The 

 ends of the conductor will attract little bits of paper ; 

 and if pairs of pith-balls be hung to the ends they are 

 found to diverge. It wift, however, be found that the 

 middle region of the long-shaped conductor will give no 

 sign of any electrification. Further examination will 

 show that the two electricities on the ends of the con- 

 ductor are of opposite kinds, that nearest the excited 

 glass ball being negative electricity, and that at the 

 farthest end being an equal quantity of positive elec- 



