314 THE INTELLECTUAL RISE IN ELECTRICITY. 



verticity of the compass-needle ; to discover magnetic 

 screening, conduction and saturation, the compound mag- 

 net, the mutual attraction or induction of lodestone and 

 iron, the pole-piece or armature, the effect of induction on 

 soft iron, and magnetization by molecular disturbance ; and 

 to discover electrical charge and its permanence for a con- 

 siderable period of time, and that it can be retained by 

 covering the excited body with certain substances. He 

 invented the first electrical (as distinguished from mag- 

 netic) instrument, the first electrical indicating device, the 

 first magnetometer, filar suspension, and the ordinary 

 method of magnetization. 



