ELECTRICITY. 85 



polar; it is the electricity of fire represented in oxygen. 

 The _ E is the weaker, that which has only been evoked, 

 the basic ; it is the electricity of the planet represented in 

 nitrogen, hydrogen, carbon, sulphur. It may be said 

 that E is related to + E as planet is to sun, as 

 periphery to centre. The sun is + E, the planet E, 

 the one the electricity of oxygen, the other of hydrogen. 



419. These electrical conditions must always be chang- 

 ing in the air, according as the slightest influence is 

 brought to bear upon them from without. The air con- 

 sists in this change of electrical poles. Were the poles 

 not to change, the air would be a solid element. The 

 earth is an air vfii\\ fixed electricity, the water with ex- 

 tinguished or neutralized electricity. 



420. The twofold character of the aerial principles is 

 increased by every polarizing action from without, and 

 therefore principally by the surface of the earth, which 

 consists of two elements. Were there no surface to the 

 earth, were simply air present, then there would be no 

 electrical change of poles, The surface of the earth itself, 

 however, produces no change of poles in the air, for it 

 remains always neutral ; but it becomes unequal or polar 

 from the change wrought upon it by water and earth, by 

 light, by heating and by chemical processes. 



421. The air also changes the electricities while it 

 roams over the earth. This wandering motion is a con- 

 tact of differently polarized tracts of the earth. Every 

 mountain, valley, and river, every meadow is differently 

 polarized ; from each the air derives another electricity. 

 Through this ceaseless alternation of polar exchange, its 

 activity becomes so elevated that at last the electricity 

 makes its appearance in a manner cognizable by the 

 senses. The production of electricity by friction admits 

 of a similar explanation. Eriction is in miniature, what 

 the sweeping of air is over the earth. Were the earth 

 quite level, and composed of homogeneous matter, the 

 air would not become electric by motion. 



422. All terrestrial electricity has been evoked by a 

 change of poles analogous to friction. Through light 



