582. Why do these phenomena produce electricity?
Because they disturb the equilibrium of the electric force, and produce positive and negative states of electricity.
583. When does lightning occur?
When clouds, charged with the opposite electricities approach, the forces rush to each other, and combine in a state of equilibrium.
584. Why does lightning attend this movement of the forces of electricity?
Because the atmosphere, being unable to convey the great charges of electricity as they rush towards each other, acts as an insulator, and lightning is caused by the violence of the electricity in forcing its passage.
585. Does lightning ever occur when the conducting power is equal to the force of the electricity?
No; electricity passes invisibly, noiselessly, and harmlessly, whenever it finds a sufficient source of conduction.