Q. Why does the resistance of the air make the lightning zig-zag?
A. As the lightning condenses the air, in the immediate advance of its path; it keeps flying from side to side, in order to pass where there is the least resistance.
Q. How does lightning condense the air in the immediate advance of its path?
A. The air is condensed by the rapidity of the lightning-flash.
Q. Why is forked lightning more dangerous than a straight flash?
A. Whatever resists the flash, diverts its course; and when terrestrial objects offer resistance to the current, they are in great danger of being destroyed.
Q. Why are there sometimes two flashes of forked lightning at the same moment?
A. Sometimes (in very severe storms) a flash of lightning will divide into two or more parts; and then each branch assumes the zig-zag form.
Q. Why is the flash sometimes quite straight?