Whenever the cloud contains more electricity than the earth does.
How near are the clouds when the lightning comes to the earth?
The clouds are seldom half a mile away when the lightning comes from them to the earth.
What noise is made by the lightning?
The lightning passes so quickly through the air, that it makes a noise called thunder.
Do we always hear the thunder when there is lightning?
No; the lightning is sometimes so far away that the thunder cannot be heard.
What bodies attract the lightning to the earth?
Tall trees, steeples, high houses, and mountains.
Does the lightning do any harm?