XVI
Let me now explain the difference between the flash and the bolt of lightning which you naturally wish to know. The flash is the fire widely spread out, the bolt is the condensed fire hurled with violence. Let me use a homely illustration. We sometimes join our two hands in order to take up water in them; then we squeeze our palms together and squirt out the water like a syringe. Imagine something like this to take place in the clouds. When they are compressed the restricted space drives out the air between them, setting it on fire at the same time, and hurling it forth like a cannon ball. The missiles from our balistae44 and scorpions44 give forth a loud noise as they are hurled.