Electricity is developed by motion, by friction, and by almost every change that takes place.
Is electricity found in the air?
Yes; the air is almost constantly electrified.
With what is electricity often accompanied?
Electricity is often accompanied by heat and light.
How many kinds of electricity are there?
There are two kinds of electricity.
What are they called?
They are called positive and negative electricity.
What do these two kinds of electricity always do?