Marco Polo had many wonderful stories to Tell when he came home to Venice from China More than 600 years ago.One of his stories was that.
The Chinese used a kind of black rock as fuel.Not many people believed him.Whoever heard of burning rock？ Bur mow so much.
Whoever black rock is burned that it keeps thousands of people busy digging it out of the ground.The black rock, of course, is coal.
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