: At the market, Li Wei watched a merchant exchange a lightweight slip of paper for a crate of silk. This "flying money" was much easier to carry than heavy bags of copper coins. 2. The Social Ladder
Ancient China for Kids: Inventions and Technology - Ducksters srednevekovyi kitai referat 6 klass
: His father checked a small device in a bowl of water—an "iron fish" or compass —to ensure they were heading exactly south toward the market gates. : At the market, Li Wei watched a