Balance scale and bellows: what they have in common

1. Step 1. Balance scale — is made of — Stone. Weights were hewn from stone.
2. Step 2. Stone — is material for — Blast furnace. The shaft of a blast furnace is stone.
3. Step 3. Blast furnace — has part — Bellows. Air was blown in by bellows, later by blowers.

Open Evothings