Screw casing tube and gas lamp: what they have in common

1. Step 1. Screw casing tube — is part of — Archimedes’ screw. It wraps around the blade.
2. Step 2. Archimedes’ screw — evolved into — Propeller. The first propellers by Smith and Ericsson were a variation on the Archimedes’ screw.
3. Step 3. Propeller — is part of — Airship. Air propellers.
4. Step 4. Airship — evolved from — Hot air balloon. A steerable balloon.
5. Step 5. Hot air balloon — has part — Gas burner. It heats the air in the envelope with a propane flame.
6. Step 6. Gas burner — is part of — Gas lamp. A coal-gas burner.

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