Arc lamp and bellows: what they have in common

1. Step 1. Arc lamp — is part of — Street light. The first electric street lights were arc lamps (the “Yablochkov candle”, 1878).
2. Step 2. Street light — evolved from — Gas lamp. Gas lamps.
3. Step 3. Gas lamp — has part — Valve. A gas supply valve.
4. Step 4. Valve — is part of — Bellows. A valve in the bellows lets air in when they open and keeps it from escaping back.

Open Evothings