| Answer | Crossword Clue |
|---|---|
| NEON | Inert gas in vacuum tubes |
| ARGON | Inert gas used in vacuum tubes |
| NEON | Element in vacuum tubes |
| ANODES | Positive poles in vacuum tubes. |
| XENON | Inert gas used in lights |
| ARGON | Inert gas used in welding |
| ARGON | Common inert gas in the atmosphere |
| ARGON | Most common inert gas in the atmosphere |
| INDEXXENON | List an inert gas in the correct directory? |
