| Answer | Crossword Clue |
|---|---|
| NEON | Gas in a tube |
| ARGON | Gas in a vacuum tube |
| ANODE | ... ray (stream of positive ions in a gas-discharge tube) |
| NEON | Tube gas |
| ARGON | Tube gas |
| XENON | Tube gas |
| XENON | Radio-tube gas |
| XENON | Radio tube gas |
| ARGON | Vacuum tube gas |
| ARGON | Fluorescent tube gas |
| NEON | Light-tube gas |
| ARGON | Vacuum-tube gas |
| ARGON | Radio-tube gas |
| NEON | Glow tube gas. |
| NEON | Glow-tube gas. |
| ARGON | Radio tube gas. |
| ARGON | Radio tube gas |
