The luminous dial activates it. Here, hold this.
5 seconds sound clip from the Dr. No movie soundboard.
You can hear this line at 00:46:48 in the Blu-ray version of the movie.
Quote context
[...]
- Forget it. I'm sure it's not very important anyhow.
- I'd just hate to think you're gonna spend the whole afternoon looking for these things.
- No. I have the afternoon off.
- There's a coincidence. So have I. Why don't you show me around the island?
- What should I say to an invitation from a strange gentleman?
- Good.
- The luminous dial activates it. Here, hold this.
- Now, where exactly did Commander Strangways place those samples?- About where your feet is, sir.
- Good.
- Hi.
- Take a look at this Geiger reading.
[...]