And so, by merely pressing a button, the operator can destroy the target even though it's thousands of miles away.
6 seconds sound clip from Superman (1948) - The Reducer Ray (Chapter 3).
You can hear this line at 00:08:09.860 in the Blu-ray version of the episode.
Quote context
[...]
- Will you step over here, Superman?
- That is, if you're free to say.
- Why, I think it's safe to tell you. Dr. Graham, will you explain, please?
- The machine, from then on, makes its own calculations.
- Have all arrangements for the test been completed, doctor?
- A concrete block house has been built in the Western dessert, miles from any habitation.
- I'd like you to see that test, Superman.
- Hm. That's about 2000 miles away. I can be there in 30 seconds.
[...]