That's very clever of you, indeed.
4 seconds sound clip from the The Time Machine (1960) movie soundboard.
You can hear this line at 00:07:33 in the Blu-ray version of the movie.
Quote context
[...]
- I've always maintained what this nation needs is a reliable timepiece.
- The Army needs one for the artillery, you know.
- You couldn't do better, George.
- So that's why you've been in hiding?
- That's very clever of you, indeed.
- I don't think George is referring to a new type of timepiece.
- When I speak of time, gentlemen, I'm referring to the fourth dimension.
- Well, the difficulty in explaining the fourth dimension is that it cannot be seen or felt.
[...]

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 Dead of Night (1945)  Phantom of the Opera (1943)
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 Scooby-Doo, Where Are You! (1969)  Halloween III: Season of the Witch (1982)
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