You think? That's mate... old chum.
6 seconds sound clip from Batman (1966) - A Riddle a Day Keeps the Riddler Away (S1E11) TV Series.
You can hear this line at 00:02:48 in the Blu-ray version of the movie.
Quote context
[...]
- Anyone else think they can make any sense out of it? Well, there is one man who might be able to.
- I have a fine police force here, yet I have no alternative but to call on his services once again.
- I'll beckon him, sir, immediately.
- You think? That's mate... old chum.
- Gosh, why can't I ever beat you?
- You have on... several occasions.
- Only when your mind is on important matters...
- Excuse me for interrupting, sir. But it's the Batphone.
- Oh, boy!
- Oops! Sorry, Aunt Harriet. I didn't mean to scare you.
- Mercy alive! If I didn't know you two better, I'd think you were up to something.
[...]