"You know exactly how all of them work, then?"
He saw where I was heading. "Most of them," he hedged.
Thursby saw where I was heading, too, and was sweating. I'd managed to get around his objection.
"Have you ever examined any which you could not understand?"
"I ... I don't quite know what you mean."
"Have you ever," I said firmly, "come across a device used in cheating which you could not comprehend or explain the operation of?"
Thursby stood up. "Same objection as before, Your Honor."
"Your Honor," I said, "I am merely trying to find the limitations of the witness' knowledge; I am not trying to refute his acknowledged ability."
"Overruled," said Judge Lapworth. "The witness will answer the question."
I repeated the question.