"I found nothing." "Nothing ?" said the Duke.
"No.

Are you sure you saw the handkerchief in one of those little rooms on the second floor--quite sure ?" said Guerchard.
"Of course I did," said the Duke.

"Isn't it there ?" "No," said Guerchard.
"You can't have looked properly," said the Duke, with a touch of irony in his voice.

"If I were you, I should go back and look again." "No.

If I've looked for a thing, I've looked for it.