"I was only joking, Colonel," he said, with a forced laugh.
"I'm glad to hear it.

But as this joke is in black and white, you wouldn't mind saying so in the same fashion.

Take that pen and ink and write as I dictate.

'I certify that I am satisfied that the above statement is a base calumny against the characters of Ringwood Clinch, Robert Rawlins, and John Hale, passengers, and that I do hereby apologize to the same.' Sign it.

That'll do.