'I don't know,' Henry said expectantly.

'Guess,' Mark Snyder commanded him.

But Henry would not guess, and Snyder rang the bell for Geraldine.

'Miss Foster,' he addressed the puzzling creature in a casual tone, 'did you draw that cheque for Mr. Knight?'

'Yes, Mr. Snyder.'

'Bring it me, please.'

And she respectfully brought in a cheque, which Mr. Snyder signed.

'There!' said he, handing it to Henry. 'What do you think of that?'

It was a cheque for one thousand and eighty pounds. Gordon and Brothers, the greatest publishing firm of the United States, had paid six thousand dollars for the right to publish serially A Question of Cubits, and Mark Snyder's well-earned commission on the transaction amounted to six hundred dollars.