At the mention of the Duke of Monmouth, Eliza began to look Jack in the face again – from which he gathered that one of two things might be the case: either she was looking for a romantic fling with a claim (highly disputable) to the English throne, or else she numbered political intrigues among her interests now. Indeed, when he had surprised her by coming into the Maiden, she'd been writing a letter with her right hand while doing that binary arithmetic on her left, according to the Doctor's practice.