The black gentleman

In chapter 35, Mr Weston comes late to the party and tells everyone his son, Frank Churchill, is coming back soon:

'Well, he is coming, you see; good news, I think. Well, what do you say to it? - I always told you he would be here again soon, did I not? Anne, my dear, did not I always tell you so? In town next week, you see - at the latest, I dare say, for she is impatient as the black gentleman when anything is to be done; most likely they will be there tomorrow or Saturday."


Who is the black gentleman? The devil I suppose. It is not a phrase I have come across before. I could google it, but where's the fun in that.

Interestingly, there is a reference to slavery and its abolition in that chapter. Mrs Elton says one of her friends, Mr Suckling was a friend to the abolition. I notice Emma was published in 1816. Wikipedia says the UK introduced a law abolish the slave trade in 1806, although slavery was abolished throughout the empire until 1833.

It must mean the devil, but I've not come across the phrase.