Read this extract, and then answer the question that follows it: 'I gave in the cheque myself, and said I had every reason to believe it was a forgery. Not a bit of it. The cheque was genuine.' 'Tut-tut!' said Mr Utterson. 'I see you feel as I do,' said Mr Enfield. ‘Yes, it's a bad story. For my man was a fellow that nobody could have to do with, a really damnable man; and the person that drew the cheque is the very pink of the proprieties, celebrated too, and (what makes it worse) one of your fellows who do what they call good. Blackmail, I suppose; an honest man paying through the nose for some of the capers of his youth. Blackmail House is what I call that place with the door, in consequence. Though even that, you know, is far from explaining all,' he added; and with the words fell into a vein of musing. From this he was recalled by Mr Utterson asking rather suddenly: 'And you don't know if the drawer of the cheque lives there?' 'A likely place, isn't it?' returned Mr Enfield. 'But I happen to have noticed his address; he lives in some square or other.' 'And you never asked about – the place with the door?' said Mr Utterson. 'No, sir: I had a delicacy,' was the reply. ‘I feel very strongly about putting questions; it partakes too much of the style of the day of judgment. You start a question, and it's like starting a stone. You sit quietly on the top of a hill; and away the stone goes, starting others; and presently some bland old bird (the last you would have thought of) is knocked on the head in his own back garden, and the family have to change their name. No, sir, I make it a rule of mine: the more it looks like Queer Street, the less I ask.' 'A very good rule, too,' said the lawyer. 'But I have studied the place for myself,' continued Mr Enfield. 'It seems scarcely a house. There is no other door, and nobody goes in or out of that one, but, once in a great while, the gentleman of my adventure. There are three windows looking on the court on the first floor; none below; the windows are always shut, but they're clean. And then there is a chimney, which is generally smoking; so somebody must live there. And yet it's not so sure; for the buildings are so packed together about that court, that it's hard to say where one ends and another begins.' The pair walked on again for a while in silence; and then – 'Enfield,' said Mr Utterson, 'that's a good rule of yours.' 'Yes, I think it is,' returned Enfield. 'But for all that,' continued the lawyer, ‘there's one point I want to ask: I want to ask the name of that man who walked over the child.' 'Well,' said Mr Enfield, ‘I can't see what harm it would do. It was a man of the name of Hyde.' 'Hm,' said Mr Utterson. 'What sort of a man is he to see?' 'He is not easy to describe. There is something wrong with his appearance; something displeasing, something downright detestable. I never saw a man I so disliked, and yet I scarce know why. He must be deformed somewhere; he gives a strong feeling of deformity, although I couldn't specify the point. He's an extraordinary-looking man, and yet I really can name nothing out of the way. No, sir; I can make no hand of it; I can't describe him. And it's not want of memory; for I declare I can see him this moment.' Mr Utterson again walked some way in silence, and obviously under a weight of consideration. ‘You are sure he used a key?' he inquired at last. 'My dear sir ...' began Enfield, surprised out of himself. 'Yes, I know,' said Utterson; 'I know it must seem strange. The fact is, if I do not ask you the name of the other party, it is because I know it already. You see, Richard, your tale has gone home. If you have been inexact in any point, you had better correct it.' 'I think you might have warned me,' returned the other, with a touch of sullenness. 'But I have been pedantically exact, as you call it. The fellow had a key; and, what's more, he has it still. I saw him use it, not a week ago.' Mr Utterson sighed deeply, but said never a word; and the young man presently resumed. ‘Here is another lesson to say nothing,' said he. ‘I am ashamed of my long tongue. Let us make a bargain never to refer to this again.' 'With all my heart,' said the lawyer. ‘I shake hands on that, Richard.' [from Chapter 1, ‘Story of the Door’] How does Stevenson create a sense of mystery at this early moment in the novel?