midnight
Tradesmen , and the crossing-sweeper at the corner , have caught a glimpse on rare occasions of a white face at the window , the startled face of a queer creature , who blinks and wrings at his nails with his teeth ; who peers at you , jerks and grins ; who seems uncertain what to do ; who sometimes shoots out his hands as if he would drive them through the glass : altogether a mischancy , unaccountable apparition , probably mad . Nobody knows how long he has been here ; for the landlord found him in possession when he bought the lease , and the ground-floor , who was here also , fancies that they came together , but ca n't be sure . There he is , anyhow , and without an open scandal one does n't like to give him notice . A curious thing about the man is that neither landlord nor ground-floor will admit acquaintance with him to each other , although , if the truth were known , each of them knows something -- for each of them has been through his door ; and I will answer for one of them , at least , that he has accompanied the Undesirable upon more than one midnight excursion , and has enjoyed himself enormously . If you could get either of these two alone in a confidential mood you might learn some curious particulars of their coy neighbour ; and not the least curious would be the effect of his changing the glass of the first floor windows . It seems that he had that done directly he got into his rooms , saying that it was impossible to see out of such windows , and that a man must have light . Where he got his glass from , by whom it was fitted , I ca n't tell you , but the effect of it is most extraordinary .