But there was no great difficulty in the first stage of my adventure. Upper Swandam Lane is a vile alley lurking behind the high wharves which line the north side of the river to the east of London Bridge. Between a slop-shop and a gin-shop, approached by a steep flight of steps leading down to a black gap like the mouth of a cave, I found the den of which I was in search. Ordering my cab to wait, I passed down the steps, worn hollow in the centre by the ceaseless tread of drunken feet; and by the light of a flickering oil-lamp above the door I found the latch and made my way into a long, low room, thick and heavy with the brown opium smoke, and terraced with wooden berths, like the forecastle of an emigrant ship.