tharkay said impatiently , flinging back the trap-door , and led the way down , down ; down rotted stairs into a cellar of bare earth , very damp , and far in the back yet another door : or rather a doorway , so low laurence had nearly to bend double to get through it , and leading further below were steps hewn not of wood but stone , round-edged and slimy with age ; up from the deep dark came the soft plucking sound of dripping water .