midnight
And then , for the first time , he discovered that the man had brought a faint , elusive suggestion of perfume with him , an aromatic odour , that made him think of priests and churches . The ghost of it still lingered in the air . Ah , here then was the origin of the notion that his voice had chanted : it was surely the suggestion of incense . But incense , intoning , a compass to find the true north -- at midnight in a Desert hotel ! A touch of uneasiness ran through the curiosity and excitement that he felt . And he undressed for bed . `` Confound my old imagination , '' he thought , `` what tricks it plays me !