and left the lounge.  Ten minutes later he passed through the outer hall, the woman beside him, and the pair of them, wrapped up in cloak and ulster, went out into the night.  At the door, Vance turned and threw a quick, investigating glance in his direction.  There seemed a hint of questioning in that glance; it might almost have been a tentative invitation.  But, also, he wanted to see if their exit had been particularly noticed—­and by whom.

This, briefly told, was the first manoeuvre by which Fate introduced them.  There was nothing in it.  The details were so insignificant, so slight the conversation, so meagre the pieces thus added to Henriot’s imaginative structure.  Yet they somehow built it up and made it solid; the outline in his mind began to stand foursquare.  That writing, those designs, the manner of the man, their going out together, the final curious look—­each and all betrayed points of a hidden thing.  Subconsciously he was excavating their buried purposes.  The sand was shifting.  The concentration of his mind incessantly upon them removed it grain by grain and speck by speck.  Tips of the smothered thing emerged.  Presently a subsidence would follow with a rush and light would blaze upon its skeleton.  He felt it stirring underneath his feet—­this flowing movement of light, dry, heaped-up sand.  It was always—­sand.

Then other incidents of a similar kind came about, clearing the way to a natural acquaintanceship.  Henriot watched the process with amusement, yet with another feeling too that was only a little less than anxiety.  A keen observer, no detail escaped him; he saw the forces of their lives draw closer.  It made him think of the devices of young people who desire to know one another, yet cannot get a proper introduction.  Fate condescended to such little tricks.  They wanted a third person, he began to feel.  A third was necessary to some plan they had on hand, and—­they waited to see if he could fill the place.  This woman, with whom he had yet exchanged no single word, seemed so familiar to him, well known for years.  They weighed and watched him, wondering if he would do.

None of the devices were too obviously used, but at length Henriot picked up so many forgotten articles, and heard so many significant phrases, casually let fall, that he began to feel like the villain in a machine-made play, where the hero for ever drops clues his enemy is intended to discover.

Introduction followed inevitably.  “My aunt can tell you; she knows Arabic perfectly.”  He had been discussing the meaning of some local name or other with a neighbour after dinner, and Vance had joined them.  The neighbour moved away; these two were left standing alone, and he accepted a cigarette from the other’s case.  There was a rustle of skirts behind them.  “Here she comes,” said Vance; “you will let me introduce you.”  He did not ask for Henriot’s name; he had already taken the trouble to find it out—­another little betrayal, and another clue.