Side by side with it, his desire to join himself to the purposes of the woman increased steadily. They kept out of his way apparently; the offer seemed withdrawn; he grew restless, unable to settle to anything for long, and once he asked the porter casually if they were leaving the hotel. Lady Statham had been invisible for days, and Vance was somehow never within speaking distance. He heard with relief that they had not gone--but with dread as well. Keen excitement worked in him underground. He slept badly. Like a schoolboy, he waited for the summons to an important examination that involved portentous issues, and contradictory emotions disturbed his peace of mind abominably. VIII But it was not until the end of the week, when Vance approached him with purpose in his eyes and manner, that Henriot knew his fears unfounded, and caught himself trembling with sudden anticipation--because the invitation, so desired yet so dreaded, was actually at hand. Firmly determined to keep caution uppermost, yet he went unresistingly to a secluded corner by the palms where they could talk in privacy. For prudence is of the mind, but desire is of the soul, and while his brain of to-day whispered wariness, voices in his heart of long ago shouted commands that he knew he must obey with joy. It was evening and the stars were out. Helouan, with her fairy twinkling lights, lay silent against the Desert edge. The sand was at the flood. The period of the Encroaching of the Desert was at hand, and the deeps were all astir with movement. But in the windless air was a great peace. A calm of infinite stillness breathed everywhere. The flow of Time, before it rushed away backwards, stopped somewhere between the dust of stars and Desert. The mystery of sand touched every street with its unutterable softness. And Vance began without the smallest circumlocution. His voice was low, in keeping with the scene, but the words dropped with a sharp distinctness into the other's heart like grains of sand that pricked the skin before they smothered him. Caution they smothered instantly; resistance too. "I have a message for you from my aunt," he said, as though he brought an invitation to a picnic. Henriot sat in shadow, but his companion's face was in a patch of light that followed them from the windows of the central hall. There was a shining in the light blue eyes that betrayed the excitement his quiet manner concealed. "We are going--the day after to-morrow--to spend the night in the Desert; she wondered if, perhaps, you would care to join us?" "For your experiment?" asked Henriot bluntly. Vance smiled with his lips, holding his eyes steady, though unable to suppress the gleam that flashed in them and was gone so swiftly. There was a hint of shrugging his shoulders.