When the girl raised her calm eyes to his face, the ardent look in his startled her, and she determined to at least listen to any explanation he wished to give her.  “Where have you been, Adrien?” she said gently.  “I thought you had forgotten me.”

“No!” he answered sharply, “that would be impossible; but I was called away.  Do you care for this dance?  Or, would you give me just a few moments with you alone on the terrace?”

Her eyes softened.

“Yes, if you like, Adrien,” she said gently.  “I am really tired now, and longing for the air.”

“Come, then,” he said; and catching up a silken wrap that lay on one of the seats, he threw it tenderly over her.

Together they passed out on to the terrace, and seemed to have slipped into another world, so great a contrast was the peaceful moonlit valley beneath them to the brilliant, heated ball-room they had just left.

As the curtained door swung behind them, Jasper Vermont, alias Mephistopheles—­his scarlet costume now changed to ordinary evening dress, and covered with a long black domino, similar to that which Ada had donned—­shot a sharp glance after them; then, with a sinister smile, he left the room by another exit, and made his way into the grounds.  Keeping well within the shadow of the trees and shrubs, he crouched down, directly under the terrace where Adrien had led Constance; here, motionless and scarcely breathing, he listened with eager ears.

“It is hot,” said Constance, removing her mask, and letting the wrap fall back from her shoulders.

“All the more reason you should be careful,” said Adrien, replacing it gently.

She smiled, as she gazed up at him.

“You look very tired,” she said softly.  “This ball has been a strain on you, has it not?”

“Not more than usual,” he returned.  “At any rate, it will be my last for some time to come.”

“Your last!” she echoed, looking up at him with wide, startled eyes.  “What do you mean, Adrien?”

“I am going away after to-night,” he said hoarsely; for the sight of her beauty was goading him almost to despair.

“Going away!” she hardly breathed the words; her face had paled in the moonlight, till it looked almost unearthly.  “Why?”

“You ask me why?” he murmured, his forehead damp with the force of his emotion.  “You, who know how I love you—­worship your very shadow!”

She trembled under the passion of his gaze.

“Adrien!” she exclaimed, in low, reproachful tones.  “Why do you speak to me like that, when I know how little your words really mean?”

“Little!” he cried with suppressed passion.  “Ah, Constance, why are you so cruel to me?  Why do you so misjudge me, when I would gladly die to serve you?”

The earnestness in his tones was unmistakable; but she kept her face turned from him, and he knew only from the quick-drawn breath that she had heard him.