The forest, though in the windless calm not a leaf fluttered, was full of disquieting noises. There were rustlings, faint, half perceptible crackings of twigs, dull, muffled, resistant sounds from the earth which must surely be caused by human footfall. Once his whole frame sprung into startled alertness as a night bird shrieked in the cork branches not twenty yards away. The faint but distinct after-echo of a chorussed sigh told him how a dozen other pulses had leaped with his. The quick, irregular darting run of a small animal--a jerboa or a forest rat--produced a little less disturbing effect. But the soft, stolid breathing of his horse, as its breath beat past his shoulder, was a soothing, soporific sound which his nerves welcomed, yet seemed to protest against as tending to lull him into an unalert insecurity. With a sudden qualm of reproach he found his head dropping sideways and smiting lightly the trunk of the palm. He drew himself up with a quick, decisive tautening of his muscles. He would not sleep; his eyelids almost ached with the intensity with which he held them apart. Sleep, like fate, is a tricky jade to defy. It was Perinaud's voice, level and stolid, but with a faint note of sarcasm, which aroused him. "Monsieur may now sleep in comfort if he will," suggested the sergeant. "There is little fear from surprise with such a moon." Aylmer blinked. The round white orb was sending its rays in full flood through the broad fans of the palm leaves overhead. It tinged the cork trees with silver radiance; it produced an effect of grateful coolness in the cinder-dry thickets and powdery earth. It was as if dew had fallen, a dew of light. And the shadows of the gorge were of a velvet blackness in contrast. Aylmer looked carefully round. It was as Perinaud said. The forest spaces were clear; one could trace them almost as distinctly as in the daylight. No enemy could steal upon them unseen. And so it was with a little sigh of content that he laid his head back upon his saddle, pulled his cloak more disposedly about him, and prepared to give nature freely what during the past three hours she had stolen. With the usual result. Sleep deserted him. He closed his eyes resolutely; he breathed with exact precision; he even counted an imaginary flock of sheep as they passed sedately between two supposititious hurdles. He remained broadly awake, his eyes rebelling against their imprisonment till at last he gave up trying to coerce them. He searched his pocket, found tobacco and a pipe, and smoked. His brain became suddenly active.