Mercedes grew thinner, until she was a slender shadow of her former self.  She became hard, brown as the rangers, lithe and quick as a panther.  She seemed to live on water and the air—­perhaps, indeed, on love.  For of the scant fare, the best of which was continually urged upon her, she partook but little.  She reminded Gale of a wild brown creature, free as the wind on the lava slopes.  Yet, despite the great change, her beauty remained undiminished.  Her eyes, seeming so much larger now in her small face, were great black, starry gulfs.  She was the life of that camp.  Her smiles, her rapid speech, her low laughter, her quick movements, her playful moods with the rangers, the dark and passionate glance, which rested so often on her lover, the whispers in the dusk as hand in hand they paced the campfire beat—­these helped Gale to retain his loosening hold on reality, to resist the lure of a strange beckoning life where a man stood free in the golden open, where emotion was not, nor trouble, nor sickness, nor anything but the savage’s rest and sleep and action and dream.

Although the Yaqui was as his shadow, Gale reached a point when he seemed to wander alone at twilight, in the night, at dawn.  Far down the arroyo, in the deepening red twilight, when the heat rolled away on slow-dying wind, Blanco Sol raised his splendid head and whistled for his master.  Gale reproached himself for neglect of the noble horse.  Blanco Sol was always the same.  He loved four things—­his master, a long drink of cool water, to graze at will, and to run.  Time and place, Gale thought, meant little to Sol if he could have those four things.  Gale put his arm over the great arched neck and laid his cheek against the long white mane, and then even as he stood there forgot the horse.  What was the dull, red-tinged, horizon-wide mantle creeping up the slope?  Through it the copper sun glowed, paled, died.  Was it only twilight?  Was it gloom?  If he thought about it he had a feeling that it was the herald of night and the night must be a vigil, and that made him tremble.

At night he had formed a habit of climbing up the lava slope as far as the smooth trail extended, and there on a promontory he paced to and fro, and watched the stars, and sat stone-still for hours looking down at the vast void with its moving, changing shadows.  From that promontory he gazed up at a velvet-blue sky, deep and dark, bright with millions of cold, distant, blinking stars, and he grasped a little of the meaning of infinitude.  He gazed down into the shadows, which, black as they were and impenetrable, yet have a conception of immeasurable space.

Then the silence!  He was dumb, he was awed, he bowed his head, he trembled, he marveled at the desert silence.  It was the one thing always present.  Even when the wind roared there seemed to be silence.  But at night, in this lava world of ashes and canker, he waited for this terrible strangeness of nature to come to him with the secret.  He seemed at once a little child and a strong man, and something very old.  What tortured him was the incomprehensibility that the vaster the space the greater the silence!  At one moment Gale felt there was only death here, and that was the secret; at another he heard the slow beat of a mighty heart.