“I know what that is,” exclaimed the dentist.  His eyes searched the ground swiftly until he saw what he expected he should see—­the round thick coil, the slowly waving clover-shaped head and erect whirring tail with its vibrant rattles.

For fully thirty seconds the man and snake remained looking into each other’s eyes.  Then the snake uncoiled and swiftly wound from sight amidst the sagebrush.  McTeague drew breath again, and his eyes once more beheld the illimitable leagues of quivering sand and alkali.

“Good Lord!  What a country!” he exclaimed.  But his voice was trembling as he urged forward the mule once more.

Fiercer and fiercer grew the heat as the afternoon advanced.  At four McTeague stopped again.  He was dripping at every pore, but there was no relief in perspiration.  The very touch of his clothes upon his body was unendurable.  The mule’s ears were drooping and his tongue lolled from his mouth.  The cattle trails seemed to be drawing together toward a common point; perhaps a water hole was near by.

“I’ll have to lay up, sure,” muttered the dentist.  “I ain’t made to travel in such heat as this.”

He drove the mule up into one of the larger canyons and halted in the shadow of a pile of red rock.  After a long search he found water, a few quarts, warm and brackish, at the bottom of a hollow of sunwracked mud; it was little more than enough to water the mule and refill his canteen.  Here he camped, easing the mule of the saddle, and turning him loose to find what nourishment he might.  A few hours later the sun set in a cloudless glory of red and gold, and the heat became by degrees less intolerable.  McTeague cooked his supper, chiefly coffee and bacon, and watched the twilight come on, revelling in the delicious coolness of the evening.  As he spread his blankets on the ground he resolved that hereafter he would travel only at night, laying up in the daytime in the shade of the canyons.  He was exhausted with his terrible day’s march.  Never in his life had sleep seemed so sweet to him.

But suddenly he was broad awake, his jaded senses all alert.

“What was that?” he muttered.  “I thought I heard something—­saw something.”

He rose to his feet, reaching for the Winchester.  Desolation lay still around him.  There was not a sound but his own breathing; on the face of the desert not a grain of sand was in motion.  McTeague looked furtively and quickly from side to side, his teeth set, his eyes rolling.  Once more the rowel was in his flanks, once more an unseen hand reined him toward the east.  After all the miles of that dreadful day’s flight he was no better off than when he started.  If anything, he was worse, for never had that mysterious instinct in him been more insistent than now; never had the impulse toward precipitate flight been stronger; never had the spur bit deeper.  Every nerve of his body cried aloud for rest; yet every instinct seemed aroused and alive, goading him to hurry on, to hurry on.