Long ago the younger men had ceased to laugh and joke. During the day they kept gazing steadily into the gulf of space that surrounded them, carefully scrutinizing the timber and the virgin brush which might form a covert; and at night they were sullen, expectant; every man wearing his gun when he rolled himself in his blanket. It was not fear that had seized them. They were rugged, hardy, courageous men who had looked death in the face many times, defying it, mocking it; and no visible danger could have disturbed them. But this danger was not visible; it was stealthy, secret, lurking near them, always threatening, always expected. It might stalk behind them; it might be flanking them as they rode; or it might creep upon them in the night. Blackburn had fallen into a vicious mood. His eyes glowed with the terrible, futile rage that surged in his veins, it was a reflection of a wrath that grew more and more intolerant as the days passed and the danger that portended did not materialize. "Boss," he said to Lawler on the tenth day following that on which Garvin had reported the presence of the riders behind them; "the boys is gettin' jumpy. They're givin' one another short answers, an' they're growlin' about things they never noticed before. "I'm gettin' fed up on this thing, too. It's a cinch them riders is following us. I seen 'em dustin' north of us this mornin'. I ain't said anything to the boys, but it's likely they've seen 'em, too--for they've got their eyes peeled. It's gettin' under my skin, an' if they don't come out into the open pretty soon and give us an idee of what game they're playin', me an' some of the boys is goin' to drag 'em out!" Yet Blackburn did not carry out his threat. He knew pursuit of the riders would be futile, for there were no further signs of them for several days, and Blackburn knew the riders would have no trouble in eluding them in the vast wilderness through which the herd had been passing for a week. They went on, continuing to watch, though there were no further signs of the men. They had been on the trail twenty days when at dusk one day they moved slowly down a wide, gradual slope toward a desert. At the foot of the slope was a water hole filled with a dark, brackish fluid, with a green scum fringing its edges. The slope merged gently into the floor of the desert, like an ocean beach stretching out into the water, and for a distance out into the floor of the desert there was bunch grass, mesquite, and greasewood, where the cattle might find grazing for the night. Beyond the stretch of grass spread the dead, gray dust, of the desert, desolate in the filmy, mystic haze that was slowly descending. The cattle came down eagerly, for they had grazed little during the day in the mountainous region through which they had passed. They were showing the effects of the drive. They had been sleek and fat when they started from the Circle L; they were growing lean, wild, and they were always ravenously hungry.