She could track either of the partners for miles, nose to earth; nearly always forewarned in some occult manner to avoid obstacles in her path. She was even, in a small way, of help to Treve in rounding up sheep. And ever that strange instinct--a sort of sixth sense--developed more and more, as her brain and experience developed. Around the house she was the sweetest and most loving of pets; though her real adoration and slavish worship were lavished on Treve alone. She was his shadow. And to her he accorded a tender friendliness which he had refrained haughtily from bestowing on the splay-footed little black range collies. It was nearly six months after the coming of Nellie that the blizzard struck the Dos Hermanos region. In that southerly and semi-arid stretch, snow was a rarity. Heavy snows were practically unknown in the lowlands. Storms, which whitened the Dos Hermanos peaks and slopes, fell usually as rain in the valley. But now, in mid-February, came a genuine blizzard. It caught the ranch totally by surprise. The various bunches of sheep were grazing wide; as usual at that rain-flecked time of year. Out of a softly blue sky came a softer grayish haze. Two hours later the blizzard was roaring in full spectacular fury. Every man and every dog was pressed into service. Floundering knee-deep through drifts, the partners and their herdsmen and Sing Lee, the new Chinese cook, sought puffingly to drive the scattered and snow-whipped sheep to places of shelter. The dogs, half-submerged in the floury snow, staggered and fought their way in the teeth of the blast and the stabbing cold. Their pads were tight-packed with painful snow-lumps. There was no time to stop and gnaw these torments out. The dogs drove on, limping, unresting. It was a madly busy three or four hours. Men and dogs alike were blinded by the whirling tons of snow. There was no such thing as following a scent, with any accuracy, through that smother. Nor could a voice be heard, fifty feet away, in the screech of the gale. Spent, dizzy, numb, the partners came back at last to their snow-piled home. The storm had ceased as suddenly as it had begun. Already a watery sunshine was beginning to glisten on the ocean of snow that spread everywhere. “All safe except the bunch on Six Range,” reported Royce breathlessly as he and Fenno met, near the gate. “It was touch-and-go, with the whole lot. But those got tangled up somehow in the blizzard and bolted. Treve and I worked for two hours to find them. But it was no good. They’ve stampeded over the rock wall of the coulée or else over the cliff into the river. Either way, they’re goners. In a storm like that they--” He stopped short. The dazzling white snow around the house was darkened by a shifting and huddling mass of dirty gray. The partners squinted their snow-blurred eyes to see what the phenomenon might mean.