Low over leagues of frost-enchanted plain,
Saw Glass upon his pilgrimage again,
Northbound as hunter for the keelboat’s crew.
And many times the wide autumnal blue
Burned out and darkened to a deep of stars;
And still they toiled among the snags and bars—
Those lean up-stream men, straining at the rope,
Lashed by the doubt and strengthened by the hope
Of backward winter—engines wrought of bone
And muscle, panting for the Yellowstone,