On April 5th the last of the steel for Span Number One reached the front, and erection was begun. The men fell to with a vim and an enthusiasm impossible to describe. With incredible rapidity the heavy sections were laid in place; the riveters began their metallic song; the towering three bent traveler ran smoothly on its track, and under it grew a web work of metal, braced and reinforced to withstand, in addition to ordinary strains, the pressure of a hundred-mile-an-hour wind. To those who looked on, the structure appeared to build itself, like some dream edifice; it seemed a miracle that human hands could work that stubborn metal so swiftly and with so little effort. But every piece had been cut and fitted carefully, then checked and placed where it was accessible. Now that winter had broken, spring came with a rush. The snows began to shrink and the drifts to settle. The air grew balmier with every day; the drip from eaves was answered by the gurgling laughter of hidden waters. Here and there the boldest mountainsides began to show, and the tops of alder thickets thrust themselves into sight. Where wood or metal caught the sun-rays the snow retreated; pools of ice-water began to form at noon. The days were long, too, and no frozen winds charged out of the north. As the daylight lengthened, so did the working-hours of the toilers. On April 18th the span was completed. In thirteen days Mellen's crew had laid four hundred feet of the heaviest steel ever used in a bridge of this type. But there was no halt; the material for the second section had been assembled, meanwhile, and the traveler began to swing it into place. The din was unceasing; the clash of riveters, the creak and rattle of hoists, the shouts of men mingled in a persistent, ear-splitting clamor; and foot by foot the girders reached out toward the second monolith which rose from the river-bed. The well-adjusted human machine was running smoothly; every man knew his place and the duties that went with it; the hands of each worker were capable and skilled. But now the hillsides were growing bare, rills gashed the sloping snow-fields, the upper gullies began to rumble to avalanches--forerunners of the process that would strip the earth of snow and ice and free the river in all its fury. In six days three hundred feet more of steel had been bolted fast to the complete section, and Span Two was in place. But the surface of the Salmon was no longer white and pure; it was dirty and discolored now, for the debris which had collected during the past winter was exposing itself. The icy covering was partially inundated also; shallow ponds formed upon it and were rippled by the south breeze. Running waters on every side sang a menace to the workers.