how does Jurgis gain employment as a digger of underground tunnels?

Jurgis gets ahold of a newspaper.

"It was a call for a hundred laborers, and though he thought it was a "fake," he went because the place was near by. He found a line of men a block long, but as a wagon chanced to come out of an alley and break the line, he saw his chance and sprang to seize a place. Men threatened him and tried to throw him out, but he cursed and made a disturbance to attract a policeman, upon which they subsided, knowing that if the latter interfered it would be to "fire" them all.

An hour or two later he entered a room and confronted a big Irishman behind a desk. Jurgis tells the truth to his questions but says he is strong and can work hard." The man gives him a job.