That a free laborer is a mobile laborer, especially in a society like the United States that had this thing called The West, the limitless apparently to them anyway--boundless West.

自由劳动者是流动的,尤其处在美国这样的社会,有他们所说的广袤的西部,特别对他们来说,无边际的西部

耶鲁公开课 - 美国内战与重建课程节选