Final answer:
Both work songs and field hollers sometimes referred to a 'captain' as the person who is in charge or leading the group.
Step-by-step explanation:
Both work songs and field hollers sometimes referred to a "captain" as the person who is in charge or leading the group. In the context of work songs, the captain could refer to a supervisor or overseer who directs the workers. In the context of field hollers, the captain could refer to a leader who sets the rhythm and guides the singer.
For example, in the lines 'The boatman singing what belongs to him in his boat, the deckhand singing on the steamboat deck,' the 'captain' would be the person in charge of the boat or steamboat, overseeing the workers.
Similarly, in the lines 'The machinist rolls up his sleeves, the policeman travels his beat, the gate-keeper marks who pass,' the 'captain' would be the supervisor or leader of the respective roles.