Final answer:
The songs in the poem are a metaphor for unity in American society, as expressed through the work of various individuals.
Step-by-step explanation:
The songs in the poem are a metaphor for unity in American society, as expressed through the work of various individuals. For example, in the line 'The mechanic singing as he makes ready for work,' the mechanic represents one profession that contributes to the overall unity. This metaphor suggests that different individuals, each with their own unique roles and skills, contribute to the harmony and unity of American society.
The primary topic of this question is the metaphorical meaning of the songs in the poem.