James narrates his account of colonial life with awe, and de Crèvecoeur instills a mood of wonder and even joy at the beginning of the novel as James remarks upon the various miracles of the colonies. This is especially evident in his passage on the bountiful natural wealth of Nantucket and the admirable industriousness of the whalers there.
Over the course of the novel, the mood gradually begins to darken as James delves into the underside of colonial life—including the reality that enslaved labor powers so much of the country's agriculture and the reality of how horrifically these enslaved people are treated. The culmination of this more brutal mood occurs at the end of Letter 9, when James comes upon a cage in the woods where an enslaved man has been left to die. As James declares of the scene:
Humanity herself would have recoiled back with horror; she would have balanced whether to lessen such reliefless distress or mercifully with one blow to end this dreadful scene of agonizing torture!
The mood never recovers after this moment—de Crèvecoeur has laid bare the true nature of American agricultural society. And as the book continues, things only worsen. The final letter is a discussion of the harsh American frontier in the shadow of the Revolutionary War, and as James fails to choose sides in the coming conflict, he must abandon his beloved farm and flee into the wilderness with his family.
