Pynchon characterizes Mason and Dixon by their actions and reactions to people and problems that they encounter on three continents. Never compatible, they bicker constantly. Mason considers his observations with the telescope as most important, but Dixon reminds him that without the transit and chain, they could not survey the line. They have contrasting personalities. Mason is a moody loner, while Dixon is gregarious and hyperactive. Mason wears a powdered wig, and Dixon wears a red jacket with silver buttons and a three-cornered hat. Mason speaks in British vernacular.

Dixon has distinctive Quaker speech patterns, using pronouns thee, tha, and huz. Mason is a Deist with spiritual conflicts, and Dixon is an expelled Quaker.

During their early association, Dixon encourages friendship, which Mason rejects. Dixon is an alcoholic who cannot endure solitude. In coffeehouses, taverns, and chicken fights, he mingles with gamblers, fortunetellers, sailors, slaves, and prostitutes. Mason...