_____The narrative begins in a large house in or near Philadelphia at Christmastime (or a "snowy Advent") in 1786. It's not clear yet who the narrator is at this point in the novel, but he (or she) will relinquish it to another voice after the scene is set.
It has become an afternoon habit for the Twins and their Sister, and what Friends old and young may find their way here, to gather for another Tale from their far-travel'd Uncle, the Revd Wicks Cherrycoke, who arriv'd here back in October for the funeral of a Friend of years ago, -- too late for the Burial, as it prov'd, -- and has linger'd as a Guest in the Home of his sister Elizabeth, the Wife, for many years, of Mr. J. Wade LeSpark, a respected Merchant in Town Affairs, whilst in his home yet Sultan enough to convey to the Revd, tho' without ever so stipulating, that, for as long as he can keep the children amus'd, he may remain, -- too much evidence of Juvenile Rampage at the wrong moment, however, and Boppo! 'twill be Out the Door with him, where waits the Winter's Block and Blade.So Cherrycoke yields to the entreaties of the twins, Pitt and Pliny, so named "that each might be term'd 'the Elder' or 'the Younger,' as might day-to-day please one, or annoy his Brother." He begins a story about the surveying expedition of Charles Mason and Jeremiah Dixon, on which he says he took part.
Mason is dead, and Cherrycoke, who arrived too late for the funeral, every day makes a visit to his grave. Cherrycoke himself is a rather dubious parson, and Pitt observes that his mother calls him "the Family outcast," and Pliny that "They pay you money to keep away." Cherrycoke claims that back in England he was once almost hanged for posting bills listing the names of perpetrators "of certain Crimes I had observ'd, committed by the Stronger against the Weaker." Judged to be insane, he was sent to sea on the Seahorse.
We cut to a letter from Dixon to Mason, who is Assistant to the Astronomer Royal, in which Dixon announces himself as Mason's "Second upon the propos'd Expedition to Sumatra, to observe the Transit of Venus."
Cherrycoke returns to the story, admitting that he wasn't there when Mason met Dixon, but that he had heard the story from them. Dixon was from Durham, in the northeast of England, and something of a bumpkin in the city. He's surprised when Mason mocks his accent, but manages to get even with a joke, which embarrasses the rather too serious Mason. Dixon is taller and "the first to catch the average Eye, often causing future strangers to remember them as Dixon and Mason." He was also raised a Quaker.
Mason, having expected some shambling wild Country Fool, remains amiably puzzl'd before the tidied Dixon here presented, -- who, for his own part, having ... expected but another over-dress'd London climber, is amus'd at Mason's nearly invisible Turn-out, all in Snuffs and Buffs and Grays.They are in Portsmouth, awaiting the embarkation, and decide it's their "last chance for civiliz'd Drink." In a tavern they encounter "a somewhat dishevel'd Norfolk Terrier, with a raffish Gleam in its eye." The dog then sings a song, announcing himself as "the Learnéd English Dog," willing to answer any question. Dixon observes Mason's fascination with the dog, but when Mason starts to ask a rambling question, the dog "sighs deeply" and says, "See me later, out in back." Outside, they meet Fender-Belly Bodine, who is captain of the foretop of the Seahorse, their ship, who notes their interest in the dog.
Mason's question of the dog is "Have you a soul, -- that is, are you a human Spirit, re-incarnate as a Dog?" The dog replies that he is not there to provide "religious Comfort": "I may be praeternatural, but I am not supernatural." He tells them that dogs used to be kept by humans for food, so dogs, noting that cannibalism was taboo, "learn'd to act as human as possible." He is "but an extreme Expression of this Process." Bodine expresses interest in buying the dog, but his "Exhibitor," Mr. and Mrs. Jellow, say that he's not for sale.
Dixon, "who for some while has been growing increasingly desperate for a drink," notices that they are near the Pearl of Sumatra, and Bodine invites the dog, who says, "Pray you, call me Fang," to join them. In the saloon, a vast hive of multiple vices including cock-fighting and other forms of gambling, Fang points out Dark Hepsie, the Pythoness of the Point," and tells Mason that she's the one he should consult for prophecy. Dixon quickly spots that Hepsie is actually an attractive young woman in disguise. When Hepsie notes that they plan to sail on Friday, a day of ill omen, being the day of the crucifixion, Mason suggests that they should sail on another day.
"Mason, pray You, -- 'tis the Age of Reason," Dixon reminds him, "we're Men of Science. To huz must all days run alike, the same number of identical Seconds, each proceeding in but one Direction, irreclaimable....? If we would have Omens, why, let us recall that the Astronomer's Symbol for Friday is also that of the planet Venus herself, -- a good enough Omen, surely ...?"So they take their leave of Hepsie and Fang, though Mason wants to ask them more, and in the morning he can't find anyone who knows anything about them. "He will continue search, even unto scanning the short as the Seahorse gets under way at last, on Friday, 9 January 1761."