In his work, he tries to convince his fellow Germans not to immigrate to the American colonies, as the forfeiture of freedom, cost of money, lack of health, and loss of life are too exorbitant to risk and sacrifice.
His meticulous account of his sea voyage to the British Atlantic colonies and subsequent experiences in Pennsylvania has become academically notable, due to the scarcity in primary source material concerning several of the issues he details.
Over the next two years, Mittelberger finished writing Journey to Pennsylvania, which was subsequently published in Stuttgart, with the permission of Duke Charles Eugene of Württemberg.
Observing from the perspective of a ship passenger aboard the Dutch vessel Osgood, Mittelberger documented the harrowing experiences of the 400 impoverished European immigrants making the transatlantic voyage from Rotterdam to Philadelphia.
Many do not even believe that there is a true God and a devil, a heaven and a hell, salvation and damnation, resurrection of the dead, a judgment and eternal life; they believe that all one can see is natural.
[9] As Mittelberger wrote of the American colonists: "To speak the truth, one seldom hears or sees a quarrel among them [which is] the result of the liberty which they enjoy and which makes them all equal.
Mittelberger describes the health conditions at sea as harrowing: But during the voyage there is on board these ships terrible misery, stench, fumes, horror, vomiting, many kinds of sea-sickness, fever, dysentery, headache, heat, constipation, boils, scurvy, cancer, mouth-rot, and the like, all of which come from old and sharply salted food and meat, also from very bad and foul water, so that many die miserably.
[11]Mittelberger continues: That most of the people get sick is not surprising, because, in addition to all other trials and hardships, warm food is served only three times a week, the rations being very poor and very little.
[12]As economic historian Farley Grubb states, there are scarce remaining sources in the world documenting 18th century transatlantic passenger fare.
[6] Similar to the religious tolerance of the era, colonial Philadelphia in the 1750s was relatively hospitable to various forms of sexual behavior and familial structure.
[6] As Lyons summarizes: According to Gottlieb Mittelberger...the town was a place of lax moral discipline, courtship went unregulated, women exercised too much power within marriage, and nonmarital sexuality rampant.