How the States Got Their Shapes Too_ The People Behind the Borderlines - Mark Stein [17]
Pennsylvania: 1681 charter borders
Not wanting any further disputes, Maryland and Pennsylvania agreed to seek the finest surveyors available. Pennsylvanian Benjamin Franklin—so revered as a scientist that he’d been inducted into England’s foremost academy, the Royal Society of London for the Improvement of Natural Knowledge—may have recommended Mason and Dixon. Their recent work had been sponsored by the Royal Society, and Franklin certainly knew of it, as would anyone perusing the news in 1762. London Magazine, for example, reported that “Messrs. Mason and Dixon, sent out by the Royal Society to observe the late transit of Venus over the sun, are returned from the Cape of Good Hope and have brought with them a most … excellent and satisfactory observation, for which they have received the thanks of that learned body.” The transit of Venus is a rare event in which the planet passes between the earth and the sun. It can be used to calculate the size of the solar system. How this is done was explained in the Royal Society’s report, published immediately after Mason and Dixon’s return, presenting their data and formulas computing parallaxes of latitude and longitude.
Asking Mason and Dixon to survey a boundary in America was thus akin to asking Mozart to play at a prom. Charles Mason was born in 1728, the son of a miller and baker. He demonstrated such brilliance at a young age that a mathematician in his home town of Gloucestershire helped finance his education. He joined the staff at the Greenwich Observatory, cobbling together an income from his nominal salary, a grant from a cartographic organization, and any fees he could earn for performing scientific tasks. With this he had to support a wife, who died young, and their two sons.
Jeremiah Dixon, five years younger than Mason, never married. The son of a coal mine owner, he was born in Bishop Auckland, County Durham, over 200 miles north of London. His family could well afford his schooling and introduced him to many eminent scientists with whom he established lasting relationships. Dixon was not, however, the stereotypical science nerd. He opted not to pursue an advanced education. He once told a job interviewer that his “seat of learning” for astronomy was “a pit cabin on Cockfield Fell”—the site of his father’s coal mine. Indeed, he may have learned astronomy in order to map mine shafts.2 A brief but revealing entry regarding young Dixon, whose family was Quaker, appears in the records of his local meeting: “Jery Dixon, son of George and Mary Dixon of Cockfield, disowned for drinking to excess.”3 At that time Dixon had already established himself as a surveyor who could, despite any love of liquor, walk off a line (or an arc or squiggle) on the ground exactly where it should be. His surveying skills were so highly regarded that the twenty-seven-year-old was chosen in 1760 to accompany the renowned scientist Charles Mason to the Cape of Good Hope to obtain data on the transit of Venus.
To survey the Pennsylvania-Maryland-Delaware boundary, Mason and Dixon began by establishing that Philadelphia’s southern boundary was the street wall at 30 South Street. From here they went thirty-one miles due west, where arrangements had been made at a farm for an observatory that would be their headquarters for the next four years.
But how did they know they had traveled due west? Apparently, following a compass isn’t sufficiently precise, as Mason and Dixon’s field notes reveal. “Computed the right ascension of the mid-heaven,” they noted, “when the *s [selected stars] passed the azimuth that would intersect the parallel of the post marked West, at 10’ to the westward of the said parallel.”4 Observing stars and crunching