Drawing the Line
Anna Edmonds
The Transit of Venus that Bill and I were privileged to see this past June has reminded me of a British team of two astronomers/surveyors. These men were sent to the island of Sumatra to observe the Transit of Venus in 1761. Our experience in the 2004 transit was blissfully uneventful (except for getting interviewed on Turkish television). Theirs was not. On their second day en route to Sumatra, their ship was attacked by French pirates. When they suggested to their sponsor that their expedition might be more expensive than successful, they were warned that their reputations were at stake. They continued, only to learn that Sumatra had become French territory. Since Britain and France were at war, their arrival would put more than their reputations at risk. (They managed to observe the transit at the Cape of Good Hope on June 6.)
Granite boundary marker bearing the Penn and Baltimore Arms
However, now that they were experienced in the complications of field work and had the reputation as good working partners, they were sent off to survey and settle a border dispute in the American wilderness. They labored there from 1763 to 1767—only a decade before the Americans decided that they didn’t want the British around any more.
Back home they were most acclaimed for determining the measure of a degree of meridian. But for the Americans, it was the determination of “the fortieth degree of north latitude from the equatorial” and the resulting settlement of the dispute. (Actually, the border in question is at 39° 43’.) The two properties in question belonged then to Cecelius Calvert, Lord Baltimore and William Penn, and the settlement established the boundary between Maryland and Pennsylvania. In the Missouri Compromise of 1820 that border separated the slave-owning South from the slave-free North and became known as the Mason-Dixon Line, named for the two surveyors, Charles Mason and Jeremiah Dixon.
You can’t ever tell what you’re going to get into with astronomy.