250th Anniversary: Astronomy Helps Create Mason-Dixon Line

                                     
This photograph shows Pete Zapadka, a member of the Amateur Astronomers Association of Pittsburgh (AAAP), leaning on the Cornerstone Monument at the precise geographic location of the southwest corner of the Commonwealth of Pennsylvania--the official end of the Mason-Dixon Line. Although due to Native American territory disputes, astronomers Charles Mason and Jeremiah Dixon never saw this site; their portion of the Mason-Dixon Line Survey ended prematurely 23 miles short of this site, 250 years ago today (October 18). Philadelphia clock-maker and astronomer David Rittenhouse placed this monument and completed the Mason-Dixon Line Survey in 1784.
(Image Source: Amateur Astronomer Pete Zapadka)                            

By Glenn A. Walsh

Reporting for SpaceWatchtower

On this date 250 years ago (1767 October 18), astronomers Charles Mason and Jeremiah Dixon completed surveying most of the southern boundary of Pennsylvania [separating from the colonies of Maryland and Virginia (now the state of West Virginia)], what became the most famous boundary in U.S. history: the Mason-Dixon Line. Although contracted to survey to, what is now, the southwest corner of the Commonwealth of Pennsylvania, local Native Americans prevented the survey of the last 23 miles of the boundary line. Philadelphia clock-maker and astronomer David Rittenhouse headed a survey team which finished surveying those last 23 miles in 1784.

The whole idea behind the Mason-Dixon Line began with a colonial land dispute between two influential British families. In 1632, English King Charles I gave a grant of land, in the American Colonies, to Cecilius Calvert. The grant for what would become the colony of Maryland provided land north of Virginia and south of the 40^th parallel. Today, the City of Pittsburgh is located at the 40^th parallel, so this land grant included much of what is now southern Pennsylvania.

In 1681, King Charles II provided a second land grant to William Penn for what would become the Province of Pennsylvania. Although it did mention that the southern boundary of this land grant would be the 40^th parallel, much of the rest of the delineation of the land grant was convoluted and confusing. Hence, the Penn Family interpreted the grant to include land north of the 39th parallel.

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The Penn and Calvert families both claimed the land between the 39^th and 40^th parallels. And, since the thriving City of Philadelphia was within these two latitudes, this made the dispute even more contentious. However, such land disputes were common in the 17^th and 18^th centuries, as there had been little actual surveying in America and maps and land grants were often quite vague.

The Penn and Calvert families tried to convince the settlers of the disputed region that they lived in Pennsylvania or Maryland, respectively—and, they should pay taxes to the appropriate colony. Most colonists did not care which colony they lived in; but, they did not want to pay taxes to both colonies!

After several decades, the dispute actually led to war between Pennsylvania and Maryland! What became known as Cresap's War (named for Thomas Cresap, a Maryland partisan who had moved into, what is now York County, Pennsylvania, part of the disputed territory) was a series of skirmishes between the two colonies. Also known as the Conojocular War, militias from both Maryland and Pennsylvania fought for about a year or so, until King George II enacted a cease-fire in 1738.

In 1750, King George II created a formal truce between the two colonies. This truce granted most of the disputed territory to Pennsylvania. However, no one knew where the actual boundary line between the two colonies was located. So, in 1763 the Penn and Calvert families agreed to pay for a boundary survey. Well known English astronomers and surveyors Charles Mason and Jeremiah Dixon were hired to conduct this survey.

Charles Mason had been employed by the Royal Society in Greenwich, England to observe the stars and the Moon, and create lunar tables that could be used to determine longitude. Jeremiah Dixon was a surveyor, trained by a renowned maker of high-precision astronomical instruments, John Bird.

Mason and Dixon traveled through the wilderness of early Pennsylvania, Maryland, Delaware, and Virginia, using the stars to create the boundary line, now known as the Mason-Dixon Line. The boundary began 15 miles south of the southern-most tip of the City of Philadelphia.

The east-west, 233-mile line formed the southern boundary of Pennsylvania with Maryland, and for the area west of the beginning of the Potomac River, Virginia. Of course, during the American Civil War this section of Virginia seceded from the Commonwealth of Virginia and became the state of West Virginia.

They also surveyed the 83-mile western boundary of Delaware [then considered the 3 “Lower Counties on the Delaware” (New Castle, Kent, and Sussex) of the Province of Pennsylvania], separating, what would become, the second smallest state of the Union from Maryland.

At one-mile intervals, Mason and Dixon laid mile-marker stones all along the surveyed route. On the north side of the marker was chiseled the letter P for Pennsylvania; on the south side of the marker is the letter M for Maryland. As a five-mile marker, the stone included the Penn Family Coat of Arms on the north side of the stone and the Calvert Family Coat of Arms on the south side of the stone.

Each stone was a huge block of limestone, 3.5 to 5 feet long, weighing 300 to 600 pounds. These stones had come from a quarry in southern England. Mason and Dixon carried these stones with them, during the survey, using a horse and wagon.

Many of these stones survive. However, some are missing. For instance, one stone was hit by a snow-plow in January of 1996, and it was pushed down into a farmer's field. After more than 200 years, this particular stone now sits in a farmer's barn.

As the surveyors entered the Allegheny Mountains, they did not always lay stones at one-mile intervals. Instead, they created groupings of rocks or cairns as mile-markers.

Even in the 18^th century, surveying was not a new science. However, it was quite an achievement to survey a new boundary line in rugged terrain, often harsh weather, and with the constant risk of attack from Native Americans.

It usually took a couple of weeks, at least, for each set of astronomical observations for a particular mile-marker. They would spend clear-sky nights (of course, they could not work during cloudy nights) taking observations of stars, sometimes in very cold weather. They would have to lie on their backs and look through a 6-foot long telescope, measuring angles between stars and a north-south meridian line.

However, they did use state-of-the-art equipment. Jeremiah Dixon's mentor, John Bird, developed the Zenith Sector they used, which was the most advanced instrument of its day for determining latitude. According to John Bird, it was accurate to within 100 feet.

Scientists and geographers remember the work of Charles Mason and Jeremiah Dixon for two particular contributions to scientific literature:

1. They measured the first degree of latitude in the Americas;
2. They made the first scientific gravity measurements in the Americas.

The Pennsylvania land grant had extended 5 degrees of longitude west of the Delaware River, to the location of the southwest corner of Pennsylvania. Mason and Dixon had been commissioned to survey to the southwest corner of Pennsylvania. However, they never made it that far.

The Native American guides of Mason and Dixon refused to guide them into the territory of their enemy, the Shawnee and Delaware tribes. So, on Sunday, 1767 October 18, Mason and Dixon made their final observations before turning-back to return to Philadelphia, 23 miles short of their goal.

The following entry from Mason and Dixon's Journal, written by Charles Mason, describes setting the final mile-marker of their survey:

“Note: The Sector stood on the top of a very lofty Ridge, but when the Offset was made of 3 Chains 38 Links it fell a little Eastward of the top of the Hills; we therefore extended the true Parallel 3 Chains 80 Links Westward which fell on the top of the said Ridge; there viz. at 233 Miles 17 Chains 48 Links from the Post marked West in Mr. Bryan's Field, we set up a Post marked Won the West Side and heaped around it Earth and Stone three yards and a half diameter at the Bottom and five feet High. The figure nearly conical.”

After setting the last mile-stone, Mason and Dixon remained at the site until Tuesday, 1767 October 20, when their journal reported:

“Began to open a Visto in the True Parallel Eastward.”

Philadelphia clock-maker and astronomer, David Rittenhouse (along with surveyor Andrew Ellicott) completed surveying these last 23 miles in 1784. In addition to his scientific pursuits, University of Pennsylvania Astronomy Professor David Rittenhouse served as Treasurer of Pennsylvania from 1779 to 1787, and on behalf of the Federal Government he founded the U.S. Mint in 1792.

Although Mason and Dixon never reached the southwest corner of Pennsylvania, this was their contracted goal. Hence, the entire boundary line to the southwest corner of Pennsylvania is considered the Mason-Dixon Line. Although the Mason-Dixon Line does not follow an exact line of latitude, it is geographically located at approximately 39 degrees and 43 minutes North Latitude.

Beyond the end of the Mason-Dixon Line, at the southwest corner of Pennsylvania, the line continues west to the Ohio River, forming the boundary line between Marshall and Wetzel Counties in West Virginia. However, this county boundary line was formed by the Virginia Assembly in the latter part of the 18^th century and is not an official part of the Mason-Dixon Line.

In 1786, Andrew Ellicott was commissioned to survey the western boundary line of Pennsylvania (which came to be known as Ellicott's Line), from the end of the Mason-Dixon Line, north, to Lake Erie. Part of this boundary was between Pennsylvania and Virginia; the area of Virginia between Pennsylvania and the Ohio River now contains four counties (Hancock, Brooke, Ohio, and Marshall) in what is now the Northern Panhandle of West Virginia.

North of the location where the Ohio River leaves Pennsylvania, this boundary line codified the boundary between Pennsylvania and the Federal Territory known as the “Ohio Country,” part of the Northwest Territory. This boundary line was important because Pittsburgh and a small part of Western Pennsylvania had originally been considered part of the Ohio Country (an area that had been roughly defined as west of the Allegheny Mountains, north of the Ohio River, and south of Lake Erie). The vast majority of the Ohio Country was admitted to the Union as the State of Ohio on 1803 March 1.

The Mason-Dixon Line has come to be known as the dividing line between the northern United States and the southern United States. This division began as early as 1790 March 1, when the Pennsylvania General Assembly passed legislation banning slavery in the Commonwealth. As Maryland still allowed slavery (as did Delaware and Virginia), by 1804 the Mason-Dixon Line came to be seen as the dividing line between the slave states (in the South) and free states (in the North).

During the first half of the 19^th century, the Mason-Dixon Line came to be known, by slaves fleeing their southern masters, as the line of freedom. The Underground Railroad consisted of abolitionists at secret way-stations who would help African-Americans from the South cross the Mason-Dixon Line on their way to freedom and a new life.

A spiritual song sung by these run-away slaves, “Follow the Drinking Gourd,” helped these mostly illiterate refugees find their way north. The song reminded them to search for the Big Dipper asterism in the night sky, which would help them find the North Star, Polaris.

The Mason-Dixon Line was mentioned during Congressional debates leading to the Missouri Compromise of 1820, which allowed Missouri to enter the Union as a slave state, while Maine entered the Union as a free-soil state. At that time, politicians considered the Mason-Dixon Line, and extending further west along the Ohio River, as the boundary line between slave and free-soil states. The Missouri Compromise legally forbade the admission of states, which had been part of the Louisiana Purchase territories, as slave states if they existed north of Latitude 36 degrees, 30 minutes North (the southern boundary of Missouri); however, the legislation also allowed one exception: Missouri.

When the American Civil War, or War Between the States, erupted in 1861, the Mason-Dixon Line was still considered a dividing line between North and South. But because Washington, DC, a southern city, had been chosen as the site of the new nation's capital (due to the Compromise of 1790, which allowed the Federal Government to pay-off Revolutionary War debts of the states, in return for locating the national capital in the South), the Federal Government refused to allow Maryland to join the Confederate States of America (CSA), even though Maryland (along with pro-Union border states Delaware, Kentucky, and Missouri) continued to allow slavery.

In the middle of the Civil War, 50 counties in western Virginia broke-away from Virginia (which included the state capital, Richmond, as the capital of the Confederacy) to form a new state, West Virginia, which was admitted to the Union on 1863 June 20. On that date, no longer did any portion of the Mason-Dixon Line touch the Commonwealth of Virginia; the section of the Mason-Dixon Line previously bordering Virginia now bordered West Virginia.

Derived from the title, Mason-Dixon Line, and the surname of Jeremiah Dixon, “Dixie” became a name generally identifying the southern United States in the early 19^th century. During the Civil War, it was generally used to refer to the Confederacy.

The song, “Dixie” or “I Wish I Was in Dixie,” probably reinforced the popular notion that Dixie meant the American South. The song became the unofficial anthem of the Confederacy during the Civil War, after being played during the inauguration of Confederate President Jefferson Davis in 1861. Upon hearing of the Confederate General Robert E. Lee's surrender at Appomattox County, Virginia in 1865, U.S. President Abraham Lincoln asked the military band to play “Dixie.”

There is still some dispute regarding who wrote the song, although it seems the song may have been authored by Daniel Emmett, a Northerner from Mount Vernon, Ohio in 1859. It quickly became popular through black-face minstrel shows.

Today, the song “Dixie” is still popular in the South. And, the term Dixie is still used to represent the South. In fact, a popular grocery store chain in the South, known as Winn-Dixie (headquartered in Jacksonville), operates 495 stores in five southern states (Alabama, Florida, Georgia, Louisiana, and Mississippi).

Interestingly, a handsome, 10-story office building in a northern city is called Dixie Terminal. Built in Downtown Cincinnati in 1921, this building is located only dozens of feet from the Ohio River. It was named Dixie Terminal because it was once a streetcar terminal (later commuter bus terminal) for streetcars coming from Dixie--that is, the suburbs of Northern Kentucky.

                                        

Internet Links to Additional Information ---

Photograph of Historical Marker near end of Survey conducted by Mason and Dixon:
Link >>> http://spacewatchtower.blogspot.com/2017/10/astronomical-calendar-2017-october.html

Mason-Dixon Line Survey web-site ExploretheLine, with photos of survey markers:
Link >>> http://www.exploretheline.com/index1.html 

Charles Mason: Link >>> https://en.wikipedia.org/wiki/Charles_Mason 

Jeremiah Dixon: Link >>> https://en.wikipedia.org/wiki/Jeremiah_Dixon 

David Rittenhouse: Link >>> https://en.wikipedia.org/wiki/David_Rittenhouse 
     University of Pennsylvania Astronomy Professor David Rittenhouse inspires the field of stars on 
     the American Flag: Link >>> http://spacewatchtower.blogspot.com/2017/06/240th-anniversary-of-american-flag-why.html

Andrew Ellicott: Link >>> https://en.wikipedia.org/wiki/Andrew_Ellicott

Special Thanks: Amateur Astronomer Pete Zapadka.

Source: Glenn A. Walsh Reporting for SpaceWatchtower, a project of Friends of the Zeiss.
             2017 October 18.

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