English astronomer and surveyor (1728?1786)
Charles Mason
(25 April 1728
[1]
– 25 October 1786) was an English-American
astronomer
who made significant contributions to 18th-century science and American history, particularly through his
survey
with
Jeremiah Dixon
of the
Mason?Dixon line
, which came to mark the border between Maryland and Pennsylvania (1764?1768). The border between Delaware and Maryland is also defined by a part of the Mason?Dixon line.
Early career
[
edit
]
Mason's early career was spent at the
Royal Greenwich Observatory
near
London
. He served as assistant astronomer from 1756 to 1760 under the Reverend
James Bradley
, the third
Astronomer Royal
.
While employed at the Greenwich Observatory, Mason became familiar with Professor
Tobias Mayer
's
Tables of the Moon
. The
Lunar Tables
were designed to solve the
problem of determining longitude at sea
, a challenge that frustrated scientists and navigators for decades. Mason worked throughout his life to perfect the
Lunar Tables
as a method of improving navigation at sea. In 1787, Mason's work was recognized, and he was awarded £750 (not the full prize of £10,000 to £20,000) by the
Board of Longitude
for his work on perfecting the
Tables
.
[2]
1761 transit of Venus
[
edit
]
In 1761, Mason was assigned to travel to the island of
Sumatra
to observe the
transit of Venus
as part of an international effort to record data that would enable scientists to determine the distance from the Earth to the Sun. Mason was joined by
Jeremiah Dixon
, a surveyor and amateur astronomer from
Cockfield
in the County of Durham. Owing to an attack by a French
man-of-war
, they did not reach their destination in time for the transit and were forced to record their observations from the
Cape of Good Hope
. On the way back from the Cape they visited
St Helena
where they made a series of observations with the astronomer
Nevil Maskelyne
.
The Mason?Dixon line survey
[
edit
]
From November 1763 to 1768, Mason and Jeremiah Dixon established the boundary line between the American provinces of
Pennsylvania
and
Maryland
.
[3]
Colonial surveyors had been unable accurately to establish the boundary due to their poor training and inadequate scientific instruments. Mason and Dixon, accompanied by a large party of assistants, established three important boundaries: (1) the south boundary line of Pennsylvania separating it from Maryland and
Virginia
; (2) the west boundary of the three lower counties of Pennsylvania (now
Delaware
) separating it from Maryland; and (3) the south boundary of the three lower counties. The pair also conducted a number of experiments for the
Royal Society
such as measuring a degree of latitude. Mason's journal provides the most complete record of the survey and its progress. The journal includes his astronomical observations and personal notes about the American frontier environment and his experiences in colonial America.
Mason and Dixon failed to measure the entire length of the south boundary of Pennsylvania as determined by its charter. In the summer of 1767, the surveying party crossed the
Monongahela River
and the
Great Catawba War Path
, violating a treaty limiting the westward expansion of English settlements. Not wishing to risk inciting native hostilities, Mason and Dixon were forced to return east after making their final observations at the crest of Brown's Hill.
Career after the Mason?Dixon line survey
[
edit
]
After completing the boundary survey in the United States, Mason returned to Greenwich where he continued work on Mayer's
Lunar Tables
. He also contributed to the
Nautical Almanac
, working under
Nevil Maskelyne
, the fifth Astronomer Royal.
On 27 September 1786, Mason wrote to
Benjamin Franklin
, whom he knew from his election to the
American Philosophical Society
in 1767 where Franklin was a founding member, informing him that he had returned to Philadelphia with his wife, seven sons, and one daughter.
[4]
Mason was very ill and confined to his bed. Mason also shared with Franklin the design for an astronomical project. Mason provided no explanation for his return to the United States, and nothing more is known of Mason's proposed project.
[5]
Mason died on 25 October 1786, in Philadelphia. He was buried there in
Christ Church Burial Ground
.
Posthumous recognition
[
edit
]
The crater
Mason
on the
Moon
is named after him.
Mason is one of the title characters of
Thomas Pynchon
's 1997 novel
Mason & Dixon
. The song "Sailing to Philadelphia", inspired by Pynchon's book, appears on
Mark Knopfler
's
album of the same name
; on the original version, Knopfler sings the role of Dixon and
James Taylor
that of Mason.
[6]
Surveying organizations dedicated a memorial at his previously unmarked grave on 31 August 2013, using a Mason?Dixon line stone that was found displaced from its position.
[7]
Notes
[
edit
]
- ^
a
b
mdlpp: A NOTE ON CHARLES MASON'S ANCESTRY AND HIS FAMILY, H. W. ROBINSON, Lately Librarian of the Royal Society of London
Archived
4 March 2016 at the
Wayback Machine
. Retrieved 6 July 2015
- ^
Cope, Thomas D.
and H. W. Robinson. "Charles Mason, Jeremiah Dixon and the Royal Society."
Notes and Records of the Royal Society of London
. vol 9, no 7, 1751. p 75.
- ^
"A Plan of the West Line or Parallel of Latitude"
.
World Digital Library
. 1768
. Retrieved
1 July
2013
.
- ^
Bell, Whitfield J., and Charles Greifenstein, Jr. Patriot-Improvers: Biographical Sketches of Members of the American Philosophical Society. 3 vols. Philadelphia: American Philosophical Society, 1997, 1:366-373.
- ^
Cope, Thomas D.
"Some Contacts of Benjamin Franklin with Mason and Dixon in Their Work".
Proceedings of the American Philosophical Society
. 95 (1751) p 238
- ^
"Off the Straits and narrow"
.
The Independent
. 22 September 2000
. Retrieved
27 May
2009
.
- ^
"Rendezvous 2013"
. Surveyors Historical Society. Archived from
the original
on 19 July 2013.
External links
[
edit
]
|
---|
International
| |
---|
National
| |
---|
Other
| |
---|