Question: When was the American explorer which Andrew Ellicott  served as a teacher in survey methods for born 

full_context: Document 1: Meriwether Lewis: Meriwether Lewis (August 18, 1774 – October 11, 1809) was an American explorer, soldier, politician, and public administrator, best known for his role as the leader of the Lewis and Clark Expedition, also known as the Corps of Discovery, with William Clark.
Document 2: Thomas Walker (explorer): Thomas Walker (January 25, 1715 – November 9, 1794) was a distinguished physician and explorer from Virginia; in the mid-18th century, he was part of an expedition to the region beyond the Allegheny Mountains and the unsettled area of British North America. Walker and fellow Virginian, Indian agent, explorer for Patrick Henry, legislator of three states, surveyor of KY/VA & TN/NC borders, and later Revolutionary war general, Joseph Martin, were some of the first colonialists to travel in this area. Martin's son, Revolutionary War officer Col. William Martin, describes the naming of the area and river in a letter to historian Lyman Draper,
Document 3: Benjamin Banneker: Benjamin Banneker (November 9, 1731October 9, 1806) was a free African American almanac author, surveyor, naturalist, and farmer. Born in Baltimore County, Maryland, to a free African American woman and a former slave, Banneker had little formal education and was largely self-taught. He is known for being part of a group led by Major Andrew Ellicott that surveyed the borders of the original District of Columbia, the federal capital district of the United States.
Document 4: Ellicott's Rock: In 1811, Andrew Ellicott made a survey for the state of Georgia to resolve the boundary dispute between Georgia and North Carolina, which in 1810 had resulted in a short armed conflict between the two called the Walton War. He engraved a large rock in the Chattooga River with "N-G", standing for North Carolina - Georgia. The location had been prescribed in part in 1787 by the Treaty of Beaufort, though the river was not named explicitly, but rather as a then-undiscovered tributary of the Savannah River between Georgia and South Carolina. The nominal latitude of 35°N was later specified by the U.S. Congress.
Document 5: George Rogers Clark: George Rogers Clark (November 19, 1752 – February 13, 1818) was a surveyor, soldier, and militia officer from Virginia who became the highest ranking American military officer on the northwestern frontier during the American Revolutionary War. He served as leader of the militia in Kentucky (then part of Virginia) throughout much of the war. Clark is best known for his celebrated captures of Kaskaskia (1778) and Vincennes (1779) during the Illinois Campaign, which greatly weakened British influence in the Northwest Territory. Because the British ceded the entire Northwest Territory to the United States in the 1783 Treaty of Paris, Clark has often been hailed as the "Conqueror of the Old Northwest".
Document 6: Mythology and legacy of Benjamin Banneker: A substantial mythology exaggerating Benjamin Banneker's accomplishments has developed during the two centuries that have elapsed since he lived. Several such urban legends describe Banneker's alleged activities in the Washington, D.C. area around the time that he assisted Andrew Ellicott in the federal district boundary survey. Others involve his clock, his almanacs and his journals. All lack support by historical evidence. Some are contradicted by such evidence.
Document 7: Andrew Ellicott: Andrew Ellicott (January 24, 1754 – August 28, 1820) was a U.S. surveyor who helped map many of the territories west of the Appalachians, surveyed the boundaries of the District of Columbia, continued and completed Pierre (Peter) Charles L'Enfant's work on the plan for Washington, D.C., and served as a teacher in survey methods for Meriwether Lewis.
Document 8: Henry Gannett: Henry Gannett (August 24, 1846 – November 5, 1914) was an American geographer who is described as the "Father of the Quadrangle" which is the basis for topographical maps in the United States.
Document 9: Aaron Carapella: Aaron Carapella is a self-taught cartographer who makes maps of the locations and names of Pre-Columbian Indigenous tribes of North America circa 1490. He is part Cherokee on his mother's side and his grandparents instilled a deep interest in Native American culture. At age 19, he began his map-making research and as of 2014, he has made maps of indigenous tribes with their original names for the continental United States, Canada, and Mexico.
Document 10: Lewis Cass: Lewis Cass (October 9, 1782June 17, 1866) was an American military officer, politician, and statesman. He represented Michigan in the United States Senate and served in the Cabinet of Andrew Jackson and James Buchanan. He was also the 1848 Democratic presidential nominee and a leading spokesman for the Doctrine of Popular Sovereignty, which held that the people in each territory should decide whether to permit slavery.
Document 11: Ellicott's Stone: Ellicott’s Stone, also known as the Ellicott Stone, is a boundary marker in northern Mobile County, Alabama. It was placed on April 10, 1799 by a joint U.S.-Spanish survey party headed by Andrew Ellicott. It was added to the National Register of Historic Places on 11 April 1973.
Document 12: Lewis &amp; Clark (TV series): Lewis & Clark is an American sitcom that aired on NBC for one season from October 29, 1981 to July 30, 1982. The series stars Gabe Kaplan (who also created the series) and Guich Koock.
Document 13: Lewis and Clark Pass (Montana): Lewis and Clark Pass, el. 6424 ft is a mountain pass on the continental divide in Montana. It lies at the head of the drainages of the west flowing Blackfoot River and the east flowing Dearborn River. The pass is in the Helena National Forest in Lewis and Clark County. The Continental Divide Trail traverses north and south through the pass. At the time of the Lewis and Clark Expedition the pass was a much-used pathway where the native people living in what today is Montana crossed over the continental divide. The pass was crossed by Meriwether Lewis on July 7, 1806, on the return leg of the Lewis and Clark Expedition with a party of nine men and his dog Seaman. The pass was named for the expedition's two leaders–Lewis and William Clark. Lewis and Clark Pass is the only roadless pass on the entire Lewis and Clark National Historic Trail. It has gone from being one of the most used continental divide passes prior to the pioneer era to one of the least visited passes today. It can be accessed by a 1.5 mi trail. Visitors will encounter the pass much as Lewis did in 1806. The furrows left by the countless dog and horse travois that crossed the pass are still visible (though fading) and this is one of the places along the expedition's route that visitors may still encounter a grizzly bear. On a clear day, like Meriwether Lewis in 1806 one can see Square Butte in Cascade County, Montana, 40 mi to the northeast.
Document 14: Lewisia: Lewisia is a plant genus, named for Meriwether Lewis who encountered the species in 1806. The native habitat of "Lewisia" species is north facing cliffs in the western part of North America. Local Native Americans ate the roots, which have also been used to treat sore throats.
Document 15: William Sublette: William Lewis Sublette also spelled Sublett (September 21 1798 - July 23 1845), was a pioneer, frontiersman, trapper, fur trader, explorer, and mountain man, who, with his four brothers, after 1823, became an agent of the Rocky Mountain Fur Company and later, one of its co-owners, exploiting the riches of the Oregon Country, which helped settle and improve the best routes, along the Oregon Trail.
ground_truth: August 18, 1774