Table of Contents:

    Goals

    Preparatory Assignment

    Nautical History

    Brief History of Sierra Leone

    Brief History of Latitude and Longitude

    Instruments on board a Ship

    Latitudes and Longitudes of Key Places

    Exploring Amistad Resources

    Student Exercises

    Make your own instruments!

    Discussion Questions

    Contacts

Suited for Grades: High School

Goals of this exercise:

Students will examine aspects of the Amistad incident using the disciplines of Geography, Mathematics, Technology, History, Sociology, and Science. Through the use of maps, charts, and navigational instruments, students will follow the voyages the Teçora, the Amistad, and the Gentleman made throughout the Atlantic Ocean, with the Africans on board.

Preparatory Assignment:

It is important for the students to understand the issues surrounding the Amistad Incident. For a preliminary look at the Amistad Revolt, the curriculum piece called "An Introduction to the Amistad Revolt," developed by the Connecticut Historical Society, may be useful.

Nautical History:

In April, 1839, approximately five hundred Africans were kidnapped, chained, and brought aboard the ship Teçora in Lomboko, Sierra Leone, bound for Havana, Cuba. During the 4200 nautical mile voyage, which lasted about 58 days, nearly one third of the Africans died. Those remaining on the Teçora were sold in the Cuban Slave Market, including forty-nine adult males, and four children of other descent, who were sold to Jose Ruiz and Pedro Montez, and were placed on board the Schooner Amistad. The Amistad sailed from Havana on the 28th of June, 1839, bound for Puerto Principe, Cuba, a distance of some 240 nautical miles. On July 2, 1839, the Africans revolted against their captives and sailed for the next two months, east by day and north by night, eventually reaching the waters off of the United States eastern coast. The schooner was taken near Montauk Point, Long Island, New York, only 1200 nautical miles north of where the voyage had started. The ship was escorted to New London, Connecticut by the U.S. Brig Washington.. Over the next few years, the United States deliberated over the status of the Africans. On March 9, 1841, the Supreme Court of the United States affirmed the lower court's decision to recognize the surviving Africans' freedom. A few months later, thirty five of the original fifty three Amistad Africans boarded the ship Gentleman in New York bound for their homes in Sierra Leone, a distance of 3796 nautical miles. For a more complete review of events, use the Exploring Amistad Timelines.

Brief History of Sierra Leone:

Sierra Leone was one of the first British West African colonies. Foreign settlement began there in about 1787, as former slaves from Europe established Freetown. The United Kingdom abolished slavery in its colonies in 1833, and Sierra Leone obtained independence on April 27, 1961. Sierra Leone, encompassing 71,740 square miles, is slightly smaller than South Carolina. It has a population of about 5 million people, 30% of whom are Mendi, like the Amistad Africans. Another 30% of the population belongs to the Temne tribe, while 39% belongs to eleven other tribes, and only 1% is of foreign ethnic descent. Life expectancy today is about 47.5 years. Sierra Leone lies between 7° & 10° N Latitude and 11° & 13° W Longitude. Here are some links about modern day Sierra Leone that may be useful:

    Sierra Leone Page

    A Link to Sierra Leone

    The Sierra Leone Notebook

    Sierra Leone Web

Brief History of Latitude and Longitude:

Hipparchus (circa. 180-125 BCE) is credited with developing the first regular global system of latitude and longitude around 150 BCE. Parallels and meridians are divided into 360° (degrees), with each degree divided into 60´ (minutes), and each minute divided into 60´´ (seconds).The sexigesimal system was a legacy of the Babylonians. Hipparchus also developed trigonometry, the stereographic projection and the astronomer's astrolabe.

Claudius Ptolemy (circa. 150 CE) first suggested that Alexandria be the prime meridian, with longitudes running up to 90° east and 90° west. Later the Fortunate (Canary) Islands and the Isles of the Blest from Greek Mythology were used as his prime meridian. When Ptolemy's work was rediscovered during the Renaissance, Ferro (Hiero) in the Canary Islands became the prime meridian with longitudes running 0° to 180° E.

Starting in 1767 with the publication of the British Nautical Almanac, nations slowly started using Greenwich, England, which housed a large observatory, for the prime meridian on charts and maps that they produced. In 1884, at the International Meridian Conference in Washington, D.C., U.S.A., 41 delegates from 25 nations met to adopt Greenwich as the uniform world meridian to replace the several existing ones. Here are some links about Latitude, Longitude, and the Prime Meridian that may be useful:

    Latitude and Longitude

    How far is it?

    Measuring the World

    Mobile Aeronautics Education Laboratory: Latitude/Longitude Plotting

    Origin of the Prime Meridian

Instruments of use on board a ship in the 1840's: Instruments used by navigators on ships included: charts, parallel rulers, dividers, pencil, lead line, telescope, magnetic compass, log & sandglass timer, octant, Nautical Almanac, mathematical tables, and chronometer. According to the Inventory and Appraisal of the Schooner Amistad, some instruments that belonged to the ship were: lead & line, for measuring depth of water and sampling the bottom; two brass compasses; three sand glasses (sand glass timers), probably half a minute long; and a log reel used for measuring the ship's speed. View the complete list of articles belonging to the Schooner Amistad.

Both of these images are taken from The New American Practical Navigator... by Nathaniel Bowditch. (New York: E. & G.W. Blunt Publishers, 1832) Plates VI and VII.

Latitudes and Longitudes of Key Places:

Name of Place     Latitude                 Longitude

Port Lomboko (Mouth of the Gallinas River) 7° 02´ N                 11° 44´ W

Havana, Cuba      23° 09´ N               82° 21´ W

Puerto Principe, Cuba (Chart of 20 Feb. 1775)             21° 40´ N               77° 40´ W

Montauk Point, Long Island, New York, U.S.A.              41° 04´ N               71° 51´ W

Culloden Point, Long Island, New York, U.S.A.             41° 04.3´ N           71° 57.6´ W

New York, New York, U.S.A.              40° 42´ N               74° 01´ W

Cape Verde Islands            16° N      24° W

Freetown, Sierra Leone     8° 30´ N                 13° 18´ W

Exploring Amistad Resources:

Primary Documents:

    Spanish Inventory & Appraisal of the Schooner Amistad (pages 28&29)/ Articles Belonging to the Ship. Pages 28 and 29 of the inventory and appraisal of the Schooner Amistad Items include instruments used for navigation of the ship.

    Rough Draft of Judson's Jurisdiction Decision. There were two central debates in the District Court trial: improper jurisdiction and the freedom of the Africans. This is a rough draft of the decision regarding jurisdiction that Andrew Judson read aloud in Court on January 13, 1840. Part of the argument includes the definition of "high seas" and whether the Amistad was on it or not.

    Nautical Chart of Guanaja, Cuba circa. 1840.

    Nautical Chart of Cuba (1) circa 1840.

    Nautical Chart of Cuba (2) circa 1840.

    Nautical Chart of Havana Harbor, Cuba, circa 1840.

    Nautical Chart of Long Island Sound, New York, U.S.A., circa 1840.

    Nautical Chart of New Haven, Connecticut, U.S.A., circa 1840.

    Nautical Chart of New London, Connecticut, U.S.A., circa 1840.

Student Exercises:

    * Show that the problem of transferring a round earth to a flat chart always has the expense of distorting some features while preserving the accuracy of others.

    * Compare world maps, especially Mercator (where latitude and longitude cross at right angles) with a globe, to see which and by how much, features are distorted.

    * Show how to use the latitude scale of a Mercator Chart for measuring nautical miles. View some sample conversions of degrees and distance.

    * Find and/or plot key places from the Amistad Incident on Defense Mapping Agency chart No. 120 of the North Atlantic Ocean (Southern Sheet), showing both the African and North American coasts. For ordering information of DMA chart No. 120, visit Bluewater Books and Charts or New York Nautical on-line. If this chart is unavailable, a regular world map with latitude and longitude lines will do.

          o Plot rhumb line courses of voyages. A rhumb line is a path taken by a ship that maintains a constant direction.

          o Measure nautical miles between ports.

          o Determine courses between ports.

    * Study ocean currents and prevailing winds on North Atlantic Pilot Charts. The U.S. Navy has some charts available on-line. (Look at the Gulf gifs or files to see the North Atlantic).

    * Calculate the average speed of the Amistad for different sections of its trip.

    * Allow students to develop their own questions and determine locations to answer those questions using the scientific method.

    * Discuss tools needed for navigation. Have students find definitions and explain uses of instruments typically used on ships like the Gentleman. An excellent source for these definitions is The American Practical Navigator by Nathaniel Bowditch.

Build your own instruments!: To find out about how to build your own:

          o Cross-Staff and Calibrator, see the Amateur Scientist section in Scientific American. November 1974, pages 126-128.

          o Astrolabe, check out one of these sites:

            Hands on Astrolabe

            Making a Simple Astrolabe

            Building and Using an Astrolabe

          o Sextant or Quadrant (Octant), check out one of these sites:

            The Quadrant- An Exercise in Error Analysis

            What's Your Latitude?

Discussion Questions:

How could a navigator determine northward (southward) travel? Describe systems and tools of navigation used by different cultures. What factors were involved in the establishment of various Prime Meridians? If the Prime Meridian were to be changed, where would be a good place for it? How can latitude and longitude be determined by the North Star or the noon Sun? How does longitude relate to the difference in time on a ship, determined with a sextant, and time at the Prime Meridian, as determined by a chronometer or Lunar Observation? What was the total distance (in nautical miles, feet, meters, etc.) traveled by the Amistad Africans (don't forget it took 58 days to travel only 1200 nautical miles from Havana to Montauk Point)? What is the shortest distance they could have traveled while still going to every point they did? How does understanding the navigational portion of the Amistad Africans' trip help put their ordeal in perspective?

Conversion:

On a great circle such as the Meridian or the Equator, 1´ =one nautical mile or 1° =60 nautical miles on the part of the latitude scale corresponding to the latitude of the place for which the distance is being measured. A nautical mile in the period of the Amistad was take as equal to about 6120 feet, while in 1998, it is equal to exactly 1852 meters, or about 6076.11 feet.

Contacts: Don Treworgy * This e-mail address is being protected from spam bots, you need JavaScript enabled to view it