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Michelle Mendez Caitlin Roberts John Dee- “The art of Navigation demonstrates how, by the shortest good way, by the aptest direction, and in the shortest time, a sufficient ship between any two places assigned, may be conducted, and in all storms and natural disturbances chancing, how to use the best possible means, whereby to recover the place first assigned.” The country that could come up with the newest techniques were better off New colonies Natural resources Pedro Nunez (1537) Loxodromes or latitudes were straight Meridians or Longitudes converged (spiral terminating at pole) Gerard Mercater Mercater’s projection Parallel’s and meridians represented by straight lines (compensated by increased spacing at poles) Because parallels and meridians were straight navigators could use straight edge on a map between origin and destination to determine compass bearing. No mathematical justification 1599 Ratio of length of a degree of longitude at latitude Ø to one at the equator is equal to cosØ Degree of longitude @ Latitude Ø = cosØ Degree of longitude @ Latitude equator (if meridians are straight) Distances between meridians @ Lat. Ø stretch by factor of Sec Ø Could navigator’s apply maps to actually being out in the sea???? How can a ship determine how far East or West it is from its origin?? For every 15° one travels Eastward, local time moves one hour ahead. Similarly, 15° Westward moves one hour back If we know local times in 2 places at one given time, we can tell how far apart they are Navigator’s could measure time by sun, but required time at reference point http://www.youtube.com/watch?v=y6w5Q7tRX88&fea ture=related Columbus attempted Longitude 1494 using Eclipse 1675 King Charles II founded Royal Observatory to find solution Needed a way to tell time in two different locations at same time If accurate catalog of position of stars made and measure accurately the position of the Moon, then Moon’s motion could be natural time keeper to calc. Greenwich time Sailors used combination of measure of position of moon relative to stars and tables of moon’s positions in Royal Observatory to get time at Greenwich. 1707, four British war ships ran aground. 1714 British Gov. offered £ 20,000 ($12,000,000) for method to determine longitude John Harrison- very little formal education Clockmaker 1730-1735 portable version of Harrison’s wooden clock (H1) Tested trip on Centurion and Orford Kept time accurately only lasts for 1 day Asked Board of Longitude for money H2- 1737 Heavier than H1 1740- realized wrong design and bar balances did not always counter motion of ship H3 Bimetallic strip to compensate the balance spring for effects of changes in temp. Caged roller bearing- ultimate version of antifriction 1755 Hired John Jeffreys to help make a pocket watch for personal use for astronomical testing 13 cm in diameter and 1.45 kg Trial 1 • Harrison’s son sailed to W. Indies on Deptford estimated time was only 5.1 sec. off Trial 2 Barbados to Madeira error 39.2 over 47 days Three times better than time required to win prize Board of Longitude wouldn’t accept H4 was legitimate Required that Harrison make two more copies himself and have someone else create their own model of H4 to prove not a fluke Original H1-H4 sent to Royal Observatory to be studied and tested Appointed Larcum Kendall to make his own construction Harrison made H5 while Kendall made copy of H4 also called K1 1769 Asked board since both models worked, could be the two extra models of H4 Appealed to King George III at 79 Private Interview with King “…These people have been cruelly wrong…By God Harrison, I will see you righted!!” H5 trialed by King Board refused to recognize results Petitioned parliament 1773 recognized as solving longitude problem