3. the Harrison clocks are at the National Maritime Museum in Greenwich. They are functional, but are kept unwound in order to avoid wear-and-tear.
-----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Sent: Monday, July 10, 2000 10:15 AM To: sundial@rrz.uni-koeln.de Subject: "Longitude" miniseries Hello All: Last night the four hour long TV miniseries, "Longitude" was shown on A&E channel (in US). This fabulous program detailing the struggles of Harrison to perfect a mariners clock and win the prise for determining the longitude at sea should not be missed by anyone who is interested in the history of time, clocks, or engineering. I have a couple of questions about its contents. 1. In the scenes showing the meetings of the Longitude Board with Harrison, on the wall is a large round map of northern Europe with London at the center. Around the perimeter of the map are the cardinal points of a compass. A single moving metal hand is attached at the center. I'm wondering is this might be a mechanical device attached to a weathervane used to indicate the direction of the wind. Or it might be some sort of indoor sundial which shows the sun's hour angle. Does any body have a clue what this instrument does? 2. To determine longitude at sea, Harrison's clock was carried on board a ship traveling west. The clock was set before the journey to show apparent solar time in Greenwich. The difference between local solar time on the ship and the time on the clock was used to determine longitude. To determine local solar time on the ship, Harrison used a sextant to look at the sun. How can a sextant, by itself, indicate the time? To determine high noon, wouldn't he only need a compass to know when the sun "souths" at high noon? 3. Where are the four Harrison clocks today? Are they still functional? Thanks John Carmichael Tucson Arizona
