GREENWICH and
the GREENWICH MERIDIAN
When Galileo was put under
house arrest for his scientific activities, the tide of enquiry in the
field of natural philosophy moved north of the Alps to the Protestant
maritime nations, chiefly Holland and England.
During the next 50 years, Newton and other luminaries made enormous contributions
to the way people viewed the world, in fact it was in this period that
the Royal Society was sponsored by Charles II as a venue for the exchange
of new ideas.
This coincided with the expansion of trade by the maritime nations in
opposition to the Spanish and Portuguese powers and the defeat of Louis
XIV on the continent by the Duke of Marlborough.
During the 18th century Britain emerged
as a dominant sea power and this led to a wide flung empire which needed
a state of the art navy. For this, they needed a sure and certain way
to determine the exact location of ships at sea.
One of the main navigational problems faced by mariners was the difficulty of determining an accurate value for longitude, which was needed to find the location, in the east-west direction, of any position at sea..
This problem was graphically illustrated by the disaster of Sir Cloudesly Shovell when he ran aground on the Scilly isles due to a navigational error - they though they were close to the coast of France. Sad to tell, the local population looted the wrecks and killed any crew that made it to the shore.
The Greenwich Observatory and the other buildings there were built in the second half of the seventeenth century by Christopher Wren under the patronage of Charles II and were initially a palace as well as an observatory.
The idea of a zero-degree longitude was first proposed by Flamsteed, the first Astronomer Royal, in about 1680, followed by Halley and then by Bradley in the mid 1700's. The latter line was used by the ordinance survey in it's maps.
The line shown in the picture is due to yet another Astronomer Royal, Sir George Airy, whose line was accepted internationally in 1884.
These various lines were of no practical use Benjamin Harrison developed a reliable time piece capable of establishing the time at the Greenwich Meridian. (The difference between this time compared to that of a ship in mid-ocean was, and is, necessary to establish it's position.)
This achievement took forty years to bring about and Harrison received 20,000 pounds for his services in about 1780, though it required the intervention of King George himself to get the payment made. A good investment in view of the Napoleonic wars which followed in the early 1800's.
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