The photos below are what we saw.
clipper Cutty Sark is docked at Greenwich. Built in 1869
it represented the pinnacle of British sailing technology and
held the record for fastest ship afloat for ten years.
After the Suez Canal opened, steam power took over and the Sark
came to dominate the sailing route to Australia. Given
more time, we would have loved to tour the ship.
walking route to the observatory passed the Maritime Museum and
this nice statue. We were pressed for time, so we did not
stop to investigate.
ship in the bottle is a scale model of Nelson's command
ship. The odd sail fabric is "artistic license".
We saw a
few of these food trucks in the London area. I think the
French made the truck in the 1950s and now they serve as rolling
surprised by the continual jet noise but it turns out that
Greenwich is on the flight path for Heathrow.
that houses the observatory provides a commanding view of the
Canary Wharf area of metropolitan London.
is all about telling time and location. To know your
location, you must know your local time. Time is
referenced to the sun, but knowing time is key to calculating a
ship's location. Failure to have a good fix on ship's
location results in wrecks. After a number of tragic
wrecks with large losses of life and money, the British Admiralty
sought to solve the problem once and for all. The Royal
Observatory was part of that solution plan.
distance measures is critical for both location certainty and
repeatability in the construction processes for ships.
solar noon was measured at the observatory and communicated to
the outside world by dropping this red ball exactly at
noon. The sailors down in the flats on the River Thames
would synchronize their ship's clocks to the dropping of the
ball before heading out to sea.
on this monument points at the center of the earth's
rotation. The Prime Meridian, the zero point for
measurement of longitude, runs along the steel line in the patio
and through the center of the spike.
when local noon occurs is useful, but to make that measurement
something more than a curiosity, you must be able to interpolate
time between successive noons. So, an accurate clock is
needed. Greenwich had many fine examples of old attempts
at building a precision measurement tool for time.
these two clocks were used by staff at the observatory to
measure the movements of the stars in an attempt to provide a
better way to locate a ship's position on the high seas.
large grandfather-style clocks kept reasonable time on
shore. But on the open seas, the rolling of the ship
destroyed the accuracy of the timing. The Admiralty
commissioned a contest to build an accurate timepiece that could
handle shipboard travel. The first attempt was John
Harrison's H-1 clock. The H-1 used counter-oscillating
masses to make it more resistant to ship's motion. And,
the H-1 was independent of the direction of gravity. Over
the years, Harrison's clocks got better and better, but still
eluding the huge reward for the challenge. In essence, the
Admiralty attempted to stiff him and Harrison petitioned the
King to get payment -- which he got. His efforts were an
important factor in Britain establishing naval superiority and
holding it for so many years. See
the Royal Observatory's page on this fascinating story.
other clock designs were built and tested, but none so
transformatory as the Harrison line.
a clock tower mechanism used to move the hands on large clocks.
in the museum was up and they ran us out. To return to
London, we had to take the Docklands Light Rail under the
Thames. The drill bit used to bore the tunnel was on
display at the station.
sections of concrete were installed to make the final tunnel
lining. The lining can be seen in the photo above.
north side of the Thames, we could see some newer structures
including this cool bridge.
Docklands and the Canary Wharf used to host a huge amount of
shipping. These dock cranes were left over from that era
and are now monuments.
significant trip, we ended up back at Blackfriar's station and
back on the street. It was rush hour and the ubiquitous
double-decker buses were out in force.
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Photos and Text Copyright Bill Caid 2015 all rights
For your enjoyment only, not for commercial use.