After the prize of 20.000 pounds established by the British Parliament in 1714 for someone who would find an exact method of measuring the geographical longitude of a ship on the open sea and the victory of John Harrison’s “chronometers”, the navigation across the oceans changed a lot. However, since even the most exact chronometers erred a few seconds after a long journey, a lot of sea ports decided to have a time-ball (as we saw in Greenwich!) installed on a tower or a lighthouse.
The ball’s fall at noon let the captains adjust their ship’s chronometers before the next voyage.
The Gdansk ball was the first one in the Baltic Sea and it seems to be the only openwork time-ball in the World. It was first constructed in 1876 on the top of a wooden tower which was especially built although it was transferred to the new Nowy Port lighthouse in 1894 (the current location!).
The invention ofradio by Marconi at the turn of the XIX-XX centuries spelled the end of the time-ball era. The first radio station in Gdansk went into service in 1921, and when in 1929 a heavy strom ripped the Gdansk time-ball off the top of the lighthouse, it was never repaired. First in 2008, four years after the lighthouse itself was restored and opened to the public, was the famous Time-Ball reconstructed.
I think I’m going to look for other time-balls in the World. It seems to be very interesting!
Location: The Gdansk Time-Ball in Nowy Port (map)
This astronomical clock was constructed between 1464 qnd 1470 by the clockmaker Hans Düringer of Nuremberg. It’s 14 metres high and was the World’s tallest clock in the 15th century. It was reconstructed after the damages in the Second World War.
The construction of St. Mary began in 1379 and it’s currently the largest brick church in the World because of it’s 105 metres high and the nave is 66 metres wide.
It’s one of the symbols of Gdansk. For example, here you have on German Nazi propaganda poster from 1939 with St. Mary as guest star:
The clock shows the date, the time, the phases and position of the Moon and the position of the Sun in the Zodiac. On the clock Adam and Eve alongside the Three Kings, the Death and the Apostles.
There also are the calendar of the Saints so it’s a very complete clock.
By the way, there is a sundial in one of the lateral facades!
Location: Basilica of St. Mary of the Blessed Virgin Mary in Gdańsk (map)
This is one of the Top 10 Museums in Prague! The museum was founded in 1908 and has been in its current location since 1941. It’s a very big building and the collection exhibited is so big although the exhibition about transports is its main attraction:
But for me, the exhibition about Astronomy has been the interesting part of the museum and I have been able to visit it on my own meanwhile my children were playing in another room with some technical toys. The astronomical rooms are very dark so it has been very difficult to take good pictures although I’ve tried to do my best. The collections has sundials, armilar spheres, quadrants, astrolabes,… and a lot of other astronomical instruments:
For example, the polyhedrical sundials are so beautiful like this constructed on a cube by German David Beringer around 1750:
Or… what about this other constructed by Mathias Karl Krausler in 1691?
The oldest exhibited astrolabe is this unsigned one from around 1450:
And there also is an unsigned torquetum from the late 16th century:
One of the instruments which have surprised me has been Joost Bürgi’s sextant for measuring the angles of celestial bodies (I knew that Bürgi, one of the inventor of logarithms, had constructed a lot of clocks and astronomical instruments but I didn’t expect to find one here!). Kepler used it to measure two consecutive oppositions of the planet Mars in 1602 and 1604.
There also is Habermel’s sextant, built by Erasmus Habermel (1538 – 15th of November of 1606 in Prag) who was mechanic at the court of Emperor Rudolph II:
The prevailing opinion for a long time was that the instrument belonged to Brahe and so it was called the “Tychonian sextant”.
Habermel was specialised in small devices and portable sundials and one example is this sundial in the form of a book (c.1600)…
… and another is this equinoctial sundial (1585):
Finally, look at this armilar sphere from the second half of the 16th century! It’s a piece of art!
This emblematic astronomical clock was first installed in 1410 and it’s the oldest one still working in the World. It’s mounted on the southern wall of the Old Town City Hall and it’s composed of an astronomical dial which represents the position of the Moon and the Sun in the sky and in other celestial coordinates…
…, the “Walk of the Apostles” over it which shows the figures of the Apostles walking in circles each hour while a skeleton representing the Death moves a rope connected to the clock’s bell:
Finally, there is a calendar dial with medallions representing the twelve months:
The clock was made by the imperial clockmaker Mikuláš of Kadaň and the professor Jan Šindel who taught mathematics and astronomy at Charles University in Prague in times of the Emperor Wenceslav IV of Bohemia (emperor from 1376 to 1419). Nowadays, all the people who visit Prague go to the clock to take pictures of it and to see the short Walk of the Apostles in the tower of the Old Town City Hall:
The clock has always been the centre of attraction of this great square as we can see from some ancient pictures. For example, here you have the clock in a drawing by Jan Josef Dietzler from 1743:
And this other picture also by Dietzler:
From 1791 we have this picture by Kaspar Pluth:
So in 1790 the new emperor decided to parade in front of this astronomical clock.
Finally, we have this photography taken around 1870:
Location: Prague astronomical clock (map)
The third step in the visit to the Royal Observatory of Greenwich is Flamsteed House.
The Royal Observatory of Greenwich was founded in 1675 when Charles II ordered that a small observatory be built in Greenwich Park and appointed John Flamsteed as his ‘astronomical observator’. Flamsteed’s task was to make observations that would improve astronomical navigation, in particular providing a means of finding longitude at sea.
The ceiling of the first room is painted with a map of the night sky and there are portraits of the ten Astronomers Royal who lived here between 1676 and 1948:
Christopher Wren was responsible for building the Observatory. He later said that it was designed ‘for the Observator’s habitation & a little for Pompe’. The following four rooms were Flamsteed’s living quarters. They were incorporated into the enlarged home of the Astronomer’s Royal over the next two and a half centuries. Beyond these, upstairs, is the magnificient Great Star Room, or Octagon Room.
The Octagon Room is one of the few surviving interiors designed by Wren and it was used mainly for observing eclipses, comets and other unusual celestial events.
The 32-inch Astronomical Quadrant is located in this room. It is signed by John Bird but the telescope which was once attached is missing.
The engraving of the Octagon Room by Francis Place shows a similar, earlier quadrant standing on a wheel-tripod platform, which allowed the astronomer to roll it from window to window.
On the wall behind the quadrant we can see three replicas of the clocks which were made in 1676 by Thomas Tompion and sold by Flamsteed’s widow some years later. There is also a replica telescope tube of the kind used here until 1765. Will my daughter be able to discover a new planet?
If we go downstairs now we’ll discover an exhibition about the determination of the longitude at sea:
Where am I?
At sea, navigation is a matter of life and death. Out of sight of land, how can you tell where you are?
By 1700, skilled seamen could find their position north or south (their latitude), but still lacked accurated instruments or methods to calculate their east-west position, known as longitude.
With growing international trade, the lives and valuable cargoes lost in shipwrecks made solving this ‘Longitude Problem’ urgent for all sea-going nations.
The exhibition starts with these two 17th-century globes from North Africa (left) and Persia (right) and then you meet the star of the ‘Longitude Problem’:
Finding longitude – the timekeeper method
One solution to the Longitude Problem was an accurate and portable sea-going clock. By 1726, news of the Longitude Prize had reached John Harrison, a carpenter and self-taught clockmaker from Lincolnshire. Harrison was already making highly accurate land-based clocks and had solved major problems to do with temperature change and friction.
Harrison spent the next 45 years of his life developing portable sea-going timekeepers that would accurately, in spite of a ship’s motion and temperature changes. Each timekeeper represented years of obsessive labour.
By 1760, Harrison had solved the Longitude Problem with his fourth marine timekeeper, now known as H4. It is one of the most important machines ever made.
Harrison’s first timekeeper [H1]
This timekeeper took five years to build. In 1736, it was tested on a sea voyage to Lisbon and back. Harrison was very seasick, but the timekeeper worked. It was the most accurate sea-going clock then known, though not quite accurate enough to win the 20.000 pounds prize.
This prize was offered in 1734 by the British government for a ‘practical and useful’ method enabling ships to determine their longitude at sea.
In the exhibition there are also some timekeepers more and the portraits of some of the most important scientific men which lived in the same time as Harrison: Halley succeeded Flamsteed as Astronomer Royale and his major programme was to replace all the astronomical instruments which were sold by Flamsteed’s widow, and to chart the Moon’s 19-year cycle.
Newton advised the Parliamentary committee that established the Longitude Prize and became a member of the Board of Longitude:
Finally, apart of the camera obscura, we can find outside the Family Tombstone of Halley which was moved to the Observatory from the churchyard of St. Margaret’s in Lee when Halley’s tomb was restored in 1854. The tomb itself is still located at St. Margaret’s with a replica tombstone in place:
As you have seen, you must visit the Royal Observatory in Greenwich if you visit London: it’s only a few metro stops from the center of the city!
The Royal Observatory of Greenwich was commisioned in 1675 by Charles II and the building was completed in the summer of 1676. John Flamsteed (1646-1719) was the first Astronomer Royal so the building was often given the title “Flamsteed House” in reference to its first occupant.
In one of the walls, the observatory has the Sepherd 24-hour Gate Clock which is the earliest electrically driven public clocks. It was installed in 1852 ans the dial always shows Greenwich Mean Time (GMT):
In the small plate under the clock (G 1692) is an Ordnance Survey bench mark dating from the 1940s. The height above the sea level has been measured and recorded. There are also the British Imperial Standards of Length which were mounted here some time before 1866.
The observatory is also known as the location of the prime meridian of Greenwich meridian:
All the tourist want to have a picture with a foot in each side of the meridian:
and there is always a large queue to take a picture next to the meridian line which is graved ion the terrace:
Another characteristic thing of the obervatory is the Time Ball. The red time ball on top of Flamsteed House is one of the world’s first visual time signals. It was installed in 1833 to enable navigators on ships in the Thames to check their marine chronometers.
The Time Ball drops daily at 13:00hrs (GMT in winter […]). It is raised halfway up the mast at 12:55hrs as a preparatory signal and to the top 2 minutes before it drops.
Let’s start our visit through the gardens of the observatory where we can imagine the great English astronomers looking at the night sky! Ofcourse we find a sundial:
Sundials are the oldest known device for telling the time. As the Earth rotates and the Sun appears to move accross the sky, the shadow cast on the scale indicates the time of the day.
This dial constructed in 1968, represents a globe made from a series of rings. The rings are called ‘armillae’ in Latin, so it is called an armillary dial. The hour scale is on the northern half of the ring representing the equator.
There is also the well where Flamsteed 100-foot telescope was located:
Flamsteed used a 30,5 m. well on this site to accomodate a very long telescope:
The astronomer sat at the bottom of the well and observed stars that passed directly overhead. It was hoped that placing the telescope in the well would make it possible to create a steady long-focus instrument for very fine measurements. Flamsteed made a few observations from here in 1679, but the damp underground conditions soon made the telescope impossible to use.
A remaining section of a 12 m. reflecting telescope built for the astronomer William Herschel is also in the gardens:
The telescope was the largest in the world and cost over 4.000 pounds, paid for by King George III. Completed in 1789 and erected at Herschel’s home near Slough, about 30 miles (48 km) west of Greenwich, it soon became a tourist attraction. Some people likened it to the Colossus of Rhodes, and it was even marked on the 1830 Ordnance Survey map of the area.
Sadly, the Herschels did not use the great telescope for much serious astronomy since it was difficult to set up and mantain. William’s son had it dismantled in 1840. Most of the tube was destroyed when a tree fell on it 30 years later.
On the walls of Flamsteed House is marked the Bradley Merdian which was the first British National Meridian. The Greenwich meridian was set according to the location of the telescope used by the Astronomer Royal to establish the time. So the Greenwich meridian was in the graved line when James Bradley, the 3rd Astronomer Royal between 1742 and 1762 was in the observatory. When the Airy Transit Circle Telescope was erected in 1850, the Greenwich Meridian was moved approximately 19 feet east to its present location.
Before visiting Flamsteed House there is still time for look at the Dolphin Sundial designed by Christopher St. J. H. Daniel and commisioned by the National Maritime Museum in 1977:
So let’s go now to Flamsteed House!
The Pitt Rivers Museum cares for the University of Oxford’s collection of anthropology and world archaeology. It is next to the Oxford University Museum of Natural History which was closed in August and it was very surprising for me and also for my kids (I think it’s an idela museum for children!).
There are some interesting mathematical objects in the collection and I am going to list some of them. First of all, we must focus our interest in the showcase dedicated to “counting”:
There are some old counting strings:
and this “swampan”:
“Swampan” or calculating board with sliding beads, used in casting accounts. The two upper balls on each bar = 5 each, the lower balls = units, similar to the roman abacus. China.
There also is the typical “soroban” which is next to a icture of a Roman abacus and in the upper right corner of the next picture:
“Soroban” or calculating board for casting accounts, similar to and derived from the Chinese “swampan”. Japan.
There is also a picture of a “quipu”.
There also are astrolabes and clocks. For example, there are a brass astrolabe dated in 1673 and sme interesting portable sundials:
Finally there is some showcases dedicated to games, dice, chess,… in the upper floor:
Before finishing this post, look at the next picture and try to guess who is this great man:
The Oxford University Museum of Natural History was closed but it was possible to walk around the inner yard and it was possible to see one of the famous statues dedicated to the great scientific men. So it was possible to take a photography of Gottfried Wilhelm Leibniz!
Wells Cathedral is one of the most wonderful cathedrals in South England. We went thenre after visiting the Sonehenge so maybe we couldn’t admire it because of the emotion lived in the morning.
There is a beautiful astronomical clock inside the cathedral:
The clock has 24 marks for each hous of the day and it is a hole through which you can see the Moon phase:
You can also see spheres fot the day of the month and the minutes of the hour. In each hour, the clock has a carillon which is very curious: the wooden man which is sitting in the upper right corner of the second photography rings the bell while two wooden knights over the clock fight in a duel.
Today is Christiaan Huygens’s birthday and this is the doodle dedicated to Huygen’s birthday in April 16, 2009.
Huygens (1629-1695) as one of the first mathematicians to study Probability. He published his De ratiociniis in ludo aleae in 1656 in which he established the foundations of the Calculus of Probabilities after Pascal and Fermat’s letters. Furthermore, he worked on the cycloid, the rectification of curves, the pendulum,…
He also made important contributions to Phisics and Mechanics.
The Royal Palace of Madrid isn’t a mathematical place. Today I have visited it but I haven’t found mathematics in the interesting tour through its rooms. The palace was built by Philip V of Spain on the site of a former palace which was partially destroyed by the fire in 1734. The first Spanish king who lived in the palace was Charles III (Philip V’s third son) and Charles IV, Joseph Bonaparte, Ferdinand VII, Elisabeth II, Alfonso XII and Alfonso XIII also lived here.
I must recognize that I couldn’t leave the Royal Palace without getting a picture to write this post and finally I’ve got two “astronomical” details that justify these sentences. The first one is located on the facade of the palace and it’s an explicit reference to the horoscope:
The other interesting object is a clock which can be found in the small Porcelain Room next to the room where the king Charles III died in 1788: there is a wonderful clock representing Atlas holding the World:
And that’s all! Tomorrow I’m comig back to Barcelona but I’m sure that I’m going to talk about Madrid for some days.
Location: Royal Palace of Madrid (map)