Showing posts with label Galileo. Show all posts
Showing posts with label Galileo. Show all posts

25 October 2016

Evangelista Torricelli – inventor of the barometer

Physicist's name lives on in scientific terminology

Evangelista Torricelli: a portrait by Lorenzo Lippi, shortly before he died
Evangelista Torricelli: a portrait by
Lorenzo Lippi, shortly before he died
The inventor of the barometer, Evangelista Torricelli, died on this day in 1647 in Florence at the age of just 39.

A disciple of Galileo, Torricelli made many mathematical and scientific advances during his short life and had an asteroid and a crater on the moon named after him.

Torricelli was born into a poor family from Faenza in the province of Ravenna.

He was given a basic education in Faenza and then sent to a Jesuit college to study Mathematics and Philosophy.

He studied science under the Benedictine monk, Benedetto Castelli, a professor of Mathematics at the Collegio della Sapienza, now known as the Sapienza University of Rome, who had been a student of Galileo Galilei.

Torricelli also became an admirer of Galileo and, after the great scientist’s Dialogues of the New Science were published, Torricelli wrote to him telling him he had read it with ‘delight’.

Galileo was condemned by the Vatican in 1633 for his beliefs and held prisoner at his villa in Arcetri. For the last three months of Galileo’s life, Torricelli worked for him there as his secretary and assistant.

Early barometers based on Torricelli's findings
Early barometers based on
Torricelli's findings
After Galileo’s death the Grand Duke Ferdinand II de Medici asked Torricelli to succeed Galileo as Chair of Mathematics at the University of Pisa.

In this role Torricelli solved some of the great mathematical problems of the day and described his observations in his book, Opera Geometrica. His work contributed to the eventual development of integral calculus.

Torricelli was also interested in optics and designed and built telescopes and microscopes.

But his most important invention was the mercury barometer, which he produced after he had discovered the principle of the barometer while trying to find a solution to the limitations of the suction pump in forcing water upwards.

He designed a kind of vacuum pump using mercury. He filled a metre-long glass tube, closed at one end, with mercury and inverted the tube so that the open end rested on the bottom of a vessel containing more mercury.  The mercury in the tube fell until it reached the point at which the weight of the mercury in the tube was balanced against the pressure exerted by air on the mercury in the vessel, leaving a vacuum at the top of the tube.

The statue of Torricelli in Faenza
The statue of Torricelli in Faenza
Torricelli noted that the height of the mercury in the column varied from day to day, which he concluded was due to changes in atmospheric pressure. In 1644, he turned these discoveries into the first instrument to measure atmospheric pressure.

Scientific terms such as the Torricellian tube and Torricellian vacuum are named after the scientist, as is the torr, a unit of pressure in vacuum measurements. Torricelli’s Law refers to the speed of a fluid flowing out of an opening and Torricelli’s Trumpet relates to mathematical discoveries he made about infinity.

Torricelli died in Florence ten days after his 39th birthday and was buried at the Basilica of San Lorenzo.

Several Italian submarines have been named after Torricelli in honour of his work.

Travel tip:

A statue of Torricelli was erected in 1868 in Faenza, the city where he was born and educated, in recognition of all he had done to advance science during his short lifetime. The white marble statue can be found in the park of San Francesco in Corso Giuseppe Garibaldi.

An example of faience majolica-ware
An example of faience majolica-ware
Travel tip:

Faenza is in the Emilia-Romagna region, about 50 kilometres south east of Bologna. The city is famous for the manufacture of a type of decorative majolica-ware known as faience. It is also home to the International Museum of Ceramics, which has examples of ceramics from ancient times, the Middle Ages and the 18th and 19th centuries as well as displaying work by important contemporary artists. The museum is in Viale Baccarini in Faenza. For more information visit

More reading:

(Picture of faience plate by Rosco CC BY-SA 2.5)


21 September 2016

Cigoli – painter and architect

First artist to paint a realistic moon

Cigoli's fresco at the Church of Santa Maria Maggiore shows  the Madonna standing on a pock-marked crescent moon
Cigoli's fresco at the Church of Santa Maria Maggiore shows
 the Madonna standing on a pock-marked crescent moon
The artist Cigoli was born Lodovico Cardi on this day in 1559 near San Miniato in Tuscany.

He became a close friend of Galileo Galilei, who is said to have regarded him as the greatest painter of his time. They wrote to each other regularly and Galileo practised his drawing while Cigoli enjoyed making astronomical observances.

Cigoli painted a fresco in the dome of the Church of Santa Maria Maggiore in Rome depicting the Madonna standing upon a pock-marked lunar orb, exactly as it had been seen by Galileo through his telescope.

This is the first example still in existence of Galileo’s discovery about the surface of the moon being portrayed in art. The moon is shown just as Galileo had drawn it in his astronomical treatise, Sidereus Nuncius, which published the results of Galileo’s early observations of the imperfect and mountainous moon.

Until Cigoli’s fresco, the moon in pictures of the Virgin had always been represented by artists as spherical and smooth.

Cigoli's Martyrdom of St Stephen is in the Uffizi Gallery in Florence
Cigoli's Martyrdom of St Stephen is in
the Uffizi Gallery in Florence
Lodovico Cardi was born at Villa Castelvecchio di Cigoli, and was therefore commonly known as Cigoli.

He trained as an artist in Florence under the Mannerist painter Alessandro Allori. But he later discarded Mannerist principles and painted to express his own feelings and ideas.

Cigoli also worked with the architect Bernardo Buontalenti in Florence and the imposing inner courtyard of the Palazzo Nonfinito in the city is believed to have been designed by Cigoli.

He painted a version of Ecce Homo for a Roman patron, which was subsequently taken by Napoleon to the Louvre in Paris. It was later restored to Florence and can now be seen in Palazzo Pitti.

Also for the Pitti Palace, Cigoli painted a Venus and Satyr and a Sacrifice of Isaac.

He became so famous and admired that when he travelled to Rome he was personally welcomed and greeted by the Florentine ambassador to the city.

For St Peter’s in Rome, Cigoli painted St Peter Healing the Lame. For the Church of San Paolo fuori le mura, he painted an unfinished Burial of St Paul. In a fresco for the Villa Borghese he painted a Story of Psyche.

Among other important Cigoli paintings are his Martyrdom of St Stephen and Stigmata of St Francis, which are both now in the Uffizi Gallery in Florence.

Just before Cigoli’s death in Rome in June 1613 he was made a Knight of Malta by Pope Paul V.

The statue of Lodovico Cardi in his home village of Cigoli in Tuscany
The statue of Lodovico Cardi in his home
village of Cigoli in Tuscany
Travel tip:

Villa di Castelvecchio di Cigoli, the artist’s birthplace, is now referred to simply as Cigoli and is a hamlet - frazione - of the town of San Miniato in the province of Pisa in Tuscany. The Bishop’s Sanctuary in San Miniato has a Baroque façade designed by Cigoli.  There is a statue of Lodovico Cardi outside the Santaurio della Madonna Madre dei Bambini. San Miniato is also famous for white truffles and during the last three weeks of November hosts a festival dedicated to the white truffle, which is harvested in the surrounding area and is more highly valued than the black truffles found in other regions of Italy.

Travel tip:

After Cigoli’s death in Rome in 1613, his remains were transferred to Florence and buried in the Church of Santi Michele Arcangelo and Gaetano da Thiene in Via de Tornabuoni. The Church is one of the most important examples of the Baroque style of architecture in the city. Cigoli’s family tomb is between the second and third chapel on the left.

(Photos of Martyrdom of St Peter and statue by Sailko CC BY 3.0)


14 July 2016

Collapse of St Mark’s Campanile

Dramatic fall of instantly recognisable symbol of Venice

An enormous pile of rubble was left after the collapse of the Campanile in July 1902
An enormous pile of rubble was left after the collapse
of the Campanile in July 1902
The bell tower (Campanile) in St Mark’s Square in Venice collapsed on this day in 1902.

No one was killed but the Biblioteca Marciana nearby was partially damaged by its fall.

A crack had appeared in one of the walls of the bell tower a few days before and at approximately 9.45 am on Monday, 14 July, the entire structure collapsed into a heap of rubble.

Venetians regarded the event as a tragedy. The bell tower, just short of 100 metres tall, had stood for around 1,000 years and was seen as symbolic of the city.  Built on foundations of wood and mud, however, there was always the danger it would become unstable over time.

On the evening of the day of the collapse, the Venice authorities approved funding for the reconstruction of the Campanile in exactly the same place in the piazza, to be built to resemble how it looked after 16th century improvements to the original ninth century design.

The rubble was painstakingly removed from the square, loaded on to barges and dumped in the sea about five miles offshore from Venice Lido.

The new tower was designed with internal reinforcement to prevent a future collapse, and a lift.

The rebuilding of the Campanile took nearly ten years and the new bell tower was finally inaugurated on 25 April, 1912 on St Mark’s feast day.

The Campanile in Venice today
The Campanile today
Travel tip:

Magnificent panoramic views across Venice and the lagoon can be enjoyed from the top of the Campanile, which is open to the public every day from 09.30 to 19.00. Galileo would have seen these views when he demonstrated his telescope to the Doge of Venice from the top of the previous bell tower in 1609.

Travel tip:

St Mark’s Square (Piazza San Marco) has been the scene of countless pageants, processions, political activities and Carnival festivities during its long history. Thousands of tourists flock to it every day to visit the Basilica and the Doge’s Palace, or to listen to the musicians playing outside the elegant cafes on each side.

Situated close to the lagoon, the Piazza is usually one of the first points in the city to suffer from flooding when there is a high tide (aqua alta).

More about Venice:

The composer Albinoni

The painter Tintoretto

The adventurer Casinova


24 May 2016

Gian Gastone de' Medici – Grand Duke of Tuscany

The last Medici to rule Florence

Portrait of Gian Gastone de' Medici
A portrait of Gian Gastone de' Medici,
the last in a line of Florentine rulers
Gian Gastone de' Medici, the seventh and last Grand Duke of Tuscany, was born on this day in 1671 in the Pitti Palace in Florence.

He was the second son of Grand Duke Cosimo III and Marguerite Louise d’Orleans.

Because his elder brother predeceased him he succeeded his father to the title in 1723.

He had an unhappy arranged marriage and the couple had no children so when he died in 1737 it was the end of 300 years of Medici rule over Florence.

He spent the last few years of his reign confined to bed, looked after by his entourage.

One of his final acts was to order the erection of a statue to Galileo in the Basilica of Santa Croce.

He was buried in the Basilica of San Lorenzo and Francis Stephen of Lorraine succeeded to the title of Grand Duke of Tuscany.

Travel tip:

The Palazzo Pitti, known in English as the Pitti Palace, is on the south side of the River Arno, a short distance from the Ponte Vecchio. It became the main residence of the rulers of the Grand Duchy of Tuscany and is now the largest museum complex in Florence.

Photo of the Museo Galileo
The Museo Galileo in Piazza dei Giudici houses one of the
world's biggest collections of scientific instruments
Travel tip:

There is a museum dedicated to Galileo in Florence, the Museo Galileo in Piazza dei Giudici close to the Uffizi Gallery. It houses one of the biggest collections of scientific instruments in the world in Palazzo Castellani, an 11th century building. The museum is open Mondays to Sundays from 9.30 to 18.00, closing at 13.00 on Tuesdays.

(Photo of the museum courtesy of Museo Galileo CC BY-SA 3.0)

12 May 2016

Cosimo II de' Medici - patron of Galileo

Grand Duke of Tuscany maintained family tradition

Portrait of Cosimo II de' Medici
Cosimo II de' Medici
Born on this day in Florence in 1590, Cosimo II de' Medici, who was Grand Duke of Tuscany from 1609 until his premature death in 1621, was largely a figurehead ruler during his 12-year reign, delegating administrative powers to his ministers.

His health was never good and he died from tuberculosis aged only 30 yet made his mark by maintaining the Medici family tradition for patronage by supporting the astronomer and physicist Galileo Galilei.

Galileo, from Pisa, had been Cosimo's childhood tutor during the time that he was Professor of Mathematics at the University of Padua.

From the beginnings of the Medici dynasty, with Cosimo the Elder's rise to power in 1434, the family supported the arts and humanities, turning Florence into what became known as the cradle of the Renaissance.

Cosimo the Elder gave his patronage to artists such as Ghiberti, Brunelleschi, Donatello and Fra Angelico.  His grandson, Lorenzo the Magnificent, supported the work of such Renaissance masters as Botticelli, Leonardo da Vinci and Michelangelo.

Galileo, who also had the patronage of Cosimo's eldest son and heir, Ferdinando II de' Medici, dedicated his treatise Sidereus Nuncius, an account of his telescopic discoveries, to Cosimo. Additionally, Galileo christened the moons of Jupiter the 'Medicean stars'.

Cosimo II was the elder son of Ferdinando I de' Medici, the third Grand Duke of Tuscany, and Christina of Lorraine. Ferdinando arranged for him to marry Archduchess Maria Maddalena of Austria, daughter of Archduke Charles II, in 1608. Together they had eight children, among whom was Cosimo's eventual successor, Ferdinando II, an Archduchess of Inner Austria, a Duchess of Parma and two cardinals.

After he died at the family home at the Palazzo Pitti in Florence, in 1621, the power of Florence and Tuscany began a slow decline.  When the last Medici grand duke, Gian Gastone, died without a male heir in 1737, the family dynasty died with him.

Photograph of the Palazzo Pitti in Florence
The facade of the Palazzo Pitti in Florence, former
family home of the Medici dynasty
Travel tip:

The Palazzo Pitti, known in English as the Pitti Palace, is situated on the south side of the River Arno, a short distance from the Ponte Vecchio. It was originally the home of Luca Pitti, a Florentine banker, and was bought by the Medici family in 1549, after which it became the chief residence of the ruling families of the Grand Duchy of Tuscany. It is now the largest museum complex in Florence, housing eight museums and galleries.

Travel tip:

The Museo Galileo in Florence is in Piazza dei Giudici close to the Uffizi Gallery. It houses one of the biggest collections of scientific instruments in the world in Palazzo Castellani, an 11th century building.

More reading: 

Galileo Galilei, the founder of modern science

Grand designs of Cosimo I

Medici patronage behind invention of piano


5 April 2016

Vincenzo Viviani – mathematician and scientist

Galileo follower's name lives on as moon crater

This portrait of Viviani is owned by Nice Art Gallery
Vincenzo Viviani
Forward-thinking scientist Vincenzo Viviani was born on this day in 1622 in Florence.

Viviani worked as an assistant to Galileo Galilei and after his mentor's death continued his experimental work in the field of mathematics and physics. This work was considered so important that Viviani has had a small crater on the moon named after him.

While at school in Florence, Viviani was given a scholarship to buy mathematical books by the Grand Duke Ferdinando II de' Medici. He later became a pupil of Evangelista Torricelli and worked with him on physics and geometry.

By the time he was 17 he was working as an assistant to Galileo Galilei. After Galileo’s death in 1642, Viviani edited the first edition of his teacher’s collected works.

Viviani was appointed to fill Torricelli’s position at the Accademia dell’Arte del Disegno in Florence after his death in 1647.

In 1660 Viviani conducted an experiment with another scientist, Giovanni Borelli, to determine the speed of sound by timing the difference between seeing the flash and hearing the noise of a cannon being fired from a distance.

As his reputation as a mathematician grew, Viviani started to receive job offers from abroad. As a result the Grand Duke offered him a post as court mathematician in order to keep him in Italy.

Viviani had published a book on engineering and had almost completed a major work on the resistance of solids when he died in Florence in 1703 at the age of 81.

Viviani decorated his home with an elaborate facade paying tribute to Galileo
The extraordinary façade of Vincenzo Viviani's former home
in Florence, with a bust of Galileo over the entrance
(Photo: Jebulon CC0 1.0)
Travel tip:

Palazzo dei Cartelloni, formerly known as Palazzo Viviani, in Via Sant’Antonino in Florence, has prominent inscriptions on the façade in Latin celebrating and glorifying the life and discoveries of Galileo Galilei. Viviani had these applied to the front of his home as a tribute to his mentor and there is also a bust of Galileo over the entrance. Today the building is owned by an American art institution.

Travel tip:

Galileo’s tomb in the Basilica of Santa Croce in Florence was not erected until 1737 when his remains were finally allowed a Christian burial. With the help of money left by Viviani in his will for a tomb for himself and Galileo, the scientist was reburied below a bust of himself by Giovanni Battista Foggini. Viviani’s own remains were transferred to the grave at the same time, according to his wishes.

Read more:


15 February 2016

Galileo Galilei – astronomer and physicist

Scholar has been judged to be the founder of modern science 

A portrait of Galileo Galilei painted
in 1636 by Justus Sustermans 
Renaissance scientist Galileo Galilei was born on this day in 1564 in Pisa.  He was an astronomer, physicist and engineer and has been called the father of observational astronomy and of modern science.

His astronomical observations, made with the help of telescopes he designed and engineered himself, confirmed the phases of Venus, discovered the four largest satellites of Jupiter and analysed sunspots. He cannot be credited with inventing the telescope, his own having come later than one patented in Holland, although he was certainly a pioneer of its development. Among Galileo's other inventions, however, the military compass is accepted as solely his.

Controversy marred Galileo's later life. His astronomical observations and other aspects of his scientific knowledge led him to support the view of the Polish scientist Nicolaus Copernicus in the previous century that the sun rather than the earth was the centre of the solar system.

This led to his trial and conviction by the Roman Catholic Inquisition as a heretic. He avoided being burned at the stake by reluctantly recanting the statements he had made in a publication on the subject but spent the last 10 years of his life under house arrest at his villa at Arcetri, south of Florence. 

Galileo was educated at a monastery near Florence and considered entering the priesthood but he enrolled instead at the University of Pisa to study medicine.

In 1581 he noticed a swinging chandelier being moved to swing in larger and smaller arcs by air currents. He experimented with two swinging pendulums and found they kept time together although he started one with a large sweep and the other with a smaller sweep. It was almost 100 years before a swinging pendulum was used to create an accurate timepiece.

Two of Galileo Galilei's early telescopes, which are kept at the Museo Galileo in Florence
Two of Galileo Galilei's early telescopes, which
are kept at the Museo Galileo in Florence
He talked his father, Vincenzo, a noted lutenist and composer, into letting him study mathematics and natural philosophy instead of medicine and by 1589 had been appointed to the chair of Mathematics at Pisa.

He moved to the University of Padua where he taught geometry, mechanics and astronomy until 1610. His interest in inventing is thought by some historians to have been driven by family circumstances. After the death of their father, Galileo's younger brother, Michelangelo or Michelagnolo, who also became a lutenist and composer, was financially dependent on his older sibling, who saw the invention and patenting of new devices as a way to generate extra income.

During his own lifetime and subsequently, Galileo tended to be referred to by his first name only, as was common during the 16th and 17th centuries in Italy. He is thought to be related to Galileo Bonaiuti, an important physician, professor, and politician in Florence in the 15th century.

Galileo's appearance before the Inquistion led to him being threatened with being burnt at the stake
Galileo's appearance before the Inquistion led to
him being threatened with being burned at the stake
Like Galileo Galilei almost two centuries later, Bonaiuti was buried in the Florence's Basilica of Santa Croce, the resting place of many significant historical figures, including the sculptor Michelangelo Buonarotti, the statesman and author Niccolò Machiavelli and the composer Gioachino Rossini.

Galileo's financial situation might have been better had he not deviated from his father's wish for him to study medicine, which at the time offered a better prospect of a comfortable career. But after his early experiments with pendulums while ostensibly studying medicine, he attended a lecture on geometry and persuaded his father to let him switch to mathematics and natural philosophy.  Soon, his inventive mid led to his creation of a thermoscope, a forerunner of the thermometer.

In time Galileo became Chair of Mathematics at Pisa University before moving to the University of Padua, where he taught geometry, mechanics and astronomy and made significant discoveries in both pure science and applied science, for example on the strength of materials and in his advancement of the telescope. He enjoyed the patronage of the Medici and Barberini families at times during his life.

Following his conviction for heresy and subsequent house arrest, from 1633 until his death at Arcetri in 1642, Galileo wrote one of his finest works, Two New Sciences, about the laws of motion and the principles of mechanics.

Pisa's famous leaning tower is unmissable
by visitors to the Campo dei Miracoli
Travel tip:

Pisa, the town of Galileo’s birth, is famous the world over for its leaning tower, one of the most popular tourist attractions in Italy . Already tilting when it was completed in 1372, the bell tower of the cathedral is in Piazza del Duomo, also known as Piazza dei Miracoli or Campo dei Miracoli in the centre of Pisa.  Pisa's other attractions include a wealth of well-preserved Romanesque buildings, Gothic churches and Renaissance piazzas. The city has a lively charm enhanced by its reputation as a centre of education. The University of Pisa, founded in 1343, now has elite status, rivalling Rome’s Sapienza University as the best in Italy, and a student population of around 50,000 makes for a vibrant cafe and bar scene. Not far from the city is the resort of Marina di Pisa, a seaside town located 12km (7 miles) from Pisa that began to develop in the early 17th century and grew rapidly after a railway line from Pisa opened in 1892. That growth saw the opening of restaurants and hotels and the construction of many beautiful Art Nouveau and neo-medieval villas. 

The Museo Galileo in Florence is housed in the 11th century Palazzo Castellani on Piazza dei Giudici
The Museo Galileo in Florence is housed in the 11th
century Palazzo Castellani on Piazza dei Giudici
Travel tip:

The Museo Galileo in Florence is in Piazza dei Giudici close to the Uffizi Gallery. It houses one of the biggest collections of scientific instruments in the world in Palazzo Castellani, an 11th century building. The first floor's nine rooms contain the Medici Collections, which include his two extant telescopes and the framed objective lens from the telescope with which he discovered the Galilean moons of Jupiter, plus his thermometers and a collection of terrestrial and celestial globes. The nine rooms on the second floor house instruments and experimental apparatus collected by the 18th-19th century Lorraine dynasty, which bear witness of the remarkable contribution of Tuscany and Italy to the progress of electricity, electromagnetism and chemistry.  The museum is open Mondays to Sundays from 9.30 to 18.00, closing at 13.00 on Tuesdays. 

More reading:

(Picture credits: Telescopes by Sailko; Leaning Tower by Softeis; via Wikimedia Commons)

(Painting locations: Galileo portrait (1636-40) by Justin Sustermans, National Maritime Museum, Greenwich, London; Galileo facing the Roman Inquisition (1857) by Cristiano Banti, private collection)