Evangelista Torricelli
Encyclopedia
Evangelista Torricelli was an Italian
physicist
and mathematician
, best known for his invention of the barometer
.
, part of the Papal States
. He was left fatherless at an early age and educated under the care of his uncle, a Camaldolese
monk, who first entered young Torricelli into a Jesuit College in 1624 to study mathematics and philosophy until 1626, when he sent Torricelli to Rome
in 1627 to study science under the Benedictine
Benedetto Castelli
, professor of mathematics
at the Collegio della Sapienza in Pisa
.
In 1632, shortly after the publication of Galileo's Dialogues of the New Science, Torricelli wrote to Galileo of reading it "with the delight [...] of one who, having already practiced all of geometry most diligently [...] and having studied Ptolemy
and seen almost everything of Tycho Brahe
, Kepler
and Longomontanus
, finally, forced by the many congruences, came to adhere to Copernicus
, and was a Galileian in profession and sect". (The Vatican condemned Galileo in June 1633, and this was the only known occasion on which Torricelli openly declared himself to hold the Copernican view.)
Aside from several letters, little is known of Torricelli's activities in the years between 1632 and 1641, when Castelli sent Torricelli's monograph
of the path of projectiles to Galileo, then a prisoner in his villa at Arcetri
. Although Galileo promptly invited Torricelli to visit, he did not accept until just three months before Galileo's death. During his stay, however, he wrote out Galileo's Discourse of the Fifth day. After Galileo's death on January 8, 1642, Grand Duke Ferdinando II de' Medici asked him to succeed Galileo as the grand-ducal mathematician and professor of mathematics in the University of Pisa
. In this role he solved some of the great mathematical problems of the day, such as finding a cycloid
's area and center of gravity. He also designed and built a number of telescopes and simple microscopes; several large lenses, engraved with his name, are still preserved at Florence. In 1644, he famously wrote in a letter: "We live submerged at the bottom of an ocean of air."
Torricelli died in Florence a few days after having contracted typhoid fever
, and was buried in San Lorenzo. The asteroid
7437 Torricelli
was named in his honor. He left all his belongings to his adopted son Alexander.
, fourteen times more dense than water. In 1643 he created a tube approximately one meter long, sealed at the top, filled it with mercury, and set it vertically into a basin of mercury. The column of mercury fell to about 76 cm, leaving a Torricellian vacuum above. As we now know, the column's height fluctuated with changing atmospheric pressure
; this was the first barometer. This discovery perpetuated his fame, and the Torr
, a unit used in vacuum
measurements, has been named for him.
, regarding the speed of a fluid flowing out of an opening, which was later shown to be a particular case of Bernoulli's principle
.
:
Italy
Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...
physicist
Physics
Physics is a natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.Physics is one of the oldest academic...
and mathematician
Mathematics
Mathematics is the study of quantity, space, structure, and change. Mathematicians seek out patterns and formulate new conjectures. Mathematicians resolve the truth or falsity of conjectures by mathematical proofs, which are arguments sufficient to convince other mathematicians of their validity...
, best known for his invention of the barometer
Barometer
A barometer is a scientific instrument used in meteorology to measure atmospheric pressure. Pressure tendency can forecast short term changes in the weather...
.
Biography
Evangelista Torricelli was born in FaenzaFaenza
Faenza is an Italian city and comune, in the province of Ravenna, Emilia-Romagna, situated 50 km southeast of Bologna.Faenza is noted for its manufacture of majolica ware glazed earthenware pottery, known from the name of the town as "faience"....
, part of the Papal States
Papal States
The Papal State, State of the Church, or Pontifical States were among the major historical states of Italy from roughly the 6th century until the Italian peninsula was unified in 1861 by the Kingdom of Piedmont-Sardinia .The Papal States comprised territories under...
. He was left fatherless at an early age and educated under the care of his uncle, a Camaldolese
Camaldolese
The Camaldolese monks and nuns are part of the Benedictine family of monastic communities which follow the way of life outlined in the Rule of St. Benedict, written in the 6th century...
monk, who first entered young Torricelli into a Jesuit College in 1624 to study mathematics and philosophy until 1626, when he sent Torricelli to Rome
Rome
Rome is the capital of Italy and the country's largest and most populated city and comune, with over 2.7 million residents in . The city is located in the central-western portion of the Italian Peninsula, on the Tiber River within the Lazio region of Italy.Rome's history spans two and a half...
in 1627 to study science under the Benedictine
Benedictine
Benedictine refers to the spirituality and consecrated life in accordance with the Rule of St Benedict, written by Benedict of Nursia in the sixth century for the cenobitic communities he founded in central Italy. The most notable of these is Monte Cassino, the first monastery founded by Benedict...
Benedetto Castelli
Benedetto Castelli
Benedetto Castelli , born Antonio Castelli, was an Italian mathematician. He took the name "Benedetto" upon entering the Benedictine Order in 1595....
, professor of mathematics
Mathematics
Mathematics is the study of quantity, space, structure, and change. Mathematicians seek out patterns and formulate new conjectures. Mathematicians resolve the truth or falsity of conjectures by mathematical proofs, which are arguments sufficient to convince other mathematicians of their validity...
at the Collegio della Sapienza in Pisa
Pisa
Pisa is a city in Tuscany, Central Italy, on the right bank of the mouth of the River Arno on the Tyrrhenian Sea. It is the capital city of the Province of Pisa...
.
In 1632, shortly after the publication of Galileo's Dialogues of the New Science, Torricelli wrote to Galileo of reading it "with the delight [...] of one who, having already practiced all of geometry most diligently [...] and having studied Ptolemy
Ptolemy
Claudius Ptolemy , was a Roman citizen of Egypt who wrote in Greek. He was a mathematician, astronomer, geographer, astrologer, and poet of a single epigram in the Greek Anthology. He lived in Egypt under Roman rule, and is believed to have been born in the town of Ptolemais Hermiou in the...
and seen almost everything of Tycho Brahe
Tycho Brahe
Tycho Brahe , born Tyge Ottesen Brahe, was a Danish nobleman known for his accurate and comprehensive astronomical and planetary observations...
, Kepler
Johannes Kepler
Johannes Kepler was a German mathematician, astronomer and astrologer. A key figure in the 17th century scientific revolution, he is best known for his eponymous laws of planetary motion, codified by later astronomers, based on his works Astronomia nova, Harmonices Mundi, and Epitome of Copernican...
and Longomontanus
Christian Sørensen Longomontanus
Christen Sørensen Longomontanus was a Danish astronomer.The name Longomontanus was a Latinized form of the name of the village of Lomborg, Jutland, Denmark, where he was born. His father, a laborer called Søren, or Severin, died when he was eight years old...
, finally, forced by the many congruences, came to adhere to Copernicus
Nicolaus Copernicus
Nicolaus Copernicus was a Renaissance astronomer and the first person to formulate a comprehensive heliocentric cosmology which displaced the Earth from the center of the universe....
, and was a Galileian in profession and sect". (The Vatican condemned Galileo in June 1633, and this was the only known occasion on which Torricelli openly declared himself to hold the Copernican view.)
Monograph
A monograph is a work of writing upon a single subject, usually by a single author.It is often a scholarly essay or learned treatise, and may be released in the manner of a book or journal article. It is by definition a single document that forms a complete text in itself...
of the path of projectiles to Galileo, then a prisoner in his villa at Arcetri
Arcetri
Arcetri is a region of Florence, Italy, in the hills to the south of the city centre.-Landmarks:A number of historic buildings are situated there, including the house of the famous scientist Galileo Galilei ,...
. Although Galileo promptly invited Torricelli to visit, he did not accept until just three months before Galileo's death. During his stay, however, he wrote out Galileo's Discourse of the Fifth day. After Galileo's death on January 8, 1642, Grand Duke Ferdinando II de' Medici asked him to succeed Galileo as the grand-ducal mathematician and professor of mathematics in the University of Pisa
University of Pisa
The University of Pisa , located in Pisa, Tuscany, is one of the oldest universities in Italy. It was formally founded on September 3, 1343 by an edict of Pope Clement VI, although there had been lectures on law in Pisa since the 11th century...
. In this role he solved some of the great mathematical problems of the day, such as finding a cycloid
Cycloid
A cycloid is the curve traced by a point on the rim of a circular wheel as the wheel rolls along a straight line.It is an example of a roulette, a curve generated by a curve rolling on another curve....
's area and center of gravity. He also designed and built a number of telescopes and simple microscopes; several large lenses, engraved with his name, are still preserved at Florence. In 1644, he famously wrote in a letter: "We live submerged at the bottom of an ocean of air."
Torricelli died in Florence a few days after having contracted typhoid fever
Typhoid fever
Typhoid fever, also known as Typhoid, is a common worldwide bacterial disease, transmitted by the ingestion of food or water contaminated with the feces of an infected person, which contain the bacterium Salmonella enterica, serovar Typhi...
, and was buried in San Lorenzo. The asteroid
Asteroid
Asteroids are a class of small Solar System bodies in orbit around the Sun. They have also been called planetoids, especially the larger ones...
7437 Torricelli
7437 Torricelli
7437 Torricelli is a main-belt asteroid discovered on March 12, 1994 by Vittorio Goretti at Cima Ekar. It is named after the Italian physicist and mathematician Evangelista Torricelli, inventor of the barometer, and after whom the torr unit of pressure is named.- External links :*...
was named in his honor. He left all his belongings to his adopted son Alexander.
Barometer
Torricelli's chief invention was the mercury barometer, which arose from solving a practical problem. Pump makers of the Grand Duke of Tuscany attempted to raise water to a height of 12 meters or more, but found that 10 meters was the limit with a suction pump. Torricelli employed mercuryMercury (element)
Mercury is a chemical element with the symbol Hg and atomic number 80. It is also known as quicksilver or hydrargyrum...
, fourteen times more dense than water. In 1643 he created a tube approximately one meter long, sealed at the top, filled it with mercury, and set it vertically into a basin of mercury. The column of mercury fell to about 76 cm, leaving a Torricellian vacuum above. As we now know, the column's height fluctuated with changing atmospheric pressure
Atmospheric pressure
Atmospheric pressure is the force per unit area exerted into a surface by the weight of air above that surface in the atmosphere of Earth . In most circumstances atmospheric pressure is closely approximated by the hydrostatic pressure caused by the weight of air above the measurement point...
; this was the first barometer. This discovery perpetuated his fame, and the Torr
Torr
The torr is a non-SI unit of pressure with the ratio of 760 to 1 standard atmosphere, chosen to be roughly equal to the fluid pressure exerted by a millimetre of mercury, i.e., a pressure of 1 torr is approximately equal to 1 mmHg...
, a unit used in vacuum
Vacuum
In everyday usage, vacuum is a volume of space that is essentially empty of matter, such that its gaseous pressure is much less than atmospheric pressure. The word comes from the Latin term for "empty". A perfect vacuum would be one with no particles in it at all, which is impossible to achieve in...
measurements, has been named for him.
Torricelli's Law
Torricelli also discovered Torricelli's LawTorricelli's Law
Torricelli's law, also known as Torricelli's theorem, is a theorem in fluid dynamics relating the speed of fluid flowing out of an opening to the height of fluid above the opening....
, regarding the speed of a fluid flowing out of an opening, which was later shown to be a particular case of Bernoulli's principle
Bernoulli's principle
In fluid dynamics, Bernoulli's principle states that for an inviscid flow, an increase in the speed of the fluid occurs simultaneously with a decrease in pressure or a decrease in the fluid's potential energy...
.
Cause of wind
Torricelli gave the first scientific description of the cause of windWind
Wind is the flow of gases on a large scale. On Earth, wind consists of the bulk movement of air. In outer space, solar wind is the movement of gases or charged particles from the sun through space, while planetary wind is the outgassing of light chemical elements from a planet's atmosphere into space...
:
Italian submarines
Several Italian Navy submarines were named after Evangelista Torricelli- A Micca class submarine, built in 1918, stricken in 1930
- An Archimede class submarineArchimede class submarineThe Archimede class were a group of submarines built for the Italian Navy in the early 1930s. The boats fought in the Spanish Civil War and in World War II...
(1934), transferred to Spain in 1937 and renamed General Mola, stricken in 1959 - A Benedetto Brin class submarineBrin class submarineThe Brin-class submarines were five Italian submarines that served in the Regia Marina during World War II. All ships were built by Tosi. Two boats were replacements for Archimede-class submarines secretly transferred to the Nationalists during the Spanish Civil War in 1937. The class were...
(1937), sank in the Red Sea due to the British Navy in 1940 - Evangelista Torricelli , the former USS Lizardfish USS Lizardfish (SS-373)USS Lizardfish , a Balao-class submarine, was a ship of the United States Navy named for the lizardfish, a slender marine fish having a scaly lizardlike head and large mouth....
, transferred to Italy in 1960 and decommissioned in 1976
Selected works
His manuscripts are preserved at Florence, Italy. The following have appeared in print:- Trattato del moto (before 1641)
- Opera geometrica (1644)
- Lezioni accademiche (printed 1715)
- Esperienza dell'argento vivo (Berlin, 1897).
See also
- Parabola of safetyParabola of safetyIn classical mechanics and ballistics, the parabola of safety or safety parabola is the envelope of the parabolic trajectories of projectiles shot from a certain point with a given speed at different angles to horizon in a fixed vertical plane...
- Torricelli's EquationTorricelli's equationTorricelli's equation is an equation created by Evangelista Torricelli to find the final velocity of an object moving with a constant acceleration without having a known time interval.The equation itself is: v_f^2 = v_i^2 + 2 a \Delta d \,- Derivation :...
- Torricelli/Fermat pointFermat pointIn geometry the Fermat point of a triangle, also called Torricelli point, is a point such that the total distance from the three vertices of the triangle to the point is the minimum possible...
- Gabriel's hornGabriel's HornGabriel's Horn is a geometric figure which has infinite surface area but encloses a finite volume. The name refers to the tradition identifying the Archangel Gabriel as the angel who blows the horn to announce Judgment Day, associating the divine, or infinite, with the finite...