Benedetti, GB
Name: Giovanni Battista Benedetti
Achievements: Contributions to the advance of mathematics, mechanics and music theory
Born: August 14 1530; Venice, Italy
Died: January 20, 1590; Turin, Italy (Aged 60)
Field & Discipline: Science; Physics; Mathematics; Mathematician; Physicist
Language: Italian
Father: Unknown
Mother: Unknown
Siblings: Unknown
Spouse: Unknown
Children: 1 daughter
Education: Taught at home by his father
Major Work:
"Speculationum" (1585)
Life & Times:
As a teenager, Benedetti studied geometry under the mathematician [taught by] Tartaglia* who introduced him to [studied work of] Euclid’s* work. In his first book, "Resolutio" (1553), Benedetti gave solutions to all the problems in Euclid's "Elements." As a preface to his book, Benedetti included a letter of dedication (to Gabriel de Guzman, a learned Spanish priest with whom Benedetti had discussed mathematics) about Benedetti's theory of the free fall of bodies.
It was his first significant contribution to the introduction of modern physics. He stated that bodies of the same density, whatever their weight, would fall through a given medium at the same speed. His argument was based on the application of the principle of Archimedes to free fall, and it opposed [opposed arguments of] Aristotle’s* physics (the accepted wisdom at then time) which stated that bodies would fall at a speed proportional to their weight. [influenced] Galileo* repeated Benedetti almost exactly forty years later.
Aristotle's view had been accepted for centuries and "Resolutio" caused a stir throughout Italy with some people refusing to accept his conclusions. Benedetti's response was to write another book, "Demonstratio" (1554) in which he quoted passages from Aristotle to make it quite clear that he was indeed contradicting him.
In the second edition of "Demonstratio" Benedetti also corrected his own original theory by stating that the resistance of the medium through which the bodies are falling is proportional to the surface, not the volume, of the falling body, implying that only in a vacuum would bodies of the same density but of differing weights fall at an absolutely equal speed. (Dave Scott, Commander of Apollo 15 would prove him right over four hundred years later on the surface of the Moon, although as he did so he mistakenly referred not to Benedetti but Galileo).
In 1558 Benedetti left Venice to become court mathematician to Duke Ottavio Farnese in Parma. He taught mathematics, acted as a consultant engineer and court astrologer, and built elaborate sundials. He was also interested in music and became friendly with the court choir master, Cipriano da Rore. When Rore returned to Venice, Benedetti corresponded with him and in two letters dated 1563 made a pioneering contribution to music theory.
Benedetti disregarded the current numerical theories of harmony and conducted his own investigation into the relation of pitch, consonance, and rates of vibration. He concluded that the production of musical consonances was related to the behaviour of waves of air caused by the vibration of strings: the waves either agreed, with or broke in upon one another. From this principle, Benedetti drew up a mathematical scale of concordance.
In 1567 he moved to Turin where he joined the court of the Duke of Savoy as adviser in
mathematics and science at court.
He also served as engineering consultant and advised on the improvement of military installations. He built fountains and sundials and in 1573 published a treatise on sundials. The duke loved to hear scholars arguing about science and philosophy and Benedetti's next work, "Consideratione" (1579), came as the result of a debate on the relative volumes of earth and water.
His major work was Speculationum" (1585) a collection of papers on mathematical and scientific topics, the most valuable Italian contribution to physics before Galileo. It included geometrical solutions to numerical problems and a treatise on perspective; in the section on mechanics Benedetti gave a description of hydrostatic pressure and the concept of a hydraulic lift; he also made observations on the climate, offering theories about wind, clouds and the heat of the sun.
Benedetti's methodology included precise observation and accurate tables. His astronomical observations were made in the service of astrology rather than astrophysics but he did state, correctly, that the red colour of a totally eclipsed moon is caused by the refraction of sunlight in the earth's atmosphere.
Benedetti forecast his own death for 1592 but in 1590 he realised he was dying and recast his horoscope, declaring that the original data had been four minutes out.
Extra Connections: His work affected that of [influenced] Stevin*
He was influenced by the earlier work of [influenced by] Witelo*
Assessment: Benedetti was Galileo's most important predecessor in Italy.
Oneliner: GB Benedetti, who anticipated Galileo’s free-fall work
Bibliography:
- Dictionary of Scientific Biography.
- Drake, Stillman & Drabkin, IE, Mechanics in Sixteenth-Century Italy, University of Wisconsin Press, Madison, Milwaukee & London, 1969.