Giovanni Battista Baliani

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Giovanni Battista Baliani (* 1582 in Genoa ; † 1666 ibid) was an Italian mathematician and physicist. He was Galileo Galilei's correspondent .

Life

Baliani came from a wealthy patrician family in Genoa (his father was a senator), studied law and then worked for the Republic of Genoa. He was prefect of the fortress of Savona in 1611 . In 1623 he became governor of Sarzana and in 1624 a member of the Genoese Senate. From 1647 to 1649 he was governor of Savona. He was then on the Genoa Council until his death. He was also a captain in the Genoese archers .

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He corresponded with Galileo for many years, beginning in 1614. Filippo Salviati drew Galileo's attention to him after meeting Baliani in 1613. At first they corresponded about the weight of the air. He met Galileo and Benedetto Castelli in Florence in 1615.

In Savona, he repeated Galileo's fall experiment on free fall at the fortress : he dropped cannonballs from their walls and noticed that the time of fall was independent of weight.

He also managed to bring a pot of water to a boil by friction by rotating it at high speed. The early experiment showed the equivalence of mechanical work and heat.

His main work is De motu naturali gravium, fluidorum et solidorum from 1638 (reissued with many additions in 1646). It was published before the Discorsi of Galileo in the same year, but its independence has been questioned because of its correspondence with Galileo. It contained the correct mathematical description of accelerated movement (as of course also with Galileo) and the distinction between inert and heavy mass (weight) as agens (active) and passum (passive). He also dealt with movement on the inclined plane and equal oscillation periods independent of the deflection during pendulums. However, he was still attached to traditional Aristotelian physics. For example, he rejected the trajectory parabola.

In 1641 he developed a water barometer. In a letter to Galileo in 1630, he asked him why he could not raise water to 21 m with ordinary pumps (he suspected that the air pressure was the cause of the operation of this pump, in contrast to Galileo) - Galileo already gave the correct answer that with Such methods can basically only be sucked in to around 11 m of water. This inspired Galileo and, through him, Torricelli and later other famous scientists ( Blaise Pascal , Robert Boyle and others) to deal with these questions. Baliani also corresponded with Marin Mersenne (Pascal belonged to his circle in Paris).

In 1647 he published a treatise on the plague, which he attributed to chemical causes. There he also gives quantitative arguments for the limitation of population growth through war and disease on the one hand and food production on the other hand and his arguments show him as a forerunner of Malthus .

He supported Galileo's theory of tides, which was attributed to the motion of the earth and moon. Giovanni Battista Riccioli published his views on this in 1651 in his Almagestum novum. This was recorded by John Wallis and Isaac Newton . In general, Baliani was more of a supporter of Tycho Brahe than of Nicolaus Copernicus .

He also dealt with shipbuilding considerations in the posthumous writings published in 1666. It also contains considerations about movement in a vacuum, optical experiments with prisms, and discussion of light and long-range effects. He also dealt with elastic collisions.

He conducted extensive correspondence not only with Galileo but also with other scientists such as Marin Mersenne.

De motu naturali gravium solidorum et liquidorum

Fonts

  • De motu naturali gravium solidorum, Genoa 1638
  • De motu naturali gravium solidorum et liquidorum, Genoa 1646
    • Giovanna Baroncelli (ed.), De motu naturali gravium solidorum et liquidorum , Giunti, Florence 1998
  • Trattato della pestilenza , Savona 1647
  • Opere diverse, Genoa 1666 - Dialoghi , Dell'amicitia , Delle onde del mare , Trattatello della lettera di cambio , Opuscula
  • Opere diverse di Gio. Battista Baliani, patrizio genovese; aggiuntovi nell'avviso a chi legge, una compendiosa notiza di lui vita , Genoa 1792
  • The correspondence with Galileo is in his edition.

literature

Web links

Individual evidence

  1. ↑ Nothing specific is known about the course. It is possible that he also studied at the Jesuit college in Genoa.
  2. ↑ The tradition of such experiments existed even then independently of Galileo, based on Giovanni Battista Benedetti . For example, Simon Stevin carried out such experiments in the Netherlands in 1586 - indirectly influenced by a plagiarism of the work of Benedetti. Other scientists in Italy also looked at it, e.g. B. Giuseppe Moletti (1576), forerunner of Galileo in Padua, and Jacopo Mazzoni .
  3. ↑ In the second edition, however, there is a discussion in which there is speculation about the cause of the acceleration through microscopic (incremental) impacts (constant impulse increases over time, which accumulate in this way, in the manner of impetus theory ) and which has been wrongly interpreted as such is as if he had disregarded the correct law of acceleration (Stillman Drake in Dictionary of Scientific Biography).
  4. ^ Reprinted in 1792 with a biography
  5. ↑ See also: Baliani Giovanni Battista a Galilei Galileo. Museo Galileo, accessed February 20, 2018 (Italian).
personal data
SURNAME Baliani, Giovanni Battista
BRIEF DESCRIPTION Italian mathematician and physicist
DATE OF BIRTH 1582
PLACE OF BIRTH Genoa
DATE OF DEATH 1666
Place of death Genoa