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C - 5 : What did Galileo Galilei do in Venice?

We all know the story of the Italian physicist, mathematician and engineer Galileo Galilei who was draged before the Catholic Inquisition in 1633 because he did not recant his belief that the Earth circled around the Sun. Leaving the court after being sentenced to prison for life he apparantly uttered the words “e pur si muove” (and yet it moves).

Galileo portrait by Domenice Tintoretto A bit less known is what a practical scientist and engineer Galileo was. Born in Pisa in 1564, he studied medicine at the Pisa University in 1580 but switched to mathematics a year later. By 1589 when he was appointed Head of the Mathematics Unit at his university, he had already invented the thermoscope, an innovation he used as base for building the first thermometer a decade later. In 1592 he moved to the University of Padua which brought him into Venice’s realm.

Galileo demonstrating his version of the Telescope to the Doge in 1609

During his tenure at Padua, Galileo tought geometry, mathematics and mechanics. He was keenly interested in Aristotele’s writing and developed many of his principles further. Of particular interest to Galileo were the laws of motion and material strength - somethng that had a very practical application to ballistic and ship building. His talents did not stay unnoticed. By 1593, not even 30 years old, the Venetian Arsenal hired him as a consultant.

View of the Arsenal South Entrance in 1732 - it still looks very much the same - we dock nearby on the 16 August when arriving in Venice

In this role, Galileo advised the navel engineers on a variety of subjects. He helped ship-builders strengthening hulls by making them more flexible, improved compass designs for military and commercial use, helped gun makers to calculate the balistics and to optimise gunpowder charges (there were five to seven guns per galley), invented the thermometer and used it for weather forecasts and solved the vexing problem of oar arrangements to improve propulsion of the galleys. Galileo became famous for his invention of the refractional telescope - having heard about the invention in Holland the year before. His new design improved the magnifying factor to 8 or 9 times and was built in a sturdy manner. The Venetian Doge loved it. Soon, the entire Venetian fleet was equipped with the instrument - spotting the enemy early gave a nice battlefield advantage. The grateful Venetian Senate granted him a lifelong stipend of 1’000 Florins p.a.

Venetian Arsenal today from the air

The Venetian Arsenal, founded in 1104, was in Galileo’s time an industrial manufacturing site mankind had not seen before - it would take the industrial revolution to adopt the Arsenal’s principles of mass production. The division of labour was highly advanced - the Arsenal employed a specialised workforce of > 16’000 men. It is fair to say that half of Venice’s male population worked on Galleys for 4 months a year whilst the other half worked in and around the Arsenal (Venice had about 110’000 inhabitants).

Arsenale Nuovo (built 1320 as easter extension) with its dry docks and fitting halls

The main divisions of the Arsenal were shipbuilding (hulls from pre-fabricated frames), oar production, rope making, rigging, gun casting and gun powder manufacturing. Galleys were assembled from pre-made parts. Apparently the Arsenal could assemble a Galley within one day, moving the ship on the water from assembly point to assembly point. Somewhere I read - can’t remember where - that the Arsenal produced an entire new fleet of 50 Galleys within two months. It is no wonder that the Arsenal would be interested in a talented man like Galileo Galilei. He served as consultant until 1610 when his Venetian pension allowed him to retire and become an independent scientist.

Galileo’s manuscript where he describes his discovery of the moons of Jupiter

Once freed from official duties, it did not take Galileo long to direct his telescope (now magnifying by factor 30) to the sky. He discovered the craters on the moon, saw that Venus had the same phases as our lunar companion and found four of Jupiter’s moons - something you can do lying on the deck of our boat with the captain’s binoculars. All these findings confirmed his views of the heliocentric nature of our solar system - something that led to the infamous sentence and famous uttering in 1633. I sometimes wonder whether Galileo ever had built a telescope had he not worked for the Arsenal in Venice.

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