Can vacuum exist?
Scientist were involved in an argument of whether vacuum could exist. Many scientists held on to the Aristotelian theory that vacuum was impossible. (Why did Aristotle believed this way?)
In 1613, Galileo Galilei (1564 – 1642) proposed and subsequently proved that air had both weight and density. As a result, for the first time, air was considered a substance with a specific weight. This brought about the further assumption that air could in some way, be removed from a given space
The vacuum pump was one of the six instruments invented in the 17th century that had a profound impact on experimental science, the others were the pendulum clock, the telescope, the thermometer, the barometer and the microscope
https://cds.cern.ch/record/455984/files/p281.pdf
Evangelista Torricelli, a physicist and mathematician was born in Italy. In 1641, Evangelista Torricelli moved to Florence to assist the astronomer Galileo. It was Galileo that suggested Evangelista Torricelli use mercury in his vacuum experiments. Evangelista Torricelli became the first scientist to create a sustained vacuum