It's impossible to say who "invented" gas, as it's a natural substance that has existed since the beginning of the universe. However, we can talk about the people who discovered and understood the properties of different gases:

* Ancient Greeks: Philosophers like Democritus and Leucippus theorized about the existence of tiny particles called "atoms" which made up everything, including gases.

* Jan Baptista van Helmont (1579-1644): This Flemish chemist coined the term "gas" from the Greek word "chaos" to describe a substance that could escape from containers. He conducted experiments with gases like carbon dioxide.

* Robert Boyle (1627-1691): This Irish physicist and chemist is credited with developing Boyle's Law, which describes the relationship between the pressure and volume of a gas.

* Henry Cavendish (1731-1810): This British scientist isolated hydrogen and studied its properties.

* Joseph Priestley (1733-1804): He isolated and studied oxygen, and he is considered the discoverer of this crucial gas.

* Antoine Lavoisier (1743-1794): This French chemist revolutionized the understanding of gases with his work on combustion and the law of conservation of mass.

The understanding of gases progressed over centuries with contributions from many scientists. Each scientist built upon the work of others to uncover the mysteries of these invisible substances.