Gas state

Before the 17th century, the Greek four-element model dictated that any vapor was just generic "air." van Helmont overturned this by demonstrating that distinct types of "airs" exist, just like distinct solids and liquids, and coined the term "gas."
 Jan Baptista von Helmont Flanders 1624 Gas state

Before the 17th century, the Greek four-element model dictated that any vapor was just generic "air." van Helmont overturned this by demonstrating that distinct types of "airs" exist, just like distinct solids and liquids, and coined the term "gas."