Approximately 400 years ago, around 1625, the Flemish chemist Jan Baptist van Helmont (1579–1644) introduced the term "gas" into scientific discourse. He derived the term from the Greek word chaos (χάος), reflecting his conception of an unformed, chaotic state of matter. Van Helmont used "gas" to describe substances that were neither solid nor liquid, with a particular focus on what we now recognize as gases. His pioneering work greatly advanced early chemistry and the study of gases, particularly through his experiments on carbon dioxide, which he referred to as “gas sylvestre”.
Van Helmont's ideas about substances, their properties, and their chemical reactions were instrumental in the transition from alchemy to modern chemistry. His emphasis on experimentation and his conceptualization of gas laid important foundations for scientific thought in the 17th and 18th centuries.
This historical milestone connects the chemistry of the 17th century to contemporary issues, including climate change and environmental challenges. We are particularly interested in papers that examine the philosophical dimensions of Van Helmont’s experiments and ideas, as well as their influence on later scientists such as Robert Boyle (1627–1691), Franciscus Sylvius (1614–1672), Johann Joachim Becher (1635–1682), Georg Ernst Stahl (1660–1734) and Antoine Lavoisier (1743–1794). Additionally, we welcome discussions on the broader historical significance of gases.