Jan van Helmont. Engraving of Jan (or Johannes) Baptista van Helmont (1579-1644), Belgian chemist and alchemist. Van Helmont's work represents a transition from traditional alchemy to experimental chemistry. He was the first person to use the word gas", deriving it from the Greek word "chaos". He also realised that matter was indestructable and that metals dissolved in acid could be recovered. He believed that all matter was made of a combination of air and water. He also claimed that religious artifacts created miracles through magnetic effects. This belief created religious opposition to his work, meaning that it was not published until after his death."