A revolution can be defined as a relatively sudden and completely drastic change. The chemical revolution took place in the eighteenth century, it started when the notion of a gaseous state that elements could exist in was proposed, and finished when Lavoisier published his textbook,Traité élémentaire de Chimie. Despite the fact that many important discoveries took place prior to the eighteenth century, these were not large enough to completely change chemistry and isolate it from its ancient roots as eighteenth century chemistry did. The discoveries that took place in the eighteenth century revolutionised chemistry, and did this by disproving ancient fundamentals and developing more logical theories to replace them.