The History of Chlorine

One of these natural compounds, sodium chloride, has been known since ancient times. Societies, through the use of rock salts and brine, used sodium chloride as early as 6,000 BCE. Chemists, starting in the later stages of the Renaissance, explored these chloride compounds; Jan Baptist van Helmont identified chlorine as a gas in 1630. Carl Wilhelm Scheele isolated elemental chlorine in 1774, but didn’t grasp the totality of his discovery; chlorine itself was identified and named by Sir Humphry Davy in 1810, using the Greek word chloros, meaning “green-yellow”. By the early 1820s the properties of elemental chlorine were clear; this substance was widely used as a disinfectant and by 1918 the United States Department of Treasury called for all drinking water to be treated with chlorine.