Discovery of chlorine

Chlorine was first produced in 1774 by the Swedish chemist Carl Wilhelm Scheele, who heated hydrochloric acid with the mineral pyrolusite, which is manganese dioxide, and noticed a pungent greenish-yellow gas. Scheele believed it to be a compound containing oxygen, and this view was accepted for decades. In 1810 the English chemist Humphry Davy demonstrated that the gas was an element and named it chlorine, from the Greek chloros, meaning pale green. Chlorine bleaches textiles, and from the nineteenth century it was widely used to disinfect water, which greatly reduced diseases such as cholera and typhoid. It was also used as a chemical weapon, first on a large scale by Germany at Ypres in 1915. Today it is essential to the manufacture of plastics and many other products.

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