Chlorine was discovered in 1774 by Swedish chemist Carl Wilhelm Scheele, who called it "dephlogisticated marine acid" (see phlogiston theory) and mistakenly thought it contained oxygen. Davy showed that the acid of Scheeles substance, called at the time oxymuriatic acid, contained no oxygen. This discovery overturned Lavoisiers definition of acids as compounds of oxygen. In 1810, chlorine was given its current name by Humphry Davy, who insisted that chlorine was in fact an element. The name chlorine, chosen by Davy for "one of [the substance's] obvious and characteristic properties – its colour", comes from the Greek χλωρος (chlōros), meaning green-yellow.