A soda fountain is a machine that produces carbonated soft drinks, known as fountain drinks. It does this by mixing a flavored syrup or a concentrate, with carbon dioxide and purified (usually chilled) water. The process can either be done manually, or it can be automated, by a vending machine. The first soda fountains appeared in the 18th century. They spread during the 19th century and were widely used by the early 20th century.