Alkalies In chimistry, a term applied to all bodies which possess the following properties: .

a caustic taste; .

volatilizable by heat; .

capability of combining with acids, and of destroying their acidity; .

solubility in water, even when combined with carbonic acid; .

capability of converting vegetable blues to green. The term was formerly confined to three substances: .

potash or vegetable fixed alkali, generally obtained from the ashes of wood; .

soda or mineral fixed alkali, which is found in the earth and procured from marine plants; and .

ammonia or volatile alkali, an animal product. Modern chimistry has discovered many new substances to which the term is now extended. The alkalies were formerly considered as elementary substances; but it is now ascertained that they are all compounds. The alkalies are used in the manufacture of glass and soap, in bleaching and in medicine.