AL'KALI, n. plu. Alkalies In chimistry, a term applied to all bodies which possess the following properties:1. a caustic taste;2. volatilizable by heat;3. capability of combining with acids, and of destroying their acidity;4. solubility in water, even when combined with carbonic acid;5. capability of converting vegetable blues to green.The term was formerly confined to three substances:1. potash or vegetable fixed alkali, generally obtained from the ashes of wood;2. soda or mineral fixed alkali, which is found in the earth and procured from marine plants; and 3. 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.
|