AL'KALI, noun plural 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.