Al’ka-lĭ or Al’ka-lī, n.

(Synop., § 130), n.; pl. ALKA-LIES (-lĭz or -līz.) [Fr., Pr., & Sp. alcali, from Ar. al-qali, the ashes of the plant called glass-wort, from its use in the manufacture of glass, soda, from galaj, to roast in a pan, fry.] (Chem.) One of a class of caustic bases, soda, potash, ammonia, and lithia, whose distinguishing peculiarities are solubility in alcohol and water, uniting with oils and fats to form soap, neutralizing and forming salts with acids, reddening several vegetable yellows, and changing reddened litmus to blue. New Am. Cyc.

Fixed alkalies, potash and soda. — Vegetable alkalies. Same as ALKALOIDS, q. v. — Volatile alkali, ammonia, so called in distinction from the fixed alkalies.