a term frequently met with in the writings of physicians, chemists, &c. for certain medicines or menstrua, in a liquid form, distinguished from each other by peculiar epithets.

Aqua Extincta, or Extinguished Water, is aqua fortis into which some river water has been poured, in order to qualify it, and render it less corrosive.

Aqua Fortis, a name given by artists to nitric acid of a certain strength, from its dissolving power.

Aqua Marina, a name by which the jewellers call the beryl, on account of its sea-green colour.

Aqua Regia, a compound of nitric and muriatic acid, in different proportions, according to the purpose for which it is intended. It is usually made by dissolving in nitric acid either sal ammoniac or common salt, both of which are combinations of muriatic acid with alkali.

Aqua Secunda, aqua fortis diluted with much pure water. It is employed in several arts to clear the surface of metals and certain stones.