Aqua valens

Book Ten deals with the making of the mineral acids used in assaying and in parting operations. Aqua valens is the term which Agricola employs indiscriminately for the acids or mixtures of acids, ignoring the terms aqua fortis or aqua regia then already introduced by previous writers. His description of the materials used for preparation would indicate that a considerable variety of strength and composition of these acids were in use. He describes ten recipes for the materials to be subjected to distillation in the furnace. 

NITRIC ACID. [CAS 7697-37-2]. This important industrial chemical has been known for at least 1000 years. The acid was known to alchemists as aquafortis (strong water) or aqua valens (powerful water). Nitric acid... 

FIGURE 21. Distillation of aqua valens ( powerful water ), a general term used by Agricola to describe powerful acids such as aqua fortis (nitric acid) and aqua regia (hydrochloric acid/nitric acid, 3 1), depicted in the 1912 Hoover translation of Agricola s 1556 De Re Metallica. 

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