Note 10 — BOOK VII.
Herbert Hoover translation
The reader is referred to note 6, p. 558, for more ample discussion of the alkalis. Agricola gives in this chapter four substances of that character:
Soda (nitrum). Lye. "Ashes which wool-dyers use." "Salt made from the ashes of musk ivy."
The last three are certainly potash, probably impure. While the first might be either potash or soda, the fact that the last three are mentioned separately, together with other evidence, convinces us that by the first is intended the nitrum so generally imported into Europe from Egypt during the Middle Ages. This imported salt was certainly the natural bicarbonate, and we have, therefore, used the term "soda."