Note 17 — BOOK VII.
Herbert Hoover translation
Recrementum vitri. (Interpretatio, Glassgallen). Formerly, when more impure materials were employed than nowadays, the surface of the mass in the first melting of glass materials was covered with salts, mostly potassium and sodium sulphates and chlorides which escaped perfect vitrification. This "slag" or "glassgallen" of Agricola was also termed sandiver.