Editorial note — INDEX
Reading edition
Glebas nitri. This is doubtless the natron (impure carbonate of soda) exported from the Egyptian natron lakes, which have been worked from a very early period—a substance that must not be confused with our nitre (nitrate of potash); as I have said, the glass of the ancients is essentially a soda glass. The natron was probably first exported for the use of the soap-makers.