The Roman History · Amm. 23.6.38

It is made in this manner. Those skilful in such arts mix common oil with a certain herb, keep it a long time and when the mixture is completed they thicken it with a material derived from some natural source, like a thicker oil. The material being a liquor produced in Persia, and called, as I have already said, naphtha in their native language.

Ammianus Marcellinus · translated by C. D. Yonge · 1911 reprint
C. D. Yonge translation (preface dated February 1862); G. Bell and Sons, 1911; Project Gutenberg #28587
Passage preview. Read in context for the complete text, notes and references.