Note 1191 — KERMES. COCHINEAL.
William Johnston translation
Some have considered sandix as a mineral. Minerals however can be used for painting but not for dyeing. It may be replied that the Romans themselves dyed with kermes at this period, and that they must have easily procured it. But they understood the art of dyeing with it so badly that they employed it only for giving the ground of their purple, and on that account it must have appeared improbable to them that the people in India could produce by it a more beautiful colour than their purple was. From the like ignorance in modern times, indigo was decried, because people imagined that a complete colour could not be communicated by it; and this false conclusion retarded many improvements in the art of dyeing. It is very likely that the Greeks and the Romans were unacquainted with the effect produced upon kermes by acids, which the Persians and Indians used.