Note 283 — Chapter III · (continued 2)
Walter Armstrong translation
M. Soldi remarks, in connection with the Mexicans, that they managed to cut the hardest rocks and to engrave finely upon the emerald with nothing but bronze tools. Prescott and Humboldt bear witness to the same fact. The Peruvians also succeeded in piercing emeralds without iron. Their instrument is said to have been the pointed leaf of a wild plantain, used with fine sand and water. With such a tool the one condition of success was time (Les Arts Méconnus, pp. 352-359).