The calcined matter is raked out, and lixiviated with water.
The whole is then lixiviated and decomposed by carbonate of potash.
When most of the copper has been converted into the sulphate, the ore is lixiviated.
If prepared by ignition, the semifused mass is lixiviated with water, and then evaporated to dryness.
It is raked out, and when cooled, lixiviated in great iron cisterns with false bottoms, covered with mats.
These ashes are collected, mixed with lime, lixiviated, and the resulting lye boiled down.
This earth is lixiviated with wood-ashes, which allows the nitre to take a crystalline form.
If the earths, after having been lixiviated, are replaced in the caves, they again become impregnated with the same salts.