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Similarly, when the moisture corrodes friable cupriferous pyrites an acrid juice is made from which is produced vitriol and sometimes alum; or, finally, juices are pressed out by the very force of the heat from the earth.

Since I have explained the nature of vitriol and its relatives, which are obtained from cupriferous pyrites, I will next speak of an acrid solidified juice which commonly comes from cadmia.

The description is no doubt that of the Mannsfeld cupriferous slates.

This is black, bituminous, and cupriferous, and when first extracted from the mine it is thrown out into an open space and heaped up in a mound.

If the ore contains any stibium, then iron slag is added to it; if pyrites, then are added cakes melted from a cupriferous stone and sand made from stones which easily melt.