The precious metals and the sulphides of the base metals are rare.
The base metals oxydize and are absorbed with the lead into the pores of the cupel.
No difference in this respect between the base metals and the precious.
The gold which the alchemists tried to make from base metals.
Crossing these, at various angles, are veins containing the precious and base metals.
Large beds of limestone also exist in connection with the precious and base metals, which are next to be described.
And from this we can calculate whether it will be worth while to separate the precious metals from the base metals, or not.
Gold and silver are now reckoned as precious metals and all the others as base metals.
If the base metals are not gold, it is only through some accidental hindrance; they are-all potentially gold.
The ripened product was gold, while the green fruit, in various stages of maturity, was represented by the base metals.