He names the place Cypsella or Chypsilar, and says that the alum in commerce is called alumen Lesbium, or di Metelin.
The alumen of the ancients, then, was not the same with the alum of the moderns.
Pliny informs us that alumenwas found naturally in the earth.
Several other species of alumenare described by Pliny, but we are unable to make out to what minerals he alludes.
What thealumen rotundum was, is not easily conjectured.
He says that, for medical purposes, the most valued of all the varieties of alumen were the slaty, the round, and the liquid.
Alumen nigrum was used to strike a black colour, and must therefore have contained iron.
When iron is dabbed over with alumen and vinegar it becomes like copper, according to Pliny.
I suspect strongly that the capillary crystals from the schistose alumen of Dioscorides were nearly of the same nature.
From Pliny’s account of the uses to which alumen was applied, it is quite obvious that it must have varied very much in its nature.
In its nature, it was similar to the alumen candidum; it must therefore have consisted chiefly, at least, of sulphate of alumina.
Dioscorides says, that it was sometimes made artificially; but that the artificial alumen rotundum was not much valued.
He also mentions that this dark alumen was used for purifying gold.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "alumen" in a variety of sentences. We hope that you will now be able to make sentences using this word.
