Are there not different sorts of this material?
The principal kinds are native alums: viz. those prepared and perfected underground by the spontaneous operations of nature; as the roch, commonly called rock alum, from Rocha, in Syria, whence it is brought.
Spontaneous, unassisted by art.
Orientals, inhabitants of the Eastern parts of the world.
What is Ink?
A liquor used in writing on paper or parchment, made of copperas, galls; and gum arabic[6] mixed together. There are likewise several plants that may serve for the making of ink, as oak-bark, red roses, log-wood, &c. It is also made from an infusion of oak galls and iron filings: there are also many other ways, as well as materials, employed in the making of this useful article. Ink is the name applied to all liquids used in writing, of whatever color they may be, as red, blue, &c., though black is the most used for common purposes. The ink of the ancients seems to have been of a thick, oily nature, unlike the modern ink; it consisted of nothing more than a species of soot, or ivory black, mixed with one fourth of gum.
[6] See [Chapter XI].
What is Copperas?
A kind of vitriol. Copperas is the name given to green vitriol, which is a preparation from iron. The blue vitriol is a sulphate of copper, and the white vitriol a sulphate of zinc.
For what is Vitriol used?