1
Log-wood and cider, in iron, set with copperas, makes a good black.
2
If copperas be used instead of alum, slate color will be produced.
3
They next tried alum and copperas; but the great secret still escaped them.
4
Alum and copperas have been known in the Highlands long ages.
5
Of such vats the copperas and lime and the hydrosulphite vats are examples.
1
They were found to be made of green vitriol, starch and sugar.
2
Copperas is the name given to green vitriol, which is a preparation from iron.
3
Iron sulphate, or ferrous sulphate, is the green vitriol.
4
Ordinary writing ink was formerly always made from a decoction of galls, to which green vitriol was added.
5
For long, green vitriol was confused with blue vitriol, which generally occurs as an impurity in crude green vitriol.