Vitriolic Collyrium.
Take of white vitriol, half a drachm: rose-water, six ounces. Dissolve the vitriol in the water, and filter the liquor.
This, though simple, is perhaps equal in virtue to most of the celebrated collyria. It is an useful application in weak, watery, and inflamed eyes. Though the slighter inflammations will generally yield to it, yet in those of a more obstinate nature the assistance of bleeding and blistering will often be necessary,
When a strong astringent is judged proper, a double or triple quantity of the vitriol may be used. I have seen a solution of four times the strength of the above used with manifest advantage.
William Buchan
Domestic Medicine 2nd edition 1785