And in regard, Pyrophilus, that in the former Experiments, both the Infusion of Galls, and the Decoction of Roses, and the Solution of Copperis employ'd about them, are endow'd each of them with its own Colour, there may be a more noble Experiment of the sudden production of Blackness made by the way mention'd in the Second Section of the Second Part of our Essays, for though upon the Confusion of the two Liquors there mention'd, there do immediately emerge a very Black mixture, yet both the Infusion of orpiment and the Solution of Minium were before their being joyn'd together, Limpid and Colourless.
"Experiments and Considerations Touching Colours (1664)"
Robert Boyle
And this Experiment may, for ought I know, sometimes succeed; for I remember, that having in a small Bolt-head purposely sublim'd some powder'd orpiment, we could in the Lower part of the Sublimate discern here and there some Reddish Lines, though much of the Upper part of the Sublimate consisted of a matter, which was not alone purely Yellow, but transparent almost like a Powder.
"Experiments and Considerations Touching Colours (1664)"
Robert Boyle
It occurs as metallic arsenic, which is of a steel-grey colour, brittle, and gives off a garlic-like odour when heated; as arsenious acid; in the form of two sulphides-the red sulphide, or realgar, and the yellow sulphide, or orpiment; and as arsenite of copper, or Scheele's green.
"Aids to Forensic Medicine and Toxicology"
W. G. Aitchison Robertson