Besides the working in metals there were some other branches of industry practised by the ancients, so intimately connected with chemical science, that it would be improper to pass them over in silence. The most important of these are the following:
It is well known that the ancient Grecian artists carried the art of painting to the highest degree of perfection, and that their paintings were admired and sought after by the most eminent and accomplished men of antiquity; and Pliny gives us a catalogue of a great number of first-rate pictures, and a historical account of a vast many celebrated painters of antiquity. In his own time, he says, the art of painting had lost its importance, statues and tablets having came in place of pictures.
Two kinds of colours were employed by the ancients; namely, the florid and the austere. The florid colours, as enumerated by Pliny, were _minium_, _armenium_, _cinnaberis_, _chrysocolla_, _purpurissum_, and _indicum purpurissum_.
The word _minium_ as used by Pliny means _red lead_; though Dioscorides employs it for bisulphuret of mercury or cinnabar.
_Armenium_ was obviously an ochre, probably of a yellow or orange colour.
_Cinnaberis_ was bisulphuret of mercury, which is known to have a scarlet colour. Dioscorides employs it to denote a vegetable red colour, probably similar to the resin at present called _dragon’s blood_.
_Chrysocolla_ was a green-coloured paint, and from Pliny’s description of it, could have been nothing else than carbonate of copper or malachite.
_Purpurissum_ was a _lake_, as is obvious from the account of its formation given by Pliny. The colouring matter is not specified, but from the term used there can be little doubt that it was the liquor from the shellfish that yielded the celebrated purple dye of the Tyrians.
_Indicum purpurissum_ was probably _indigo_. This might be implied from the account of it given by Pliny.
The austere colours used by the ancient painters were of two kinds, native and artificial. The native were _sinopis_, _rubrica_, _parætonium_, _melinum_, _eretria_, _auripigmentum_. The artificial were, _ochra_, _cerussa usta_, _sandaracha_, _sandyx_, _syricum_, _atramentum_.
_Sinopis_ is the red substance now known by the name of reddle, and used for marking. On that account it is sometimes called _red chalk_. It was found in Pontus, in the Balearian islands, and in Egypt. The price was three denarii, or 1_s._ 11¼_d._ the pound weight. The most famous variety of _sinopis_ was from the isle of Lemnos; it was sold sealed and stamped: hence it was called _sphragis_. It was employed to adulterate minium. In medicine it was used to appease inflammation, and as an antidote to poison.