The proper way of testing indicum is by laying it on hot coals, that which is genuine producing a fine purple flame, and emitting a smell like that of sea-water while it smokes: hence it is that some are of opinion that it is gathered from the rocks on the sea-shore. The price of indicum is twenty denarii per pound. Used medicinally, it alleviates cold shiverings and defluxions, and acts as a desiccative upon sores. CHAP. 28.—ARMENIUM; ONE REMEDY. Armenia sends us the colouring substance which is known to us by its name.[1922] This also is a mineral, which admits of being dyed, like chrysocolla,[1923] and is best when it most closely resembles that substance, the colour being pretty much that of cæruleum. In former times it was sold at thirty sesterces per pound; but there has been found of late in the Spanish provinces a sand which admits of a similar preparation, and consequently armenium has come to be sold so low as at six denarii per pound. It differs from cæruleum in a certain degree of whiteness, which causes the colour it yields to be thinner in comparison. The only use made of it in medicine is for the purpose of giving nourishment to the hair, that of the eyelids in particular. CHAP. 29.—APPIANUM. There are also two colours of very inferior quality, which have been recently discovered. One of these is the green known as “appianum,”[1924] a fair imitation of chrysocolla; just as though, we had not had to mention sufficient of these counterfeits already. This colour, too, is prepared from a green chalk, the usual price of it being one sesterce per pound. CHAP. 30.—ANULARIAN WHITE. The other colour is that known as “anularian[1925] white;” being used for giving a brilliant whiteness to the figures of females.[1926] This, too, is prepared from a kind of chalk, combined with the glassy paste which the lower classes wear in their rings:[1927] hence it is, that it has the name “anulare.” CHAP. 31. (7.)—WHICH COLOURS DO NOT ADMIT OF BEING LAID ON A WET COATING. Those among the colours which require a dry, cretaceous, coating,[1928] and refuse to adhere to a wet surface, are purpurissum, indicum, cæruleum,[1929] melinum, orpiment, appianum, and ceruse. Wax, too, is stained with all these colouring substances for encaustic painting;[1930] a process which does not admit of being applied to walls, but is in common use[1931] by way of ornament for ships of war, and, indeed, merchant-ships at the present day. As we go so far as to paint these vehicles of danger, no one can be surprised if we paint our funeral piles as well, or if we have our gladiators conveyed in handsome carriages to the scene of death, or, at all events, of carnage. When we only contemplate this extensive variety of colours, we cannot but admire the ingenuity displayed by the men of former days. CHAP. 32.—WHAT COLOURS WERE USED BY THE ANCIENTS IN PAINTING.