Orange Vermilion is a bisulphuret of quicksilver, or vermilion of an orange colour, newly introduced: it resembles red-lead in appearance, but is not subject to its changes, being a perfectly durable pigment under every circumstance of oil or water painting. Its tints are much warmer than those of red or orange lead; and it is a most powerful linger of white, yielding purer and more delicate warm carnation tints than any known pigment, much resembling those of Titian and Rubens: and it may be employed safely and with excellent effect in scumbling of flesh, for which Sir Joshua Reynolds improperly used red orpiment. It is the best and only unexceptionable orange we possess, drying in simple linseed oil, and having the powerful body and properties of the other vermilions, and may be tested in the same manner. It works with best effect in water with a considerable portion of gum. The orange of the definitive scale, page 39, is of this pigment.