or Monicon, is an iron ochre, being a compound of raw Sienna and Roman ochre burnt, and having all their qualities. It is rather more russet in hue than the pigment known as orange or burnt Roman ochre, has considerable transparency, is rich and durable in colour, and furnishes good flesh tints. As in orange ochre, powdered nitre may be employed in its preparation. Notwithstanding its merits, it is obsolete or nearly so; doubtless because burnt Sienna mixed with burnt Roman ochre sufficiently answers the purpose. 167. _Gamboge Orange._ On adding acetate of lead to a potash solution of gamboge, a rich bright orange is precipitated, which may be washed on a filter till the washings are colourless, and preserves its hue with careful drying. The orange which we thus obtained stood well in a book, but it cannot be recommended as an artistic pigment. Perhaps in dyeing, the lead and gamboge solutions might be worth a trial. 168. _Laque Minérale_ is a French pigment, a species of chromic orange, similar to the orange chromate of lead. This name is likewise given to orange oxide of iron. 169. _Madder Orange_, or Orange Lake. It has been said that the yellows so-called produced from madder are not remarkable for stability, differing therein from the reds, purples, russets, and browns. Like them, this 'orange' is of doubtful colour and permanence, and not to be met with, brilliant and pure, on the palette of to-day. The russet known as Rubens' madder has a tendency to orange. 170. _Orange Lead_, of a dull orange colour, is an orange protoxide of lead or massicot. Like litharge, it may be employed in the preparation of drying oils, and, being a better drier than white lead, may be substituted for it in mixing with pigments which need a siccative, as the bituminous earths. Minium sometimes leans to orange; and there is made from ceruse a peculiar red, _Mineral Orange_. _Orange Orpiment_, or Realgar, has also been called Red Orpiment, improperly, since it is a brilliant orange, inclining to yellow. There are two kinds, a native and an artificial, of which the former is the _sandarac_ of the ancients, and is rather redder than the latter. They possess the same qualities as pigments, and as such resemble yellow orpiment, to which the old painters gave the orange hue by heat, naming it alchemy and burnt orpiment. Orange orpiment contains more arsenic and less sulphur than the yellow, and is of course highly poisonous. It is often sophisticated with brickdust and yellow ochre. 172. _Thallium Orange_