_Violet de Mars_, _Purple Ochre_, or _Mineral Purple_, is a dark ochre, native of the Forest of Dean in Gloucestershire. It is of a murrey or chocolate colour, and forms cool tints of a purple hue with white. It is of a darker colour than Indian red, which has also been classed among purples, but has a similar body and opacity, and generally resembles that pigment. It may be prepared artificially, and some natural red ochres burn to this colour. Being difficult and sometimes impossible to procure, Mars violet is often compounded; in which case it is liable to vary both in hue and stability. As, however, Indian red is always taken for its basis, the mixture is never wholly fugitive, nor exhibits any very glaring contrast on exposure. 212. MIXED PURPLE. Purple being a secondary colour, composed of _blue_ and _red_, it follows of course that any blue and red pigments, which are not chemically at variance, may be employed in producing mixed purples of any required hue, either by compounding or grinding them together ready for use, or by combining them in the various modes of operation in painting. In such compounding, the more perfect and permanent the original colours are, the more perfect and permanent will be the purple obtained. To produce a pure purple, neither the red nor the blue must contain or incline to yellow; while to compound a durable purple, both the red and the blue must be durable also. Ultramarine and the reds of madder yield beautiful and excellent purples, equally stable in water or oil, in glazing or tint, whether under the influence of light or impure air. Cobalt blue and madder red likewise afford good purples; and some of the finest and most delicate purples in ancient paintings appear to have been composed of ultramarine and vermilion, which furnish tints equally permanent, but less transparent than the above, and less easily compounded. Facility of use, and other advantages, are obtained at too great a sacrifice by the employment of perishable mixtures, such as the lakes of cochineal with indigo. PERMANENT REDS. | PERMANENT BLUES. | Cadmium Red. | Cerulian Blue. Liquid Rubiate. | Cobalt Blue. Madder Carmine. | Genuine Ultramarine. Rose Madder. | Brilliant Ultramarine. Mars Red. | French Ultramarine. Ochres. | New Blue. Vermilions. | Permanent Blue.