It is the chief material used in colouring red rubber.

Vermilion prepared from the mineral or native cinnabar is probably less liable to change than the artificial products, whether obtained by the dry way or the moist way; but 'moist way' vermilions are certainly the most alterable. And it may also be remarked that the more finely a vermilion is ground, the less stable it is - at least, as a water-colour paint. Thus it happens that, other things being equal, an orange-vermilion is inferior in permanence to a scarlet, and a scarlet-vermilion to one inclining to crimson. As an oil-pigment, vermilion does not dry well, but suffers, especially if it be locked up in copal or paraffin, no change by light or impure air; 100 parts of the dry substance require less than 20 parts of oil. Owing to its great density, vermilion tends to separate from the oil with which it has been ground. This result may be obviated by the addition to the oil of a little aluminium oleate or linoleate, or by the employment of oxidized and thickened oil in which a small quantity of beeswax or ceresin has been dissolved by the aid of heat. In water-colour painting most vermilions are found to be changed on exposure, the solar rays gradually converting the red into the black modification of mercuric sulphide, without, of course, producing any chemical alteration.

This change occurs even in the absence of air and of moisture. Impure air, per se, even if sulphuretted hydrogen be present, does not discolour vermilion.

Anyone who has examined old illuminated manuscripts must have noticed the apparent capriciousness with which the ornaments, and especially the initial letters, painted with vermilion, have been affected. I have more than once observed that, while all the vermilion used in one part of a missal or choral-book has remained red, a leaden hue has spread irregularly over the rest of the work in places where this pigment has been used. This may be due to the use by the illuminator of a sample of vermilion adulterated with minium or red lead, but sometimes to a change in the technique, as a change in the style or handiwork is often associated with the difference above described. In oil-painting there are no permanent pigments, save the copper-greens, with which vermilion may not be safely mixed. Only when it contains impurities, such as free sulphur, does it darken flake-white.

Vermilion prepared from native cinnabar is found perfectly preserved in the flesh-tints of Italian tempera-paintings of the thirteenth and fourteenth and fifteenth centuries. It has stood in the wall-paintings of Pompeii, where it often seems to have been waxed. A comparatively recent but instructive instance of the permanence of vermilion in oil is furnished by a portrait, dated 1758, in the National Portrait Gallery. It represents the painter, Hogarth, with his palette set before him. The second of the dabs of colour thereon is vermilion, perfectly intact. In the same collection there is a portrait by Marc Ghee-raedts of Mary Sidney, Countess of Pembroke, in which the vermilion has stood. This work was painted in 1614. Scores of earlier and later examples might be cited.

The variations in hue observable in different specimens of vermilion are mainly due to the differing degrees of fineness in which the pigment occurs. The coarsest grain corresponds with a crimson hue, and then we have every variety of colour ranging from scarlet to reddish orange or orange. The processes of regrinding and 'washing-over' enable us to obtain the kinds separately. And if we repeat these operations often enough, we may ultimately convert the whole of a crimson vermilion into the orange form. It was formerly supposed that the latter material was a mere scum, or impurity, or at least differed from the crimson kind in composition. When any vermilion is mixed in tint with white, an opposite effect to that of further grinding is produced. For, as the early writer Eraclius states: 'If you mix white with vermiculus, carmine is made' - that is, the hue of the mixture becomes more rosy, and therefore further removed from orange.

Madder: Pink Madder - Rose Madder - Madder Carmine - Madder Red - Rubens' Madder - Madder Purple - Madder Lake - Madder Brown - Carmin de Garance - Laque de Garance - Krapplack.

Some authorities assert that madder was used in dyeing long before its employment in painting. But there is some evidence, derived from 'finds' of pigments and from paintings, that the ancient Greeks and Romans were acquainted with a pink pigment derived from madder, while there are good reasons for believing that such substances were widely known in Europe as early as the thirteenth century. Even in England, such a pigment is almost certainly referred to, under the name 'sinopis,' in the middle of the fourteenth century. Now Alcherius (close of fourteenth century) tells us that 'sinopis is a colour redder than vermilion, and it is made from varancia.' 'Varancia' is clearly garance - that is, madder - the same material being named 'warancia' and 'waranz' in a British Museum manuscript (Sloane, No. 416) which contains recipes of the fourteenth century. Besides 'sinopis' (strictly, a red earth), madder-lake was called, in English account-rolls of the fourteenth century, 'sinopre' and 'cynople.' It is, however, difficult, if not impossible, to ascertain the precise date at which pigments derived from madder came into use in the various schools of painting in Europe. For the nomenclature of pigments has always been somewhat vague, while the evidence furnished by existing pictures does not at present enable us to trace back with absolute certainty the mediæval use of madder paints to an earlier time than the fifteenth century.

Eraclius does not mention madder, nor does Cennini, who lived at a much later time. Mr. R. Hendrie, in his notes to 'Theophilus,' speaks of an English manuscript of the fourteenth century in which directions are given for extracting the colouring matter of 'madyr.' From these directions we are, perhaps, justified in concluding that the preparation of a kind of liquid paint was intended.