We have occasionally found Mars yellow mixed with orpiment, or chromate of lead, for the purpose of brightening the colour. 39. NAPLES YELLOW Was a compound of lead and antimony, anciently prepared at Naples under the name of _Giallolino_, and was variously of a pleasing light, warm yellow tint. It was opaque and of good body, not altered by the light of the sun, and might be used with comparative safety in oil or varnish, under the same management as the whites of lead. Like these, however, it was liable to change even to blackness by damp and impure air when employed in water. Iron was also destructive of the colour of this yellow, on which account great care was requisite, in grinding and using it, not to touch it with the common steel palette knife, but to compound its tints with a spatula of ivory or horn. For the same reason, it was apt to suffer in composition with ochres, Prussian and Antwerp blues, and other pigments of which iron was a principal or ingredient. Used pure or with white lead it was eligible in oil, in which it worked and dried well. It was also employed in enamel painting as it vitrified without change. In this state it was called _Giallolino di fornace_, and was introduced as a pigment for artists, under the erroneous conception that vitrification gives permanence to colours, when in truth it only increases the difficulty of levigation, and injures their texture for working. We have spoken of Naples yellow in the past tense, because the pigment now sold as such is generally, or always, a compound colour, or manufactured with a zinc instead of a lead base. In either case the preceding remarks are not applicable to the present product, which is perfectly durable and trustworthy. The new Naples yellow presents an example of an old objectionable pigment being replaced by a different and superior preparation. However fugitive certain colours may have been, the fact of their once having had a place on the palette would seem to be sufficient recommendation to some. At any rate, they are still in occasional request, and we cannot but approve the pious fraud which offers under the same name a good substitute for a bad original. If an artist must needs demand a worthless pigment, he had better buy a colour like it that will stand, even if it be not what he asked for. The tints of Naples yellow are readily and accurately imitated by admixture of deep cadmium yellow and white. 40. ANTIMONY YELLOW, As its name denotes, was likewise a preparation of that metal, of a deeper colour than Naples yellow, but similar in its properties. It was principally used in enamel and porcelain painting, and differed greatly in tint. One variety, brighter than the rest, is stated not to have been affected by foul air, and therefore could not have had a lead basis. OCHRES,