Is a pigment long employed in India under the name _Purree_, but has not many years been introduced generally into painting in Europe. It is imported in the form of balls of a fetid odour, and is produced from the urine of the camel. It appears to be a urio-phosphate of lime, and is of a beautiful pure yellow colour and light powdery texture; of greater body and depth than gamboge, but inferior in these respects to gallstone. Indian yellow resists the sun's rays with singular power in water painting; yet in ordinary light and air, or even in a book, the beauty of its colour is not lasting. In oil it is exceedingly fugitive, both alone and in tint. Owing probably to its alkaline nature, it has an injurious effect upon cochineal lakes and carmine when used with them. The colour is not damaged by foul air, and, as lime does not destroy it, the pigment may be employed in fresco according to its powers. Indian yellow washes and works extremely well, and is adapted for draperies and for compounding landscape greens--where permanency is not required. Blackness in the darkest shadows of the foliage will sometimes result from too great a use of indigo; should this evil exist, no colour is so fitted to regain the proper tone as Indian yellow employed thickly. LAKES. There are several pigments of this denomination, varying in colour and appearance according to the substances used and modes of preparation. Usually they are in the form of drops, and their colours are in general bright yellow, very transparent, and not liable to change in an impure atmosphere--qualities which would render them very valuable, were they not soon discoloured and even destroyed on exposure to air and light, both in water and oil. In the latter vehicle, they are bad driers, like most lakes, and they do not stand the action of white lead and other metallic pigments. If used, therefore, it should be as simple as possible. Of these lakes, the following are the best; but it must be borne in mind that, as not one of them is permanent, the compounds they afford are of necessity unstable. 34. YELLOW LAKE Is a bright transparent yellow, a difficult drier, and liable to be destroyed by light. It affords beautiful foliage tints, and would, if it could be depended on, be of extreme value in what is called "glazing." 35. ITALIAN PINK, Also called _English_ and _Dutch Pink_, is an absurd name for a stronger and richer kind of yellow lake, warmer in tint and more powerful than the preceding. It is a rich transparent yellow, yielding a variety of fine foliage tints by admixture with indigo and sepia in different proportions. These three colours with burnt sienna will produce almost every variety of sunny foliage. It gives likewise good olive greens with lamp black. 36. QUERCITRON LAKE,