or _Tungstate of Baryta_. "At the request of a landscape painter," says M. Sacc in a letter to M. Dumas, "I was induced to examine in succession all our insoluble white compounds, with regard to their adaptability to painting purposes. Tungstate of baryta answers perfectly, covers as well as white lead, and is as unalterable as zinc white. It has been employed by this artist for three months, and was found equally successful in oil or water colours, chromolithography, and even in making white impressions on a black ground. This harmless substitute for the injurious white lead is prepared on a large scale in Paris by M. E. Rousseau." We have not met with a sample of that gentleman's manufacture, but judging from our own specimens, made both by wet and dry processes, and carefully tried in water and oil, it would seem that a perfect white pigment has yet to be discovered. With us, at least, tungstate of baryta is far from having the body of white lead, and indeed is inferior in opacity to good zinc white. Unaffected by foul air, the tungstate appears to possess the common fault of all whites when compared with white lead--want of body, moreover it is a bad dryer. However, M. Rousseau's preparation may not be open to these objections, and we therefore reserve our final opinion of tungsten white. It is intended to publish from time to time a fresh edition of Field's Chromatography, and we hope in the next issue to give a more detailed and favourable account of the new pigment. INDEX. A. Acacia catechu, 354. Academy, Royal, at Burlington House, 365. Acetate of lead, as a siccative, 51. " improper use of, 52. Adulteration, 70. " of Anotta, 256. " Artificial Ultramarine, 214. " Black Lead, 394. " Cadmium Yellow, 88. " Carmine, 134. " Chrome Yellow, 94. " Cochineal, 132. " Genuine Ultramarine, 214. " Indigo, 202. " Ivory Black, 397. " Madder, 140. " Madder Carmine, 142. " Mars Yellow, 102. " Prussian Blue, 203. " Red Lead, 152. " Smalt, 198. " Verdigris, 276. " Vermilion, 156. " Veronese Green, 268. " White Lead, 70, 74, 75. " Yellow and Orange Orpiment, 113, 259. " Zinc White, 77. Advancing and retiring colours, 186-188. Advice, Cennini's, 411. Aerial perspective, 22. African cochineal, 170. " green, 271. Air and light, action of, on pigments, 39. Air effect, want of, 378. Albumen, 50. Alchemy, 259. Alexander the Great, 296. " Veronese, 284. Alkanet, 302. Almagra, 147. Almond Black, 407. American artist, an, 347. Analysis of Brown, 377. " Citrine, 329. " Gray, 377. " Marrone, 377. " Olive, 330. " Russet, 330. Anchusa tinctoria, 302. Ancients, colouring of the, 3. " colours of the, 5, 6, 218. Aniline, 162. " colours, 162. " " cakes of, 163. " " in oil, 247.