Ultramarine
a brilliant blue color, in very extensive use by painters, obtain an equally valuable product by rare, and much prized for ornamental in- laying, and the color being of unap- proachable brilliance and depth, it was an extremely expensive pigment. In conothers. The substance previous to the year 1828 was obtained only from lazulite mineral substance. The mineral being an extremely expensive pigment. In conrare, and much prized for ornamental insequence, strenuous efforts were made to laying, and the color being of unapproachable brilliance and depth, it was ciété d'Encouragement pour l'Industrie obtain an equally valuable product by artificial means. In 1824 the French So- Nationale offered a premium of 6,000 in 1828 the prize was awarded to M. marine blue, possessing all the qualities of that extracted from lapis lazuli, made was declared by competent judges in 1828 the prize was awarded to M. to be in every way equal to the natural product; and Horace Vernet, who was one of the first to use the material, after employing it in his famous picture, Guimet of Lyon, who after four years' investigation succeeded perfectly in promade was declared by competent judges to be in every way equal to the natural li, and t; and Horace Vernet, who was product; one of the first to use the material, ultramarine of the highest quality. His process was never made public; but in after employing it in his famous picture, continued since that time to manufacture "The Battle of Fontenoy," declared the substance to be even superior to natural ultr process was never made public; but in ultramarine of the highest quality. His chemist, made public a process for manuthe same year, 1828, Gmelin, a German chemist, made public a process for manu- facturing ultramarine, which was exten- sively taken up and worked in Germany. facturing ultramarine, which was extensively taken up and worked in Germany. These two discoverers may thus be fairly credited with the joint honors of this most brilliant triumph of chemical research.
The composition of artificial ultraits color, the latter showing many tones marine varies considerably, as does also of and violet, and there is fur manufacture. It is prepared by first disof blue and violet, and there is furtained in an intermediate stage of the solving silica in caustic soda, to which hydrate of alumina is then added in the with an equal weight of sublimed sulphur solving silica in caustic soda, to which hydrate of alumina is then added in the proportion of 30 of alumina to 35 of silica. The mixture is dried and mixed and to this again is added a mixture of equal parts of sulphur and sodic carbonate, weighing as much as the silica and alumina mixture. The whole is then submitted for two hours to a red heat in closed crucibles, whereby green ultramarine is produced and this is again heated and the United States. in crucibles till the desired blue hue is extensively in Germany, France, Belgium ULTRAMONTANISM