The Triumphs of Science. - Ultramarine or Lapis Lazuli.

Scientific American 27, 25.3.1848

This is a fine azure blue mineral and has been known in the arts from time immemorial. The rich and unfading blue of the ancient painters was made from this. The finest specimens of it were brought from China, Persia and Great Bucharia and the proposed pigment sold at an enormous price.

"But of all the achievements of inorganic chemistry," says Liebig, "the artificial formation of lapis lazuli is the most brilliant and the most conclusive. This mineral, as presented to us by nature, is calculated powerfully to arrest our attention by its beautiful azure-blue color, its remaining unchanged by exposure to air or to fire, and furnishing us with a most valuable pigment, Ultramarine, more precious than gold?"

The analysis of lapis lazuli represented it to be composed of silica, alumina, and soda, three colorless bodies, with sulphur and a trace of iron. Nothing could be discovered in it of the nature of a pigment, nothing to which its blue color could be referred, the cause of which was searched for in vain. It might therefore have been supposed that the analyst was here altogether at fault, and that at any rate its artificial production must be impossible. nevertheless, this has been accomplished, and simply by combining in the proper proportions, as determined by analysis, silica, alumina, soda, iron and sulhur. - Thousands of pounds weight are now manufactured from these ingredients, and ths artificial ultramarine is as beautiful as the natural, while for hte price of a single ounce of the latter we may btain many pounds of the former.

Wth the production of artificial lapis lazuli, the formation of mineral bodies by synthesis ceased to be a scientific problem to the chemist; he has no longer sufficient interest in it to pursue the subject. He may bow be satisfied that analysis will reveal to him the true constitution of minerals.

(To be continued.)

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