“‘_Preface._--The incitement to this treatise was furnished by the utility of the discovery of Leykauf, instructor of chemistry at the technical schools in Nürnberg, of artificially preparing the well-known blue mineral colour styled ultramarine, according to simple principles, which discovery was supplemented by the production of the green ultramarine, an equally genuine and beautiful green mineral colour, by the technist Heyne in Nürnberg. A short review of the importance of these two discoveries for mankind in general and for science, art, and industry in particular, will form the main subject of this treatise, which has no other object but that of arousing the attention of all high protectors and stimulators, as well as friends of industry and art, to a newly-born industrial branch. At this moment we are living in a period when many industries have got into the stocks, in consequence of far too severe competition, combined with other influences; indeed they are barely able to support those engaged in them. If in consequence of this state of things it already becomes of the most vital importance that fresh sources of acquisition should be obtained, it becomes all the more so when by their means at the same time materials come into requisition which the Fatherland possesses in great superfluity, and which otherwise possess no intrinsic value beyond just the expense of extracting them from their natural localities or deposits, and the worth that attaches to their working up for industrial purpose. A source of acquisition in this sense is met with in the manufacture of blue and green ultramarine colours, which in course of time can be raised to an extremely valuable acquisition. May the communications here made result in their being considered worthy of a thorough many-sided investigation and consideration.’ “REGARDING THE WORK ITSELF. “Page 21.--‘Not long since a prize of 6000 francs was offered by the “Société d’Encouragement.” This prize was gained by Guimet, who has not published his process, and who now furnishes ultramarine at the price of 25 francs per oz., whereas it otherwise cost 200 francs per oz. Latterly, in 1839, Guimet reduced his price for ultramarine, viz. No. 1, for painting, to 10 francs, a lighter shade being 6 francs per oz. In addition, this manufacturer furnishes lower qualities for carpet and paper manufacturers at 20 francs and 12 francs per lb.’ “Page 23.--‘Indeed, if we are able to produce ultramarine by means of a polysulphide of sodium and common clay, then the most beautiful and most lasting of all known blue colours would at the same time become the cheapest of them all.’ “Page 27.--‘All faults which are known to exist in the old methods are obviated in the new invention of Leykauf and Heyne, while the same offers the following advantages:--