The Metropolitan 10, 1831
By M. Lassaigne.
— Several mineral compounds, remarkable for a lively and durable colour, as well as for their unalterability on exposure to light, have been already applied to dyeing certain tissues: such are, among others, hydro-ferrocyanate of iron (Prussian blue), yellow sulphuret of arsenic (orpiment), and chromate of lead. Some of these applications are at present made, even in the large way, with advantage in several factories or dye-houses; and it is probable that eventually, as new experiments may show, the number of colouring substances derived from the mineral kingdom, which maybe employed in dyeing, will increase. If the results which we presented to the Academy of Sciences last year, can find no direct application at this moment, we shall have at least fixed the attention of chemists on several facts, some of which were, we believe, at that time unknown. Among the metallic compounds which possess the property of being coloured by themselves, we have tried a series of experiments with a view to fix them on different textures or cloths. Some have yielded negative results, and on a small number only have we as yet had the satisfaction of succeeding. The sulphuret of cadmium, the colour of which, in a state of purity, is so vivid and beautiful, has particularly engaged our attention. This compound, the knowledge of which is a consequence of the discovery of cadmium, may be fixed on silk, as we have observed, by first impregnating that substance with a certain quantity of the chloride of cadmium, and putting it afterward in contact with a weak solution of hydrosulphate of potash or of soda. It is easy to perform this operation by holding the silk immersed in a solution of chloride of cadmium, at a temperature of 50° or 60° (from 120° to 140° Fahr.), during 15 or 20 minutes, wringing it afterward, and putting it in contact at the common temperature, with a dilute solution of hydro-sulphate of potash in water. As soon as the silk is immersed in this liquor, it takes a golden yellow tint from the sulphuret of cadmium which is produced, and which remains intimately combined with the substance of the silk. According to the quantities of the chloride of cadmium which are applied on the silk, it is possible to obtain different shades from pale yellow to orange or golden yellow. This dyeing by sulphuret of cadmium is unalterable by solar light. Weak acids and diluted alkaline solutions in water do not occasion any change. The facility with which silk may be dyed by the process above-mentioned should allow it to be presumed, that if the cadmium were to become more common, not only its sulphuret would be employed in painting, as already proposed, but the art of dyeing might use it to advantage for dyeing certain manufactures of silk of a brilliant yellow colour, unchangeable by air and light. The giving of colour to textures by this new mineral compound, would not have the inconveniences which are naturally attached to the yellow dyes by sulphuret of arsenic and chromate of lead. The trials which we have made on wool have proved to us that this substance does not possess, like silk, the property of readily taking a dye from sulphuret of cadmium; perhaps success might be attained with it, by modifying the process we have employed with silk.
— Annales de Chimie
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