TURKEY-RED.

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to the mixture of oil and alkali, it being thought that these materials animalisethe cloth ; but it is more probable that since these materials contain principlesof bile in a high statfe of activity they exercise some influence tendingto a peculiar decomposition of the oil, while, moreover, the albuminouscompounds present aid the formation of the emulsion. Be this as it may,the doth—after having been uniformly worked about and padded in themixture, as described—is dried in a stove-warmed room, and next placedon the grass, or, if the weather be hot and fine, the cloth is at .once dried inthe sun. The joint adtion of a suitable temperature with air, light, moisture,and the alkaline carbonates, brings about a transformation of the oil in apeculiar manner, the true nature of which is unknown to us. Instead there-fore of entering into hypothetical discussions on this subjedt, we prefer to laybefore our readers the results of the experimental researches made by somechemists, among whom is M. Weissgerber, assistant to the late M. Persoz.He took oiled and cleansed cloth, and exhausted it by means of aceton.After repeatedly applying this fluid to the cloth, he observed that it lost moreand more the property of attracting the colouring matter of madder from thedye-beck. On evaporating the acetonic solution in the water-bath he obtaineda viscous liquid residue, which was found to consist of two substances,—onea solid body, the other a liquid. This latter did not, on being saponified,yield even the slightest trace of glycerin, and when the original liquid wasapplied to cloth it dyed up beautifully in the beck with madder.

Dr. Schiitzenberger has recorded the following experiments :—He took clothdyed and cleared for Turkey-red, and treated it at a gentle heat with very strongalcohol acidified with sulphuric acid. The liquid thus obtained was saturatedwith ammonia, the alum precipitate separated by filtration, the solution nextconcentrated by evaporation and precipitated by the addition of water. Thesubstances thus thrown down were removed by filtration, and, after washingand drying, were exhausted by means of sulphide of carbon, which dissolvesonly fatty matters, leaving a residue of pure alizarin. On removing the sul-phide of carbon by evaporation there remained an oily, slightly reddishresidue, a portion of which, when brought into contact with baryta-water,yielded at once, even in the cold, a barytic soap. Hence it is evident that thefluid in question contains a fatty acid in a free state. Another portion of thisfluid was found to saponify very readily with hydrate of baryta, with the aidof heat, but there was left a non-saponifiable material, in all probability thesame substance found by M. Weissgerber. The barytic soaps were readilysoluble in alcohol, and separated therefrom in acicular crystals.

Since it is a well-known fadt that sulpholeic acid, as obtained by the saponi-fication of oils with sulphuric acid, when decomposed by means of water,yields a substance endowed with the property of rendering madder coloursextraordinarily fast when mixed with mordants, it is very probable that theoleine of the Gallipoli adts essentially in producing such an organic mordant.The modified Gallipoli oil adts therefore—(1), as a mordant, because, accordingto the researches of Prof. Chevreul, some Turkey-reds contain only a verysmall proportion of alumina; (2), as fastener of the red lake ; (3), it has beenproved by Kuhlmann that it has the property of precipitating and energeticallyretaining several metallic oxides, as, c.g oxide of iron. This may be readilyproved by simply dipping previously oiled cloth into a solution of a per-salt of•ron, to obtain, on dyeing it afterwards with madder, a beautiful purple colour,