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DYEING AND CALICO PRINTING.

dyeing silk yellow ; the colour produced is pure. Alum is added to the decoc-tion of the root in the dye-beck.

Yellow Colouring Matters contained in Flowers.

Frdmy and Cloez have studied the yellow colouring matters contained in thepetals of flowers, and have found that they contain two pigments, viz., xanthein,soluble in water, and xanthin, insoluble : the last-named substance is bestobtained from the petals of the sunflower ( Helianthus animus), which are ex-hausted with boiling alcohol, from which, on cooling, is deposited the yellowpigment mixed with fatty matters, which latter are removed by saponification.The soap having been decomposed by an acid, the yellow fatty acid isexhausted with cold alcohol, leaving the xanthin as a residue.

Xanthin is an amorphous resinous body, soluble in alcohol and ether, andprobably identical with the pseudocurcumin of M. Schlumberger.

Xanthein, very soluble in water, is readily obtained from yellow dahliaflowers, which for this purpose are first exhausted with alcohol, evaporated todryness, and the residue taken up with absolute alcohol. This solution isfirst diluted with water, next precipitated with acetate of lead, the ensuingprecipitate suspended in water, decomposed by dilute sulphuric acid, thesulphate of lead removed by filtration, and the liquid evaporated to dryness.The xanthein thus prepared is readily soluble in water, alcohol, and ether;alkalies turn the colour a deep brown, but acids restore the yellow again.Xanthein yields coloured lakes with most of the metallic oxides, and dyesbright yellow shades on tissues.

M. E. Schwartz has tried several dyeing experiments with various vegetableprodufls,—among these the blossoms of potatoes, lime-tree leaves and flowers,willow, poplar, horse-chestnut, oak, and other leaves,—with the view to ascer-tain whether these substances might answer as yellow dyes with aluminousmordants, but the results were not encouraging. The finest colours, andalso the richest as regards yield of pigment, were horse-chestnut leaves andpotato blossom (flowers of Solanum tuberosum) ; walnut leaves yield an orange-yellow.

It should be observed that there exist, in almost all parts of Europe, a largenumber of plants, the bloom or flowers of which contain a sufficient quantityof yellow colouring matter to be used for dyeing purposes, especially for olivecolours ; as an instance we name sage (Salvia colorans).

Carotin, Yellow Colouring Matter of Carrot Roots ( Daucus Carota).

This dye has been investigated by Robiquet, Regnault, Zeise, and Huse-mann. The latter prepares carotin by exhausting the previously pulped andrasped root with water; the liquid is precipitated by tannin and a small quan-tity of sulphuric acid; the ensuing pasty precipitate is filtered, washed,pressed, and next exhausted with boiling alcohol at 80 per cent, which takesup mannite and a white-coloured substance, hydrocarotin, C18H30O. Theresidue, insoluble in alcohol, is treated with sulphide of carbon, the ensuingsolution evaporated, and the dry residue treated with absolute alcohol. Thissolution yields, on concentration, a precipitate of carotin as a brown-red, crys-talline, bulky substance, with a metallic reflex. It is soluble in benzol andsulphide of carbon, but insoluble in water and alcohol. This body becomes