83
[Class IV.
obtained. with alum. Madder is the colouring matterused in the Turkey red dye, so celebrated for brilliancyand permanency.
10. Sumach, from Sicily ;—is a small plant, the Iihuscoriaria. The sumach is exhibited as ground for thedyer’s use; also its black precipitate with iron,—yellowwith tin,—yellow with alum. •
17. Weld;—grown in Great Britain and the north ofEurope; is a small plant , the Reseda Inteoki, a specimenof which is exhibited. It is used as a yellow dye, or asa component of green. Its aqueous extract and yellowprecipitate with alum are-shown.
18. Persian berries, from the Levant ;—the berries of ;the Rhamnus infectorius, which afford a yellow dye. Theyare exhibited as gathered. Also the aqueous extract andthe colouring matter precipitated,—yellow with alum andwith tin.
artistic excellence. But in combination with these dyeingmaterials, and illustrating the subject as a whole, areexhibited samples of skein-dyeing by three London dvers—by Mr. Ciiarot on wool, by Mr. Reynolds on silk,and Mr. Brncn on cotton : these may be taken as a fairsample of the uses to which the dyers of London put thevariety of drugs and substances we have enumerated. Indy eing the skein previously to the threads being woven,Mr. Burch, who shows all his productions in this com-bination, exhibits also a scries of dyes in “ fast colours”on Lisle thread, which are used for the cotton glovemanufacture, in which the ordinary dyes are sadly toofugitive; also a series of dyed lace cotton, dressed by apeculiar process to resemble the hard-thrown maraboutsilk, which is extensively used in the manufacture ofvelvet, gauze ribbons, and other fabrics in which a firm-ness of texture is desirable.
19. Turmeric, from the East Indies;—the root of theCurcuma lomja. It is exhibited as a root, and in theground state as used by dyers. It affords of itself, with-out a mordant, a yellow dye, which is brilliant, but un-fortunately not very permanent, samples of which areshown.
21. Orchil; — (Roccella tinctoria'), from the CanaryIslands , is a lichen, which grows on the rocks by thesea-shore. The plant is of a pale-stone colour, but yieldsa magnificent purple matter, which fixes in wool and silkwithout a mordant. It is reddened by acids, and ren-dered blue by alkalies, thus affording a great variety oftints. Its aqueous purple solution is shown, with samplesof dye on silks and wool.
22. Annatto, from South America ;—an orange colour-ing matter obtained from the seed of the Bixa Orellana.The colouring matter is brought to this country in massesenveloped in rushes. It is soluble in alkalies, by whichmeans it is fixed in the cloth. The annatto is exhibitedas a mass, with samples of its dyes.
23. Safflower; — from Egypt, the Levant, SouthernAsia , &c.,; the dried petals of the Carlhamus tinctoria,from which is obtained a very beautiful colouring matter,that attaches itself without a mordant, and is extensivelyused in silk and cotton for a variety of shades of pink,rose, crimson, scarlet, &c., but which, unfortunately*, doesnot possess the power of resisting the action of soap. Thesafflower as imported is exhibited; also the alkaline ex-tract precipitated a fine rose-colour by an acid, with dyedsamples on cotton and silk. This colouring matter is notsuitable for wool.
24. Cochineal, from Mexico ;—is a small insect, a va-riety of Coccus, which lives upon different species of theCactus opuntia or nopal. It affords a fine red colouringmatter, which is extensively used on silk and wool, par-ticularly the latter, the whole range of the best red dyeson wool being due to the colouring matter of this insect.The two varieties exhibited are known in commerce asthe “black grain” and “silver grain;” terms whicharose from the fact that, when first imported, this insectwas considered to be a seed or grain, and its dyes werespoken of as “grain” colours. The aqueous and ammo-niacal extracts of the colouring matter are shown, alsothe colouring matter precipitated with tin and with alum.It forms very fine and permanent dyes in reds, crimsons,scarlets, &c., samples of which are shown on wool andsilk. It is not applicable as a dye for cotton.
25. Lac-dye, from India ; — the colouring matter of.“ lac,” a substance formed on the branches of various 1trees by the puncture of a small insect, similar to cochineal, :the Coccus lacca. The resinous matter, being separated,forms the “shellac” of commerce, and the colouringmatter, the lac dye, is thus obtained. It is used as ared dye on wool, but its colour is inferior to that from 'cochineal. The dye is exhibited, with dyed samples. 1
Having thus briefly enumerated the substances ex- :hibited, it may be observed that the dye samples showmerely those colours which result, entirely and directly,from the substances in connexion with which they areplaced; and do not, in fact, truly" represent the art of:dyeing, which frequently depends on a nice mixiug oftints, and is effected by the combination of several,—perhaps many,—substances, in order to the attainment of
Some excellent illustrations of the native vegetabledyes of Scotland are shown in Messrs. Lawson’s valuablecollection (Class III., 105, p. 200). These are nownearly all superseded by cheaper and more brilliant dyesof tropical countries.
A very good series of samples of superior orchil, cud-bear, and other preparations of lichens, is exhibited by-Messrs. Smith & Son (68, p. 200*), accompanied by spe-cimens showing the colours dyed with them. The Jurydeemed these dyes of superior excellence, and accordinglyawarded a Prize Medal for them.
A highly-complete and instructive series of lichen pre-parations is exhibited by Wood & Bedford (Class II.,47, p. 192), including the chief varieties of lichens knownin commerce, the colouring matters prepared from them,the different peculiar colouring and other principles con-tained in them, or obtained from them by chemical pro-cesses, and illustrations of the practical uses of lichendyes to silk, feathers, wool, leather, marble, wood, &c.The chief lichens employed in the manufacture of orchiland cudbear are the following :—
Commercial Niimr*. '
Lima weed - -Valparaiso weed
Cape weed — —
I Whence Imported.
Kainalina furfuracea - :Rocella fuciformis <
Ilocella tinctoria — |
Parmelia perl at a — —Parmelia tartarea . —Vmbilicaria pustulataGyrophora murina -
Of these nine lichens, the first grows as a parasite upontrees; all the remainder upon rocks: the first is therichest in colouring matter. The samples of cudbear andorchil shown are numerous, and well illustrate the gradualdevelopment of the colour: the whole collection is highlycreditable, and the Jury, therefore, awarded a PrizeMedal for it.
Specimens of safflower, and good illustrations of its usein dyeing silk, are shown by Long & Reynolds (75,p. 205*) : these were deemed deserving of HonourableMention.
Good specimens of several dye-stuffs are exhibited byJ. Marshall, of Leeds (Class II.. 68, pp. 194, 195), in-cluding cudbear and orchil, turmeric, and an interestingseries of lac-dye : these also were deemed worthy ofHonourable Mention.
A sample of chicory woad is exhibited by Saundersand Gatchf.ll, of Dublin (71, p. 200*). It is statedthat this substance, which can be used as a blue dye inthe place of real woad, may be profitably grown and soldat about Si. per ton, the price of real woad varying from20/. to 30/. per ton.
A large and highlv-valuable collection of dye-stuffs isexhibited by the Hon. East India Company , includingspecimens of the well-known dyes of India , and also ofa large number of new and little-known substances em-