The dyeing of textile fabrics . en carefullyexamined under the microscope,a wool fibre is seen to consist ofat least two parts, sometimeseven of three. (1) The external cells appearas thin horny plates or scalesof irregular shape; they arearranged side by side and over-lapping each other, somewhatafter the manner of roof-tiles (Fig. 8). The upperedges are more or less free, the lower are apparentlyimbedded in the interior of the fibre. In merino ivoolthe scales appear funnel-shaped, and fit into each other,each one entirely surrounding the fibre. In hair theyare more deeply imbedded; they also
The dyeing of textile fabrics . en carefullyexamined under the microscope,a wool fibre is seen to consist ofat least two parts, sometimeseven of three. (1) The external cells appearas thin horny plates or scalesof irregular shape; they arearranged side by side and over-lapping each other, somewhatafter the manner of roof-tiles (Fig. 8). The upperedges are more or less free, the lower are apparentlyimbedded in the interior of the fibre. In merino ivoolthe scales appear funnel-shaped, and fit into each other,each one entirely surrounding the fibre. In hair theyare more deeply imbedded; they also lie flatter, andpresent but little free margin. This surface-character plays an important ])art incausing the felting of wool in milling, etc. Duringthis and similar operations, in which a large number offibres are brought into close and promiscuous contact,each fibre naturally moves more readily in one directionthan in the other, and the opposing scales graduallybecome interlocked. (2) The cortical substance of the wool fibre. Fig. 8.—Microscopical Appear-ance of Wool Fibre. iCliap. m.] PHYSICAL STRtJCTtfRE OF WOOL. 25 constituting nearly, and sometimes entirely, the wholeinternal portion of the fibre, is composed of narrowspindle-shaped cells, which have assumed a more orless horny character. This structure, which givesthe inner portion of a wool fibre a fibrous appearancewhen examined longitudinally un-der the microscope, is best seenafter gently heating the fibre w^ithsulphuric acid. By means of apair of dissecting needles it is thenreadily separated into its constituentcells. In Figure 9, b represents themicroscopic appearance of the fibreafter treatment with acid, and ashows some of the individual cells. It is an interesting fact thatthese disintegrated internal cellspossess a greater attraction for colour-ing matter than the external scales,and the beneficial efiect of theacidity of the bath, required in manycases of mordantmg and dyeing,may possibly -be ascribed to t
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectdyesanddyeing, bookye
