The principles of leather manufacture by Procter Henry Richardson 1848-

Author:Procter, Henry Richardson, 1848-
Language: eng
Format: epub, pdf
Tags: Leather industry and trade
Publisher: London, Spon
Published: 1903-03-25T05:00:00+00:00

246 PRINCIPLES OF LEATHER MANUFACTURE.

Space does not permit of any detailed account of the structure of fruits, wood and leaves, which are also cellular structures in many respects resembling the bark. The cuticles of leaves, and especially the stomata or breathing pores, and the hairs are often very characteristic. (Cp. Plates III. and IV., and p. 272.)

Valuable hints may also be obtained from the chemical reactions which are described on p. 70 et seq., L.I.L.B.

BOTANICAL LIST OF TANNING MATERIALS.*

CONIFERS, Pines, Cypresses, mostly containing Catechol tans, yielding reds.

Abies excelsa, Lam. (Pimis Abies, Pinus Picea, Picea vulgar is, Link.), Norway Spruce. Fr. Faux sapin ; Ger. Fichte, Rottauuc. The source of the so-called larch-extract, and a principal tanning material of Austria. Contains 7-13 per cent, of a catechol-tannin and much fermentable sugar, and on this account is useful for swelling and colouring, but does not tan heavily. English and Scandinavian bark does not seem much utilised. Best bark 2-8 mm. thick; smooth, yellow inside, with reddish-brown ross outside. For detailed description of structure see von Hohnel, ' Die Gerberinden,' p. 35.

Abies pectinata, Silver Fir. Fr. Sapin; Ger. Edeltanne, Silbertanne, Weisstanne. Used to a limited extent, but apt to be confused with spruce. Contains6-15 percent, iron-blueing tannin. Used in Styria, Austria, Russia. Without " ross," but silver-grey and smooth outside. (Von Hohnel,' Die Gerberinden/ (p. 40; 'Gerber,' 1875, p. 375.)

Abies (Pinus, Tsugd] canadensis, Hemlock Fir (Fig. 44). The principal American tanning material, and source of hemlock extract; averages 8-IO per cent, of a catechol-tannin, but variable, 18 per cent, reported, possibly from a different species. Abundant in Canada and the Northern and North-western States of America. The bark of old trees, which is principally used for tanning and extract-making, is 2-4 cm. thick, smooth and yellow

* The percentage of tannin given where the source of information is not stated must in many., cases be regarded as uncertain, many analyses having been made before the introduction of modern methods, but those quoted as having been done in the author's laboratory are of recent date and have been made by the latest methods.

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