The Principles of Leather ManufactureProcter, H. R. (Henry Richardson)
History
The Principles of Leather Manufacture
Procter, H. R. (Henry Richardson)
Leather
_Q. Ægilops_ (and probably other species--_Q. macrolepis_, _græca_,
_Ungeri_, _coccifera_), Valonia. Fr. _Valonée_; Ger. _Valonea_,
_Ackerdoppen_, _Orientalische Knoppern_. Best Smyrna contains up to 40
per cent., Greek 19-30 per cent., Candia valonias up to 41 per cent.,
and Caramanian (probably not _Q. Ægilops_) 17-22 per cent. of tannins
which are at least principally pyrogallol derivatives and which give
blue-blacks with iron, no precipitate with bromine-water, and which
deposit a great deal of bloom consisting of ellagic acid.
[Illustration: FIG. 49.--Valonia Oak (_Q. Ægilops_).]
_Q. Ægilops_ (Fig. 49) is said to be most abundant in the highlands of
Morea, Roumelia, Greek Archipelago, Asia Minor and Palestine, while
_macrolepis_ forms large forests in many parts of Greece, and especially
on the lower slopes of Mount Taygetos. In Asia Minor the fruit ripens in
July-August, when the trees are beaten and acorns left on the ground to
dry. They are afterwards gathered, and carried on camels to stores in
the towns, and thence by camel and rail to Smyrna, where they are placed
in heaps 5-6 feet deep in large airy stores, and allowed to ferment and
heat for some weeks, when the acorn, which contains but little tannin,
contracts and falls from the cup, and is used for feeding pigs. This
fermentation is risky, and if carried too far the cups become
dark-coloured and damaged. The acorn contains a considerable amount of
fermentable sugar.
When ready for shipment, the valonia is hand-picked, the largest and
finest cups (prima) going to Trieste, the second selection to England
(Inglese), and the remainder, known as “natural,” also coming largely to
England. The “Inglese,” although inferior in appearance to the very
large selected cups, is, of course, less costly, and gives an equal
yield of tannin.
In 1887, Smyrna exported about 23,000 tons to England, and 16,000 tons
elsewhere, principally to Austria, Germany and Italy. The largest known
crop is stated at 70,000 tons in Asia Minor, and 14,000 in Greece, but
the average yield is considerably less than this.
The beard contains considerably more tannin than the cups, sometimes
over 40 per cent. It is often sold separately at the same or a lower
price, and in Smyrna is known by the Turkish name _tirnac_ (Ital.
_trillo_).
In Greece the best valonia is collected (in April?) before the cup is
matured and while it still encloses the acorn, and is known as _chamada_
(It. _camata_ and _camatina_). The colour of these kinds is excellent
and the percentage of tannin high. Mainly used by dyers, but often worth
attention for tanning where colour is important. In camatina the acorn
is completely covered in the cup, while in camata it is partly exposed.
The next quality, _rhabdisto_, is beaten down by sticks in
September-October (hence name), while after the first rains the fruit
falls and turns black, and is called _charcala_. It contains but little
tannin, and is not generally collected.
Public-domain text, read in full here on John Shaqi.
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