Cork: Its Origin and Industrial UsesStecher, Gilbert Erwin
Science
Cork: Its Origin and Industrial Uses
Stecher, Gilbert Erwin
Cork
The Capgrand-Mothe system, which, as known, consists of dressing the
trunk with the same cork just removed, and leaving it so dressed for a
couple of months, has not met with approval, as being impracticable on a
large scale. After the stripping, the phellogen, the seat of the growing
processes, undertakes at once the formation of a new covering of finer
texture, and each year this, the real skin, with its life-giving sap,
forms two layers of cells, one within, increasing the diameter of the
trunk, the other without, adding thickness to the sheathing of bark.
After eight or ten years this sheathing is removed, and while more
valuable than the first stripping, it is not as fine in quality as that
of the third and subsequent strippings, which follow at regular
intervals of about nine years. At the age of about forty years the oak
begins to yield its best bark, continuing productive as a rule for
almost a century.[19] The cork of the first barking is called
Corcho-Bornio, Borniza or virgin, and is so coarse, rough, and dense in
texture that it is of little commercial value. The second barking is
called “pelas,” or secondary cork, and this and subsequent barkings
constitute the cork of commerce. As the bark is removed it is gathered
up in piles (rusque) and left for a few days to dry. Having been
weighed, it is next carried either in wagons or on the backs of burros
to the boiling station, where it is stacked and allowed to season for a
few weeks. It is then ready for the boiling process. The outside of the
bark in its natural state is, as may well be imagined, rough and woody,
owing to exposure to the weather. After boiling this useless outer
coating is readily scraped off, thereby reducing the weight of the
material almost twenty per cent. The boiling process also serves to
remove the tannic acid, increases the volume and elasticity of the bark,
renders it soft and pliable and flattens it out for convenient packing.
After being roughly sorted as to quality and thickness, the bark is then
ready for its first long journey, and as the forests are generally
located in hilly or even mountainous country, the faithful burro must
again be called into service. Truly the Spaniards’ best friend, though
the worst treated of all, these patient little animals present a most
grotesque appearance when loaded from head to hind quarters with a huge
mass of the light bark. Down from the hills they go in trains of thirty,
forty or even a hundred, threading the rocky bridle paths in single file
and wending their way through the narrow streets of quaint villages
where traces of Moorish occupancy may still be seen, to the nearest
railway station. The corkwood is there freighted to the various sea-port
warehouses in Spain and Portugal, Seville, Spain being perhaps the
largest depository and user of raw material.[20] This historic city,
situated on the banks of the Guadalquivir, presents a very animated
Public-domain text, read in full here on John Shaqi.
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