Mr. H. G. Glasspoole,[31] writing regarding the uses of cork by the
ancients, states: “The cork-tree, and the application of its bark to
useful purposes, was well known to the Egyptians, Greeks and Romans. The
former used this material in the construction of the coffins for their
dead. Theophrastus, the Greek philosopher, who wrote on botany four
centuries B.C., mentions this tree among the oaks, under the name of
‘Phellus’ in Book Two of his ‘Historia Plantarum,’ and stated that it
was a native of the Pyrenees, having a thick fleshy bark which must be
stripped off every three years to prevent it from perishing. He adds
that it was so light as never to sink in water, and on that account
might be used for many purposes.” It is the opinion of the writer that
the attention of the ancients was undoubtedly called to this particular
bark by its buoyancy, and as their fisheries were extensive its
usefulness became readily apparent to float nets, etc., or to use
even in the construction of their boats, and its sponginess and
water-repellent properties not escaping their notice, it became a most
likely material for stoppers of casks or amphorae as noted by Horace in
Ode iii, 8: “Corticem adstrictum pice dimovebit amphorae.” Pliny, in his
“Natural History,” XVI, 18, describes the tree under the name of Suber
and relates everything said by Theophrastus of Phellus. From his account
we learn that the Roman fishermen used it as floats to their nets and
fishing tackle, and as buoys to their anchors. The use of these buoys in
saving life appears to have been well known to the ancients, for Lucian,
Epist. i, 17, mentions that when two men, one of whom had fallen into
the sea, and another who jumped after to afford him assistance, both
were saved by means of an anchor buoy. The use of this substance in
assisting swimmers was not unknown to the Romans, for Plutarch in his
Life of Camillus, who flourished in Rome 400 B.C., gives an account of
its use by a messenger, sent to the Capitol, then besieged by the Gauls:
“Pontius Cominius having dressed himself in mean attire under which he
concealed some pieces of cork. He could not pass the river by the
bridge, therefore took off his clothes, which he fastened upon his head,
and having laid himself upon the pieces of cork swam over and reached
the city.” The use of cork as stoppers was entirely unknown to the
Romans, but instances of its being employed may be seen in Cato’s “De Re
Rustica,” Cap. 120, but this did not happen frequently or more would be
said of it.
[31] _Scientific American Supplement._
The convivial customs of those days had no connection with the bottle,
glass bottles being of a much later invention. Instead of having
champagne or hock to be liberated from the bottle by the corkscrew at
their feasts, the guests filled their drinking cups of gold, silver,
crystal or beechwood from a two-handled amphora, a kind of earthenware
pitcher, in which their choice wines used to be kept. The mouths of
these vessels were stopped with wood and covered with a mastic, composed
of pitch, chalk and oil to prevent air spoiling the wine or evaporation
taking place. Columella, who wrote one of the earliest works on
agriculture, gives directions for preparing this cement.
The employment of cork for stoppers of bottles appears to have come into
use about the seventeenth century, when glass bottles, of which no
mention is made before the fifteenth century, began to be generally
introduced. Before that period apothecaries used stoppers of wax, which
were not only much more expensive but far more troublesome. In 1553,
when C. Stephanus wrote his “Praedium Rusticum,” cork stoppers appear to
have been very little known in France, for he states that this material
was used principally for soles in that country. It is not known when
cork and corks began to be generally used, but in that very amusing and
instructive diary of Mr. Samuel Pepys the following entry is found: “14
July 1666” After having written to the Duke of York for money for the
fleet, I went down Thames Street and there agreed for four or five tons
of cork to be sent to the fleet, being a new device to make barricados
with instead of junts (old cable),” but he does not inform us how the
material answered.[32]
[32] I have subsequently learned that this proved a failure.
In Evelyn’s time (1664) cork was much used by old persons for
linings to the soles of their shoes, whence the German name for it,
“Pantoffelholtz” or slipper wood. The Venetian dames, Evelyn says, used
it for their choppings or high-heeled shoes to make them appear taller
than nature intended they should be. The poor of Spain lay planks of
cork by their bedside to tread on instead of carpets. Sometimes they
line the inside of their houses, built with stone, with this bark, which
renders them very warm and corrects the moisture of the air. Loudon
relates that in the celebrated convent at Cintra, Portugal, several
articles of furniture are made of this tree. Virgin cork, or the first
bark of the tree, is now very much used for window flower boxes,
grottoes, etc., while the subsequent grades are used for small
architectural and geognostic models. Cork was formerly employed in
medicine even as far back as the time of Pliny, as he tells us that the
bark of the cork tree, pulverized and taken in warm water, arrests
hemorrhage at the mouth and nostrils, and the ashes of it taken in warm
wine are highly extolled as a cure for spitting blood (see Pliny, “Nat.
Hist.” b. 124). In modern time powdered cork has been applied as a
styptic and hung about the necks of nurses. It was thought to possess
the power of stopping the secretion of milk. Burnt cork mixed with sugar
of lead has been used as an application to piles. See Pereira’s “Materia
Medica.”
Ground cork and India rubber formed the basis of Kamptulicon, the soft
unresounding material which covered the floor of the reading rooms of
the British Museum.” In further describing the many uses to which cork
is applied, reference is made to the résumé of Mr. Good in “La Nature,”
which is incorporated with a few slight changes.
“The various applications of cork that we are now going to pass in
review are worthy of description, as each of such applications has its
_raison d’être_ in one or more of the physical or chemical properties of
cork bark. The manufacture of stoppers utilizes, in the first place, the
impermeability of the bark, and, in the second, the latter’s elasticity
and imputrescibility, the remarkable lightness playing no rôle therein.
Before entering upon a study of the industrial applications of cork, in
grouping them according to the various qualities of this product, we
must return to the “male” cork, derived from the first barking of the
tree. It has been said, because of its slight elasticity and numerous
fissures, this product has but little commercial value, and shall have
mentioned its principal application when we have stated that it is used
in the decoration of parks and gardens. An endeavor has been made, but
without success, to manufacture from it, mills for decorticating rice.
Certain parts of it can be converted into small stoppers. In the country
where it is produced, it is used for making water conduits, beehives and
shelves on which to preserve objects from dampness. Mixed with a mortar
of clay, the Kabyles use it for the walls of their dwellings, and also,
in lieu of tiles, as a roofing material for their primitive habitations.
It is used also by fishermen as floats for their nets.
These various applications were known to the Greeks and Romans, as shown
by the works of Theophrastus and Pliny. The latter says of the cork-oak:
“Nothing is utilized but its bark, which is very thick, and which is
renewed in measure as it is removed. This bark is often used for the
buoys of anchors and ships and of fishermen’s nets, for the bungs of
casks, and for women’s winter foot gear. The Greeks called the cork-oak
the ‘bark tree’.... Cork bark is used as a covering for roofs.” (“Hist.
Nat.,” xvi, 18.) As for the chips, they can be used as an isolating
material to prevent freezing. Reduced to fragments, they furnish an
excellent material for covering circus rings.
Let us return to “female” cork, which is much better adapted for being
worked, and the grain of which is much more homogeneous. In this form
cork bark constitutes a very bad conductor of heat and sound, and
renders valuable services in the industries as a material for
preventing the cooling of steam pipes and generators, and preventing
the melting of ice in ice houses, or the heating of apparatus for
producing cold.
It is the basis of a certain number of cements, and coatings for
preventing the escape of heat, which are applied to pipes, steam domes,
hot water reservoirs, etc., and upon the composition of which we shall
not dwell here. As for jacketing with cork alone; the first method
consists in placing narrow strips of cork, whose edges touch each other,
along steam pipes and cylinders, and fastening them by means of wire. A
pipe thus jacketed is tangent internally to all these strips, and a
section of the whole shows a circle inscribed in a polygon. In the
second system thin strips of cork, fastened to canvas with India rubber
cement, are wound around the pipe spirally. Finally, a third method of
jacketing consists in the use of two half cylinders that exactly fit the
exterior of the steam pipe. These cylinders, which can be made of any
desired length, are made of powdered cork and starch, and are covered
with a spirally wound strip of calico, which may be coated with tar or
any suitable kind of paint. Each of these systems permits of obtaining a
great saving in fuel.
As cork is likewise a very bad conductor of sound, it is successfully
used on the doors of consulting rooms, and for making floors for
hospitals, etc. Finally, in the manufacture of certain stringed
instruments, it is used to prevent a loss of sound.
The slight density of cork, as compared with water, and its
impermeability to liquids, make it an excellent float, capable not only
of remaining on the surface, but also of supporting quite heavy bodies
thereon. We shall be content to mention the annular cork float used in
night lamps, the square block in which bath thermometers are fixed, and
the fisherman’s dobber.
It is cork, too, that is used by preference in the manufacture of
swimming and life-saving apparatus, to which inventors have devoted much
thought. Very many vessels are provided with cork mattresses, which, in
cases of shipwreck, render the greatest services. For example, the ship
_Constant_, which sailed from Anvers for Brazil in 1845, was wrecked on
the night of October 12th, at twelve miles from St. Thanes, but, thanks
to the cork life preservers and mattresses that she had on board, not
one of the crew was lost. As for life-saving buoys, properly so called,
they consist of several cork planks which are given an annular form, and
are provided with free ropes that are knotted here and there so that
they may be easily grasped. From the stern of every vessel a buoy of
this kind is suspended by a rope that may be at once cut when the cry of
“A man overboard!” is heard. These buoys are usually covered with canvas
coated with a paint that serves to preserve it. It is also possible to
save a person who has fallen into the water at a certain distance from a
wharf by means of floats. This device consists of a piece of rattan
provided with points around which molten lead has been poured, and the
whole is then surrounded with cork in chips, and covered externally with
canvas and a network to protect the affair against wear.
Fenders are canvas bags that are filled with cork and are placed along
the sides of ships or along docks in order to deaden the shock in case
of a collision. Such are the principal uses rendered to navigation by
cork.
It has already been seen, by the extract from Pliny, that Roman ladies
preserved their feet from cold by means of cork soles. Such a use of
cork is still in vogue. In addition to these soles, which are flat,
there are others that have nothing to do with hygiene, and are merely
connected with fashion. Such are the Louis Quatorze talonettes, designed
to increase the stature without exaggerating the heel of the shoe.
Female dancers wear linings of this kind in their shoes, which, as well
known, have flat soles. A thin sheet of cork enclosed in the sole of the
shoe would, we think, prove very useful to troops on a march during bad
weather.
Cork is not only useful as an application to foot gear, but also renders
great service in head gear, and, in the form of helmets, has preserved a
large number of soldiers from death by sunstroke in tropical countries.
We find it again, in the form of very thin sheets, in the interior of
beaver hats, where it is used as a protection against heat. It is also
used in these same hats as a sweat band, in lieu of leather. In ladies’
toilets, the cork serves to make the carcasses of the birds that
decorate their head gear. Manufacturers of dress trimmings use cork
molds, which they cover with silk or cotton, for ornamenting cloaks,
etc. The lightness of cork can alone explain the great size of these
balls, olives, etc., some of which are larger than a hen’s egg.
A few years ago, a Paris house sold cork cravats, and we have recently
seen, exposed in a show case, some children’s costumes, in which the
sailor’s collar was of thin sheet cork decorated with colored designs.
Although cork gowns have not yet appeared, we have waterproofs composed
of thin sheet cork cemented between two pieces of silk. These cloaks
have the advantage over those made of rubber of not allowing air to pass
through them.
There is also a curious application of cork in the manufacture of a
fabric that renders those who are clothed with it insubmergible.
We can mention but few of the many applications of cork, new ones of
which are being discovered every day, so shall confine ourselves to
recalling the services rendered by this valuable product in surgical
prosthesis and for the use of naturalists, etc. In domestic life, it is
used for bath steps, and for making rolling pins for crushing almonds
without absorbing the oils as wood would do. Thin sheets of it are used
for making fancy labels for wines. The ease with which it may be cut,
turned and worked causes it to be employed in the manufacture of small
objects, such as rural landscapes and the reproductions of monuments,
some of which are genuine works of art. We may likewise mention, among
objects made of cork, cases of various forms for sending bottles by
mail, spools for allowing of the cheap carriage of silk, the
old-fashioned inkstand, the thick penholder for preventing writer’s
cramp, the cigar holder and many fancy objects that would take too long
to enumerate. There is perhaps no calling that does not have to make
more or less use of cork. Polishers of gold have used it from time
immemorial, in the form of narrow strips, for rubbing their work with
rouge. The wheels with which crystals are polished are faced with it,
and watchmaker’s lens mounted in cork, the lightness of which prevents
the muscles of the face from tiring.
In the industries, driving pulleys are now beginning to be provided with
cork in order to secure an adhesion of the belting. In carpenter shops
these bands of cork are now advantageously replacing rubber ones for
covering the pulleys over which the band saw runs. The stoppers of
nursing bottles are now being replaced by hygienic ones of cork, which,
being very cheap, can be changed as soon as the presence of ferments is
suspected. Cork is likewise employed in the manufacture of children’s
toys; it serves, for example, for fixing the wig on dolls’ heads. Is it
necessary to recall the cork of pop-guns and pistols, and the cork
battledores and shuttlecocks used for playing with indoors? These few
data will serve to show that but few products are capable of so many
diverse applications as cork is; and the question may be asked whether
it would be possible to substitute anything else for it, in case the
supply should become exhausted.
The manufacture of stoppers and of the various objects that we have just
enumerated furnishes a considerable quantity of chips, which along with
the waste derived from the collecting of the material, and with old,
second-hand corks, constitutes the crude material destined to supply
certain important industries, which, for the sake of completeness, must
be mentioned.
We have first the cork powder industry, which manufactures powders of
various degrees of fineness. The coarsest powder is used for packing
fragile objects, on account of its elasticity, coupled with its
lightness, which permits of a great saving in freight charges.
The finest powder forms, “liegine” or “suberine,” whose balsamic
properties are well known to hygienists, and which may be used as a
substitute for lycopodium, starch and fecula as an application to the
skin of babes. Under the name of “zifa powder,” an insect powder has
been made composed of cork and phenol. Fire lighters have likewise been
made from cork powder; but this and the last named application have not
amounted to much.
We cannot enter into much detail in regard to the manufacture of
linoleum, notwithstanding the interest that it presents. The manufacture
began in Scotland, and is tending to settle in our own country. Linoleum
is made by intimately mixing cork powder with oxidized linseed oil. The
paste thus prepared is spread over canvas if the intention is to
manufacture carpets, but over paper if it is desired to make hangings.
The color of linoleum, which is the same as that of cork, only a shade
darker, can be enlivened by colored designs. When applied to damp walls,
linoleum is capable of receiving oil paintings of a more stable nature
than those executed upon wood, which warps, or upon other building
materials, which crack, such as plaster, for example. It can also be
used for decorated ceilings for public halls, cafes, etc.; and when such
ceilings become black through smoke and dust, they can be washed.
As a carpet, linoleum renders flooring perfectly insonorous. It converts
damp and unhealthy apartments into healthy and warm places of
habitation. Used in kitchens and offices, it has the advantage of not
being spotted by fatty matters. It has been generally adopted in our
naval and merchant ships, where the use of it has given a great setback
to the oil cloth industry.
A new decorative product, “lino-burgau,” obtained by embossing linoleum,
possesses the iridescent reflections of nacre, due to the application of
colored varnish along with a bronzing of certain parts. Notwithstanding
its expensive nature, we believe that there is a great future in store
for it.
The manufacture of agglomerates of cork is becoming very widespread in
France. We have already mentioned the use of artificial cork for
jacketing steam pipes, and we have stated that this product is obtained
by mixing cork powder and starch under pressure. This dried paste can be
given the most diverse forms, and be made of any thickness. Another
substance, called brick paste, is obtained by mixing the coarsest cork
powder with milk of lime, and, after compression and drying,
constitutes, under the form of bricks and slabs, an excellent material
for the construction of party walls, for covering damp walls and sloping
roofs.
In the cellars of breweries, these bricks diminish the melting of the
ice. In gunpowder works, they prevent the caking of the powder through
dampness, and, in case of an explosion, their friability and lightness
lessen the importance of the catastrophe. They are also used as a
foundation for flooring in order to destroy its disagreeable
sonorousness. In the spinning mills of Alsace and the west of France,
they have given excellent results, both as regards their resistance to
the passage of sound, heat and cold, and their cheapness.
Cork chips and waste, when distilled, furnish an illuminating gas that
burns with more brilliancy than that made from coal, and does not, like
the latter, give off sulphureous emanations that tarnish frames and
other gilded objects. The city of Nerac was lighted with cork gas for a
certain length of time, but the use of it had to be given up on account
of the difficulty of storing the chips, which, with but little weight,
took up an enormous space. This gas, in view of its slight density and
its purity, would prove an excellent one for the inflation of balloons.
Finally, cork parings and waste, properly carbonized, produce Spanish or
cork black, one of the most beautiful and durable blacks known in
painting.”
The recent uses for corkwood are, as a float in the carburetter of an
automobile, the cork insert in the periphery of a pulley,[33] cork paper
for cigarette tips, a wadding for shot-gun cartridges, cork-coated
fabric for balloons, as a filling for automobile tires, as a disk in the
non-refillable bottle, for the making of casks and barrels in which to
store wine, and the ground cork wood for shipping fruit, etc. in, to
prevent spoiling.
[33] See Lawrence Whitcomb’s article in _Industrial Engineering_,
September, 1910.