Cork: Its Origin and Industrial Uses Part 3

USES AND APPLICATION

Mr. H. G. Gla.s.spoole,[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 'Ph.e.l.lus' 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 Ph.e.l.lus. 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 a.s.sistance, both were saved by means of an anchor buoy. The use of this substance in a.s.sisting 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 pa.s.s 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, gla.s.s 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 gla.s.s 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. Stepha.n.u.s wrote his "Praedium Rustic.u.m," cork stoppers appear to have been very little known in France, for he states that this material was used princ.i.p.ally 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 resume 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 pa.s.s in review are worthy of description, as each of such applications has its _raison d'etre_ 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 role 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 princ.i.p.al 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 h.o.m.ogeneous. In this form cork bark const.i.tutes 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 princ.i.p.al 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 carca.s.ses of the birds that decorate their head gear. Manufacturers of dress tr.i.m.m.i.n.gs 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 b.a.l.l.s, 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 pa.s.s 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 shuttlec.o.c.ks 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 subst.i.tute 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 quant.i.ty of chips, which along with the waste derived from the collecting of the material, and with old, second-hand corks, const.i.tutes 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 coa.r.s.est 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 subst.i.tute 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 coa.r.s.est cork powder with milk of lime, and, after compression and drying, const.i.tutes, 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 pa.s.sage 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 s.p.a.ce. 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.

SUBSt.i.tUTES

Of course, no matter what the substance, a subst.i.tute is always sought for, and this has been the case with cork, but with very unfruitful results. "A primitive material used for bottle stoppers consisted of the roots of liquorice; the spongy substance of another tree called 'Spondies Lutea,' which abounds throughout the marshy regions of South America and there called 'Monbia,' was also used in the same way, as also a product called 'Myssa,' which contains some of the elements of cork.[34] Another subst.i.tute is mentioned in Henley's "Twentieth Century Receipts" as follows: Wood pulp three parts; cornstarch pith one part; gelatin one part; glycerine one part; water four parts; 20 per cent solution formic aldehyde; and still another in the "Handyman's 'Inquire Within,'" by Haslock, called "Ph.e.l.losene," a French invention consisting of powdered cork mixed with a solution of nitro-cellulose in acetone: compressed and dried. The wood of Anona pal.u.s.tris growing in the West Indies, and called the alligator's apple, is used by the negroes to stop their jugs and calabashes also, and a Mr. Brockedon invented a subst.i.tute as noted in "Knight's Cyclopedia," the core of which was cotton twisted into strands, wound with flax and the whole covered with India rubber. Cork's compet.i.tor in buoyancy, "balsa wood," is in no wise const.i.tuted to take its place, although 20 per cent lighter; as it is a fibrous growth and hygroscopic, requiring a coat of water-proofing solution before it can be used even for life-preservers; rubber, its close second, in the manufacture of stoppers is not to be compared with it, and although there have been many patent devices for sealing bottles, such as the porcelain stopper, crimped metal stoppers, etc., the cork stopper still reigns as the best of them all.

[34] _Chambers Journal._

MANUFACTURE

In describing the manner and process of converting the corkwood into the various commercial forms, no attempt will be made to give a scientific exposition of all the details, as being inconsistent with the character of this monograph, nor will any other processes be described than the ones in which the material being worked, is cork. This may exclude much of interest to the reader, but the intent of this little work is purely a corkwood exposition, and the desire to keep it so must prevail.

CORK-WOOD / / / / / / / / / VIRGIN-CORK WOOD / / / / / / /{OF / STOPPERS {STANDARD / {SIZE / / / / / / / CORK DISKS WASTE / / WASTE / / / / / / / / / / / / CORK BOARD CORK DISKS / / / / GRANULATED PACKING / MATERIAL / / CORK FLOUR SPANISH BLACK NOVELTIES