Kappale teoksesta:
The Library of Entertaining Knowledge.
A Description And History of Vegetable Substances, used in The Arts, and in Domestic Economy.
Timber Trees: Fruits.
Illustrated with wood engravings.
Second edition.
London: Charles Knight, Pall Mall East.
Longlamn, Rees, Orme, Brown, & Green, Paternoster-Row; Oliver & Boyd, Edinburgh; Robertson & Atkinson, Glasgow; Wakeman, Dublin; Willmer, Liverpool; Baines & Co., Leeds; And G. & C. Carvill, New York.
MDCCCXXX.
London: Printed by William Clowes. Samford-street.
Vegetable Substances, Part I. Timber Trees. Chapter I.
s. 1-19
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THE OAK.
In point of strength, durability, and general application, Oak claims the precedence of all timber; and to England, which has risen to the highest rank among the nations, mainly through her commerce and her marine, the oak, " the father of ships," as it has been called, is inferior in value only to her religion, her liberty, and the spirit and industry of her people.
Of the Oak (called Quercus, in Latin), there are fourteen species described by Linnaeus. During the last fifty years, so much attention has been paid to this important tree by travellers distinguished for their researches in natural history, that a surprising addition has been made to the number of known
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species. Professor Martyn, in his edition of Miller's Gardener's Dictionary, enumerates twenty-six; Willdenow, who wrote in 1805, describes seventy-six; and Persoon, another eminent naturalist of the same date, enumerates eighty-two. At present we have more than a hundred and forty species described by different writers; and of these more than one half belong to America. Twenty-six species were discovered in North America by two indefatigable naturalists, father and son, named Michaux; and Humboldt and Bonpland have mentioned twenty-four others, which they found during the course of their travels in South America. Of the various species of oak, some may be classed with shrubs, others with the most majestic trees of the forest; some are evergreens, and others are deciduous, or lose their leaves during the winter. The species from which the best timber is derived, which is by far the most abundant in Britain, and a native of it, is the COMMON OAK (Quercus robur).
The cut opposite exhibits the leaf, flower, and fruit (the type) of this tree. We shall introduce the same mode of illustration in other instances.
The oak timber imported from America is much inferior to that of the common oak of England: the oak from the central parts of continental Europe is also inferior, especially in compactness and resistance of cleavage. The knotty oak of England, the "unwedgeable and gnarled oak," as Shakspeare called it, —and in these two words described its leading properties better than all the botanists, — when cut down at a proper age (from fifty to seventy years), is really the best timber that is known. Some timber is harder, some more difficult to rend, and some less capable of being broken across; but none contains all the three qualities in so great and so equal proportions; and thus, for at once supporting a weight, resisting a strain, and not splintering by a
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cannon shot, the timber of the oak is superior to every other. Excepting the sap wood, the part nearest the bark, which is not properly matured, it is very durable, whether in air, in earth, or in water; and it is said that no insects in the island will eat -into the heart of oak, as they do, sooner or later, into most of the domestic and many of the foreign kinds of timber.
Important as the.oak is now in the arts, there was a period in the history of Britain when it was valued principally for its acorns. It is not recorded that acorns were ever used as human food in this country, though they were so used, and are still said to be, by the poorer peasants in the south of Europe. Cervantes, in his romance of Don Quixote, not only sets them before the goatherds as a dainty, but picks out the choicest as a dessert for the Countess herself. The oaks with edible acorns are not, however, of the same species as the English oak. The Italian oak, which
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Virgil represents as the monarch of the forest, and of the elevation of whose top, the stedfastness of whose roots, and of whose triumph in its greenness over the lapse of ages, he gives a splendid description in the second book of his Georgics, bore fruit which was used as food. The Quercus ilex (the evergreen oak), which is still common in Spain, in Italy, in Greece, in Syria, in the south of France, and on the shores of the Mediterranean, bears a fruit, which, in its agreeable flavour, resembles nuts. It is a slow-growing tree, and is always found single, and not in clumps. There is another evergreen oak, Quercus ballota, very common in Spain and Barbary, of which the acorns are most abundant and nutritive. During the late war in Spain, the French armies were fortunate in finding subsistence upon the ballota acorns, in the woods of Salamanca. We are often startled by the assertions of ancient writers, that the acorn, in the early periods of society, formed the principal food of mankind. Much of our surprise would have ceased had we distinguished between the common acorn, and that of the Ilex, Ballots, and Esculus oaks. Some of the classic authors speak of the fatness of the primitive inhabitants of Greece and southern Europe, who, living in the forests which were planted by the hand of Nature, were supported almost wholly upon the fruit of the oak. The Grecian poets and historians called these people balanophagi (eaters of acorns); but then the Greek word balanos, which the Romans translated glans (acorn), applied also to such fruits as dates, nuts, beech-mast, and olives. These all contain large quantities of oil, which renders them particularly nutritive.
Whether the custom existed among the ancient Britons, or (as is more probable) was imported by the Saxons who came from the thick oak-forests of Germany, it is certain that, during the time when
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they held sway in this country, the fattening of hogs upon acorns in the forests was accounted so important a branch of domestic economy, that, at about the close of the seventh century, King Ina enacted the panage laws for its regulation. The fruit of the oak then formed gifts to kings, and part of the dowries of queens. So very important was it, indeed, that the failure of the acorn crop is recorded as one of the principal causes of famine. One of the most vexatious acts of William the Conqueror, in his passion for converting the whole of the forests into hunting-grounds, was that of restricting the people from fattening their hogs; and this restriction was one of the grievances which King John was called upon to redress at the triumph of Runnemede, where his assembled subjects compelled him to sign Magna Charta. It is to be observed that swine's flesh was the principal food of most nations in the earlier stages of civilization; and this is to be attributed to the extreme rapidity with which the hog species multiply.
Up to a recent period, large droves of hogs were fattened upon the acorns of the New Forest, in Hampshire, under the guidance of swineherds, who collected the herds together every night by the sound of a horn. At the present time, the hogs of Estremadura are principally fed upon the acorns of the Ballota oak; and to this cause is assigned the great delicacy of their flesh.
The history of the importance of the oak as timber nearly keeps pace with that .of. ship-building; and there is little doubt that, from the time of Alfred, who first gave England a navy capable of contending with her enemies upon the sea, to that of Nelson (about nine hundred years afterwards), in whom nautical skill appears to have been raised to the greatest possible height, the oak was the principal and essential material in ship-building. It has been stated that
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the inferiority of some of our more recently built ships, and the ravages which the dry rot is making among them, have arisen from the substitution of foreign oak for that of native growth. * Some of the most eminent botanists and planters deny the accuracy of this statement; and we therefore omit the extract which we gave in the first edition of this work. A writer in a recent number of the Quarterly Review has ascribed this evil to the substitution of a foreign species of oak, in our own plantations, instead of continuing the true native tree*. In the same way, the real Scotch fir has been gradually superseded by a very inferior species, bearing the same name. It is highly probable, however, that the cultivation of some species, both of oak and of other trees, in richer soils and less exposed situations than are favourable to their greatest perfection, may produce this degeneracy. The following extract from the work of a distinguished planter, Sir Henry Steuart, offers some interesting illustrations of this circumstance: -
"I The common oak in Italy and Spain, where it grows faster than in Britain, is ascertained to be of shorter duration in those countries. In the same way, the oak in the highland mountains of Scotland or Wales is of a much harder and closer grain, and therefore more durable, than what is found in England; though on such mountains it seldom rises to the fifth part, or less, of the English tree. Every carpenter in Scotland knows the extraordinary difference between the durability of highland oak, and oak usually imported from England, for the spokes of wheels. Every extensive timber dealer is aware of the superior hardness of oak raised in Cumberland and Yorkshire over that of Monmouthshire and Herefordshire; and such a dealer, in selecting trees in the same woods in any district, will always give the preference to oak of slow growth, and found on cold and clayey soils,
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and to ash on rocky cliffs; which he knows to be the soils and climates natural to both. * Planters Guide, p. 476. If he take a cubic foot of park oak and another of forest oak, and weigh the one against the other (or if he do the like with ash or elm of the same descriptions), the latter will uniformly turn out the heavier of the two*."
When the oak stands alone, it is a spreading rather than an elevated tree; in that situation the timber is said to be more compact and firm, and the crooked arms of the trees are better adapted for ship-building than when the trees are close together. In thickly planted groups, the oak will reach an elevation of eighty or a hundred feet before it begins to decay; and in some of the choicer trees, forty, fifty, or even sixty feet may be found without a single lateral, branch, and of such diameter that, even at the smaller extremity, they will square to eighteen inches or two feet. These are as well adapted for beams and planking as the others are for crooked timbers; and, therefore, in order to secure a proper supply, not only for maritime, but for domestic purposes, it is desirable to have them in both situations.
The trunk of the detached oak acquires by far the greater diameter; some of the old hollow trees, most of which are of this description, having a diameter of as much as sixteen feet in the cavity, and still a shell of timber on the outside, sufficiently vigorous for producing leaves, and even acorns. The age to which the oak can continue to vegetate, even after the core has decayed, has not been fully ascertained. But, in favourable situations, it must be very considerable. In the New Forest, Evelyn counted, in the sections of some trees, three hundred or four hundred concentric rings or layers of wood, each of which must have recorded a year's growth. The same celebrated planter mentions oaks in Donnington Park, near Newbury, once the residence of Chaucer, which could
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not have arrived at the size which they possessed in a less period than about three hundred years; and though he does not say upon what evidence the opinion is grounded, Gilpin notices, in his Forest Scenery, "a few venerable oaks in the New Forest, that chronicle upon their furrowed trunks ages before the Conquest."
Some out of the number of ancient oaks that are celebrated, it may not be uninteresting to mention: —One of the three in Donnington Park, the King's oak, was fifty feet high before a bough or even a knot appeared, and the base of it squared five feet entirely solid; the Queen's oak was straight as a line for forty feet, then divided into two immense arms, and the base of it squared to four feet; and Chaucer's Oak, said to have been planted by the poet, though inferior to the royal ones, was still a most stately tree. The Framlingham oak (Suffolk), used in the construction of the Royal Sovereign, was four feet nine inches square, and yielded four square beams, each forty-four feet in length. An oak felled at Withy Park, Shropshire, in 1697, was nine feet in diameter, without the bark; there were twenty-eight tons of timber in the body alone; and the spread of the top, from bough to bough, was one hundred and forty-four feet. In Holt Forest, Hampshire, there was an oak, which, at seven feet from the ground, was thirty-four feet in circumference in 1759; and twenty years after, the circumference had not increased half an inch. Dr. Plott mentions an oak at Norbury, which was of the enormous circumference of forty-five feet; and when it was felled, and lying flat upon the ground, two horsemen, one on each side of the trunk, were concealed from each other. The same author mentions an oak at Keicot, under the shade of which four thousand three hundred and seventy-four men had sufficient room to stand. The Boddington oak, in the vale of Gloucester, was fifty-four feet in
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circumference at the base. The larger arms and branches were gone in 1783; and the hollow cavity was sixteen feet in its largest diameter, with the top formed into a regular dome; while the young twigs on the decayed top had small leaves about the size of those of the hawthorn, and an abundant crop of acorns. The hollow had a door and one window; and little labour might have converted the tree into a commodious and rather a spacious room. The Fairlop oak, in Essex, though inferior in dimensions to the last mentioned, was a tree of immense size, -being between six and seven feet in diameter, at three feet from the ground. Damory's oak in Dorsetshire was the largest oak of which mention is made. Its circumference was sixty-eight feet; and the cavity of it, which was sixteen feet long and twenty feet high, was, about the time of the Commonwealth, used by an old man for the entertainment of travellers, as an ale-house. The dreadful storm in the third year of last century shattered this majestic tree; and in 1755 the last vestiges of it were sold as firewood. An immense oak was dug out of Hatfield bog in Yorkshire. It was a hundred and twenty feet in length, twelve in diameter at the base, ten in the middle, and six at the smaller end where broken off.
Some oaks have been as celebrated for being the records of historical events, as others have been for their magnitude, although a part of the celebrity may no doubt be fabulous. Not a hundred years ago, the oak in the New Forest, against which the arrow of Sir William Tyrrel glanced before it killed William Rufus, is said to have been standing, though in such a state of decay, that Lord Delaware erected a monument to indicate the spot. The Royal Oak at Boscobel, in which Charles the Second concealed himself after the defeat at Worcester, has disappeared; and though several trees were raised from its acorns, the race seems now to be lost to vege‑
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table history. An oak of still more venerable pretensions now stands, or lately stood, at Torwood Wood, in Stirlingshire, under the shadow of which the Scottish patriot Wallace is reported to have convened his followers, and impressed upon them, not only the necessity of delivering their country from the thraldom of Edward, but their power of doing it, if they were so determined. Gilpin mentions one, more ancient even than this—Alfred's oak at Oxford, which was a sapling when that great monarch founded the University. This cannot, of course, be implicitly credited; but still the very mention of such things proves, that the oak can reach an age several times exceeding that of the longest lived of the human race.
Since oak was so much in demand, it has become an object of great attention to planters; and the plants are carefully reared by nurserymen from the acorns. If the saplings are to be of considerable size when planted out in their permanent situations, they are several times transplanted in the nursery. The deformed ones are cut down to the ground, and then a young, vigorous, straight shoot is made, instead of that which was deformed. Some of those who have paid considerable attention to the subject are, however, of opinion, that although transplanting probably accelerates the growth a little, the advantage thereby gained is more than compensated by the deterioration of the timber, which is neither so strong, nor so durable, as that sown by the hand of Nature, or where it is to be allowed to remain without transplanting.
* Planters Guide, p. 478. In the "Notes and Illustrations" to Sir Henry Steuares interesting work*, may be found some important observations on the best method of raising oak timber for naval purposes. Our limits preclude little more than a reference to this subject; but the following principles may be stated as the result of
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this writer's observations upon the effect of culture: - "If trees be in a soil and climate worse than those that are natural to them, then culture will be of some advantage, as the extra increase of wood will be of a quality not inferior to what in its natural state it would obtain; or, in other words, it will correspond with that degree of quality and quantity of timber which the nature of the species admits of being obtained; but culture, in this case, must be applied with cautious discrimination, and a sound judgment. On the other hand, if trees be in a better soil and climate than are natural to them, and, at the same time, that the annual increase of wood be will promoted by culture, it be a decided disadvantage, and deteriorate the wood. In the same way, if trees be in their natural state, the annual increase of timber, obtained by culture, will injure its quality, in a degree corresponding with the increased quantity."
Of the various European oaks, the Quercus pedunculata is the most esteemed on the Continent. It is a magnificent tree, considerably taller than our native oak. In the forests of Fontainebleau and of Compiègne there are at this day many trees of this species, the trunks of which measure from thirty to thirty-six feet in circumference at the base, and rise to the height of forty feet without a single branch. Beautiful as this species is, it produces, however, timber very inferior to our Quercus robur. It is probable that the species which is indifferently designated by French botanists Quercus robur, and Quercus sessiliflora, is a species entirely different from our real English oak; for the wood of the Quercus pedunculata is described by these writers as harder and more compact than that of the robur or sessiliflora. The Quercus alba of North America very much resembles the Quercus pedunculata. It is found in all the countries of the United States, from
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Florida up to Canada. It is the species chiefly used in ship-building, and for houses; and casks for liquors are principally made of it, as those of the red oak will only contain dry goods. Considerable quantities of this timber are imported into England. Parkinson relates that the Indians extracted an oil from the acorns of this species, with which they prepared their food. The quercitron (Quercus tinctoria) is, after the white oak, commonly preferred for the construction of houses in the United States. The bark of this species affords a yellow dye, which is a considerable article of commerce; it is used for dyeing silk and wool. The quercitron is employed by the Americans in tanning leather, chiefly on account of its abundance; but the yellow colour which it imparts to skins is considered a defect, and is generally removed by a subsequent chemical process. In the United States, the bark of almost every sort of tree is used for tanning; the abundance with which it is procured rendering selection less necessary. In England, oak bark is almost exclusively applied to this purpose, as it contains the largest- quantity of tannin of any known substance. The leaves of some trees may be so applied. The Chinese use the coarser leaves of the tea-tree in the preparation of leather.
A fine oak is one of the most picturesque of trees. It conveys to the mind associations of strength and duration, which are very impressive. The oak stands up against the blast, and does not take, like other trees, a twisted form from the action of the winds. Except the cedar of Lebanon, no tree is so remarkable for the stoutness of its limbs; they do not exactly spring from the trunk, but divide from it; and thus it is sometimes difficult to know which is stem and which is branch. The twisted branches of the oak, too, add greatly to its beauty; and the hori-
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zontal direction of its boughs, spreading over a large surface, completes the idea of its sovereignty over all the trees of the forest. Even a decayed oak -
"- and dead,
Still clad with reliques of its trophies old,
Lifting to heaven its aged, hoary head,
Whose foot on earth hash got but feeble hold-"
—even such a tree as Spenser has thus described is strikingly beautiful: decay in this case looks pleasing. To such an oak Lucan compared Pompey in his declining state.
The CORK OAK (Quercus suber) is not so large a tree as the common oak. There are several varieties: a broad leaved and a narrow leaved, which are evergreens; besides other varieties which shed their leaves. The broad-leaved evergreen is, however, the most common, and it is the one from which the cork of commerce is chiefly obtained. It is mentioned by Theophrastus, Pliny, and some other ancient naturalists, as being well known in the days of the Greeks and Romans,—the latter of whom used it for a variety of purposes, and among the rest for the stopping of bottles. They used it for floats to their nets and fishing tackle; for buoys to their anchors; and when Camillus was sent to the Capitol, through the Tiber, during the siege by the Gauls, he had a life-preserver of cork under his dress.
The Cork Oak is indigenous, or at least abundant, in Portugal, Spain, part of the south of France, and Italy; on the opposite coast of the Mediterranean, and the Levant. Spain and Portugal supply the greater Portion of the cork which is consumed in Europe. The cork is the bark which the tree pushes outwards, as is common to all trees: but here the outer bark is of larger quantity, and is more speedily renewed. When removed, there is a liber,
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or inner bark, below it, and from this the cork is reproduced in the course of a few years,—while the tree is said to live longer, and grow more vigorously, than if the cork were not removed. The first time that the cork is taken off, is when the tree is about fifteen years old. That crop is thin, hard, full of fissures, and consequently of little value; and the second, which is removed about ten years after, is also of an inferior quality. After this, the operation is repeated once in eight or ten years, the produce being greater in quantity, and superior in quality, each successive time. According to Duhamel, a corktree thus barked will live a hundred and fifty years. The months of July and August are those which are chosen for removing the cork. The bark .is cleft
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longitudinally, at certain intervals, down to the crown of the root, with an axe, of which the handle terminates in a wedge; and a circular incision is then made from each extremity of the longitudinal cuts. The bark is then beaten, to detach it from the liber; and it is lifted up by introducing the wedged handle, taking care to leave sufficient of the inner laminae upon the wood, without which precaution the tree would. certainly die. The bark being thus removed, it is divided into convenient lengths; and it is then
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flattened, and slightly charred, to contract the pores. This substance is the rough cork of commerce; and it is thus fit to be cut into floats, stoppers, shoe-soles, and other articles of domestic use, by the manufacturer. The cork of the best quality is firm, elastic, and of a slightly red colour. Two thousand five hundred tons of cork were imported into the United Kingdom in 1827. Cork burned in vessels of a particular construction gives the substance called Spanish black.
The Oak from which the nut-galls of commerce are procured (Quercus infectoria) is minutely described by M. Olivier, in his Travels. The species is very common in Asia-Minor; but, till the time of this traveller, Europeans had very little information on the subject, although the galls were a considerable article of commerce. It is a shrub, seldom exceeding six feet in height; and it has not only been accurately described by M. Olivier, but was introduced by him into France, where it is cultivated as a garden shrub, and grows well in the open air.
The gall is a morbid excrescence produced by the puncture of a winged insect, to which Olivier has given the name of Diplolepis Gallae Tinctoriae. This excrescence is of a globular form, with an unequal and tuberculous surface. It is developed on the young shoots of the tree, and contains within it the eggs which the insect has deposited. The best galls are gathered before the transformation of the insect, because in that state they are heavier, and contain more of the tannin principle. When the insect has left them, they are pierced from the interior to the surface. The best galls come from Aleppo. The substance of which they are composed is peculiarly astringent; of which, according to Sir Humphry Davy, five hundred parts contain a hundred and eighty parts of soluble matter, principally formed of tannin and gallic acid. One
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hundred -and seventy-four tons of galls were imported into the United Kingdom in 1827.
The instinct by which certain insects choose for the nests of their future offspring the substance of various vegetable bodies, is one of the most curious provisions in the economy of Nature. After having pierced those bodies, they deposit their eggs, which, being hatched, produce larvae, that are more or less fatal to the vegetable substance to which they are attached. In the volume of this series, entitled "Insect Architecture," will be found a minute account of the mode in which this genus of insects (Cynips) conduct their remarkable operations. They are provided with a needle in a sheath, which has most surprising powers of extension, derived from the peculiar construction of the whole body of the insect, so much so that the needle can be extended to double the length of the animal itself; and with this instrument, it forms a nest for its offspring, while the young, in the same manner, pierce their way out of the vegetable shell which has been their protection. In this way is the gall produced. The oak-apple is an excrescence of the same nature, though effected by a different species of insect. There are various insects possessing the instinct thus to deposit their eggs, that are furnished with an apparatus of the curious construction above described, necessary for puncturing the branch, as is done by the parent; and for piercing a way out of the gall, as is done by the insect produced, after it has passed its larva state. Each species of insect chooses not only the particular vegetable, but the part of that vegetable which is best adapted for the reception of its larvae; and in this way the same plant, for instance the oak, sometimes receives the nests of twenty different species of insects. A gall sometimes contains a single larva, sometimes many, and it is thus either
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called simple or compound. A late agreeable writer on Natural History has given us some sensible observations on the subject of galls, and the instincts of the little creatures that produce them: -
"The insect that wounds the leaf of the oak, and occasions the formation of the gall-nut, and those which are likewise the cause of the apple rising on the sprays of the same tree, and those flower-like leaves on the buds, have performed very different operations, either by the instrument that inflicted the wound, or by the injection of some fluid to influence the action of the parts. That extraordinary hairy. excrescence on the wild rose, likewise the result of the wounds of an insect (Cynips rosae), resembles no other nidus required for such creatures that we know off; and the red spines on the leaf of the maple are different again from others. It is useless to inquire into causes of which we probably can obtain no certain results; but, judging by the effects produced by different agents, we must conclude, that, as particular birds require and fabricate from age to age very different receptacles for their young, and make choice of dissimilar materials, though each species has the same instruments to effect it, where, generally speaking, no sufficient reason for such variety of forms and textures is obvious; so is it fitting that insects should be furnished with a variety of powers and means to accomplish their requirements, having wants more urgent, their nests being at times to be so constructed as to resist the influence of seasons, to contain the young for much longer periods, even occasionally to furnish a supply of food, or be a storehouse to afford it when wanted by the infant brood*."* Journal of a Naturalist, page 109.
In Spain, in the southern provinces of France, and along the Mediterranean coasts of Africa, there is
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found in great plenty a small species of oak, called the Kermes (Quercus coccifera), which is remarkable for nourishing large quantities of a small insect (Coccus ilicis), which, being gathered, forms an article of commerce called kermes. The declivities of the Sierra Morena are covered with the kermes oak; and many of the inhabitants of the province of Murcia have no other mode of living than gathering the kermes. Latreille has united this insect to the cochineal family, which it resembles, not only in its form, but in producing a scarlet dye. Till the discovery of the cochineal insect upon certain species of the Cactus in South America, the kermes was the only substance used in dyeing scarlet, from the period of the disuse and loss of the Murex and Buccinum,—the shell-fish that produced the Tyrian purple of the Romans. The people of Barbary employ the kermes for dyeing the scarlet caps used by the natives in the Levant, and they prefer that of Spain to their own produce. In England, and in other countries where manufactures are extensively carried on, the cochineal has almost entirely superseded the use of the insect scarlet dye of Europe.
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