Cochineal.

The Cyclopædia
or, Universal Dictionary of Arts, Sciences, and Literature.
By Abraham Rees
(Rees's Cyclopædia)
Longman, Hurst, Rees, Orme and Brown
London, 1819 COCHINEAL, Coccus cacti, Linn.

See COCCUS cacti.

The substance known in commerce by the name of cochineal which is the most precious of all our dyeing drugs, affording the scariet crimson, and many other valuable dyes, and from which the finest carmine is generally prepared, is in the form of hemispherical thrivelled grains, about an eighth of an inch long, of a deep reddish-purple colour, and covered more or less with a white down: they are very light, and easily rubbed to powder between the fingers. The Spanish merchants distinguish at least two kinds, the best, or domesticated, called grana fina, or fine grain; and the wild, or grana sylvestra; of these, the latter is not more than half the fine of the former, and is covered with a much longer down; on which account it always bears a much lower price in the market.

The cochineal insect is a native of Mexico, and was in common use among the inhabitants as a dyeing drug when the Spaniards first came into the country; since that period its use has become more and more general, not onlyin Europe, but in various parts of Asia, and, as almost the whole of this valuable commodity is still raised in Mexico, Peru, and the adjoining Spanish settlements, it becomes every year an objet of more sedulous cultivation than before.

The best and finest cochineal, and, indeed, by far the greatest proportion of that consumed in Europe, is brought to us from Mexico. The principal districts where it is bred are Oaxaca, Tlascala, Chulula, Neuva Gallicia, and Chiapa, in New Spain, but it is in Oaxaca that the greatest quantities are produced, where the cultivation of this little insect has long given employment and been an object of commerce to the native Mexicans. According to U1loa it is likewise produced at Hambatia, Loja, and Tucuman in Peru. It has been introduced into St. Domingo, and the Brasils also.

The wild cochineal (grana sylvestra) feeds upon most of the species of cacti that are natives of Mexico, requires no particular care or attendance, and may be gathered six, times in the year, there being so many generations of this insect in a twelvemonth: the time of collecting the cochineal is just before the female produces its young, as the animal perishes immediately afterwards. The cultivated cochineal (grana fina), called also Mostique from a Mexican province of that name, is the product of slow and progressive improvement in the breed of the wild cochineal, and is found only in the gardens and plantations of Mexico, where, provided with its choicest food and sheltered from the inclemencies of the seasons, it attains nearly double its original size. This feeds only on one species of cactus, the cocheniliser or nopal, and produces only three broods in the year. Its management is simple, but requires incessant attention. At the third annual gathering of cochineal, a certain number of females are left adhering to branches of the nopal, which are then broken off and kept carefully under cover during the rainy season; when this is over, the stock of cochineal, thus preferred by each cultivator, is distributed over the whole plantation of nopals, where they soon multiply with great rapidity. In the space of two months, the first crop is gathered by detaching the insects with a blunt knife, after which they are put into bags, and dipped in hot water to kill them, and finally dried in the sun, by which they lose about two-thirds of their weight. This kind is also much more abundant in colouring matter, in which, indeed, its superiority over all other kinds consists; since, from the experiments of the French academicians, the grana sylvestra of Mexico, and the cochineal of St. Domingo, afforded colours equal in brilliancy, though not in quantity, to the meltique or grana fina. The cochineal of Vrasil also, according to Bancroft, is not inferior in quality to the fine grain of Mexico, though it contains only half the quantity of colouring matter. The proportion of coloring matter contained in equal portions of the cultivated cochineal, of the wild cochineal of Mexico, and of an inferior kind from St. Domingo, is, according to Berthollet, as eighteen, eleven, and eight.

In time of peace the cochineal of Mexico is almost exclusively sent from Vera Cruz to Cadiz, whence it is diffused all over Europe; but in time of war a contraband trade is carried on to various parts of America and the West Indies, whence this country is chiefly supplied.

The quantities of fine cochineal imported into Spain in the years 1788, 1789, and 1790, amounted to 11,000 bags, weighing 200lb. each, and making together 2,200,000lb. weight; and between the 1st of January, 1791, and the 1st of October in the same year, the importations had exceeded 2000 bags. From accurate calculations it appears that the average quantity of fine cochineal, annually consumed in Europe, amounts to about 3000 bags, or 600,000lb. weight, of which 1200 bags, or 240,000lb. may be considered as the present annual consumption of Great Britain: a greater quantity comes, indeed, into the kingdom, but the surplus is again exported to other coun-tries. The attention of the EMI. India company has been lately directed to the production of this insect, though hitherto with but partial success. It is very small, not very abundant in colouring matter, and inferior in quality to that of New Spain. It is used only for the coarsest goods, and sold from 3s. 6d. to 5s. per pound. From 8 to 10,000 lb. are annually brought to this country. See COCCUS CACTI.

Cochineal retains some traces of its original form, even in its dried state; and though Europe for a long time considered it as the seeds of an Indian plant, it is easy to select from a parcel some insects in which the round or convex back, with small transversal furrows and flat belly, are readily discovered. Its external or commercial characters differ considerably; it is distinguished by the dealers chiefly by its colour and size.
1. Time large black, or deep purple, of bright hue, is preferred to all others. Its value decreases with its size and
2. The large silver grey, though held in less estimation here, is, in general, equal to the former. It is preferred by the German buyers, to whom it is sold somewhat lower than the preceding, and from which it differs only in the less removal of that white farinaceous powder with which the insects, in their natural state, are covered.
3. The small white or silvery cochineal is held in little estimation, and sold at very inferior prices. Cochineal dust is sometimes found in the market, and also the small, or mutilatedgrains, separated by the sieve from the larger, and known by the name of Granilla. All these kinds are liable to adulteration with various subilattees, but more especially with a paste, which is sometimes managed so dexterously as to deceive the best judges, without very particular examination.

The use of cochineal was known to the Mexicans before the invasion of the Spaniards. It was the beauty of its colour, as displayed in their furniture, ornaments, and cotton cloth, which first directed the attention of their conquerors towards this precious insect. From the reports made to the Spanish ministry on this subject, orders were issued to Cortes, in the year 1523, to take measures for multiplying this valuable commodity, and considerable quantities, raised by the industry of the natives, were soon afterwards sent to Spain. Although it was for some time supposed to be the berry or seed of a vegetable; it was at length, however, "ascertained that these grains were the females of a particular species of insect, called by naturalists "Coccus cacti," and of the same genus as the "kermes" (Coccus ilicis, Linn.). See Coccus.

It is probable that alum was the only mordent used for fixing the cochineal dye for, some time after its introduction into Europe. The Mexicans also employed the same substance, as appears from the testimony of the Spanish Herrara. The colour afforded by cochineal with the aluminum mordants is crimson, and indeed, previous to the discovery of the use of tin, this seems to have been the only colour analogous to scarlet that was known. Drebbel, or, as some say, Kuster, or Keffler, a German chemist, first discovered the effect of the solution of tin in exalting the cochineal dye. He brought his secret to London about the year 1643; and the first establishment for dyeing scarlet in this country appears to have been at Bow, whence it obtained, for a long time, the name of the Bow-dye. The process was known in Holland soon after the discovery was made, and in France also, where it was practised the famous Gobelins, who received information from a Flemish painter, to whom it had been communicated by Bolter himself. For the details of this operation, and the successive improvements down to the present time, we refer our readers to the article SCARLET-Dye.

Cochineal, when thoroughly dry, if kept in a dry place, and in close packages, may be preferred many years without alteration. Hellot tried some 130 years old, and found it equal in quality to the fresh insects.

The colouring matter of cochineal may be extricated either by water or alcohol. The alcoholic solution is of a deep crimson colour, and, on evaporation, leaves a transparent residuum of a deep red, which has the appearance of a resin and which affords by distillation the products of animal substances. The aqueous solution or decoction of cochineal is of a crimson colour, bordering on purple, when viewed by transmitted lights; and this, if evaporated slowly to the continence of an extract, and then digested in alcohol, communicates to this menstruum a colour similar to the preceding spitituous solution, a residuum of the colour of wine-lees being left behind. This affords, by destructive distillation, the products of animal substances.

The aqueous decoction of cochineal, if mixed with a little sulphuric acid, assumes a red colour, inclining to yellowish, or orange hue, and a small quantity of a fine red precipitate is thrown down. Muriatic acid produces nearly the same change of colour, but occasions no precipitate. A solution of tartar, and, indeed, all acids, change the cochineal decoction to a yellowith red, and a small quantity of a pale red precipitate is slowly deposited: the supernatant liquor is yellow, but on the addition of a little alkali it becomes purple, the precipitate being at the same re-dissolved. Alum brightens the colour of the infusion and gives it a redder hue; a crimson precipitate is deposited, and the supernatant liquor retains a similar tinge. A mixture of alum and tartar produces a brighter and more lively colour, inclining to yellow; and a precipitate is thrown down, but mach paler, and less in quantity than where alum alone is used. Nitro-muriate of tin throws down a crimson sediment in considerable abundance, not a particle of colouring matter remaining in the liquor.

On adding a solution of tartar, and afterwards of tin, to the infution of cochineal, a rose-coloured precipitate is formed more quickly than in the preceding experiment. The supernatant liquor retains a tinge of yellow.

Cochineal, boiled with half its weight of tartar, affords a decoction more inclining to red, and not in deep as when boiled with water only. With the solution of tin, however, it affords a more abundant precipitate, and of a more intense colour. The extraction of the colouring particles of cochineal, therefore, is favoured by the action of tartar, though the liquor appear much paler than the simple aqueous solution.

The sulphate of iron forms a brown coloured purple, or brownish violet precipitate; and the supernatant liquor is of a dilute yellowish brown. The sulphate of zinc forms a deep purple, or deep violet; and the acetate of lead a purple-violet precipitate, less deep than the preceding; the liquor in both cases being perfectly colourless.

The sulphate of copper changes the colour of the decoction to violet, and a small sediment of the same colour slowly subsides.

Berthollet remarks a distinctive character in the colouring matter of cochineal, compared with that of madder, treated with the same re-agents. Both species of colouring matter acquire a yellow colour from acids; but if the particles of cochineal be separated by a substance, which precipitates them from the acid liquor they are dissolved in, they re-appear with their natural colour little changed, whilst those of madder retain a yellow or fawn-coloured hue. On this account the solutions of tin, which retain a great excess of acid, and are so eminently useful in exalting the colour of Cochineal, are used with little success with madder; probably as Mr. Berthollet supposes, because the combination of the oxide of tin with the colouring matter of madder, retains a larger portion of acid than it does when combined with the colouring matter of cochineal.

We have before ohserved, that the natural colour of cochineal is crimson, and that, till the discovery of the use of the solution of tin, the colour now called scarlet was un-known. The production of this colour was ascribed to the nitro-muriate of tin only, and more especially to the action of the nitrous acid of that solution, with little or no reference to the agency of the tartar, which was always employed in the operation. We are indebted to Bancroft for the correction of this error, and for a series of experiments on the action of other metallic and earthy solutions, with the colouring matter of cochineal on woollen.

From there experiments it appears, that cochineal, with the nitro-muriate of tin, or common dyers' spirits, produced a crimson only, but with the addition of tartar a good scarlet.

Cochineal, with a solution of tin in muriatic acid, dyed a beautiful crimson, and with a solution of that metal, by a mixture of tartar and muriatic acid, a beautiful scarlet.

Cochineal, with tin calcined by the long-continued action of sulphuric acid, dyed a salmon colour, and, with a recent solution of tin, a reddish salmon colour, inclining a little to the crimson. A solution of tin, in equal parts of nitric and sulphuric acids mixed; afforded a similar colour.

Tin, dissolved by the pure acid of tartar, dyed with cochineal a very beautiful scarlet, inclining a little to the aurora.

Tin very readily dissolves by pure citric acid, and even by lemon juice; and the solution, newly made, dyes with cochineal a most beautiful scarlet, inclining, like the preceding, a little to the aurora. The citric acid with tin acts, at least as efficaciously as that of tartar, in yellowing the cochineal crimson; nothing, says Dr. Bancroft, can exceed the beauty of scarlet dyed with the citrate of tin.

The solution of tin in vinegar-afforded a scarlet inclining a little to the crimson.

The phosphate of tin produced an aurora, and the fluate of tin a very good scarlet.

With other bases cochineal gave the following colours to woollen:

With nitro-muriate of platina, a red, and of gold a reddish brown.

With nitrate of silver a dull red, and with muriate of silver a lively reddish orange.

With the acetate of lead, a purple, inclining to violet; and with nitrate of lead, a delicate lively colour, between the red and Cinnamon, but inclining most to the former.

With the sulphate, nitrate, muriate, and acetate of iron, cochineal produces a dark-violet, and even a full black, when employed in sufficient quantity.

All the preparations of copper appear to debase the colouring matter of cochineal, as do those of mercury in a still greater degree; most of these, whilst they degrade the colour, seem to annihilate a portion of it.

With the nitrate and muriate of zinc, and various solutions of bismuth, cochineal produces different shades cf lilac. Cobalt and nickel also afford various shades of lilac and purple: The sulphate of manganese an orange, and the nitrate of manganese a colour resembling a madder red.

It has been before observed, that, with the aluminous mordants, cochineal affords its natural colour, or crimson. Dr. Bancroft has also examined the effects of other earthy solutions.

Lime-water, with cochineal, dyes a purple, which took but slowly, and required long boiling.

Sulphate of lime a full dark red, and nitrate of lime a lively red, approaching to scarlet, and muriate of lime a purple.

The solutions of barytes and of magnesia, afforded various shades of lilac, and even the solution of silex in caustic alkali, precipitated by the addition of an acid, affords a full rich pleasing purple, which proved sufficiently durable.

The foregoing experiments repeated on silk gave less advantageons results. Cochineal, indeed, with the aluminous basis, dyes the crimson colour as well and as durably on silk as on wool. The modes of producing this are well known, and will be treated of hereafter, but in general, with the other earthy and metallic bases, cochineal produced similar but much paler colours than on wool.

The little disposition manifelted by the colouring matter of cochineal to unite with cotton, and the celebrated experiment of Mr. Dufay to illustrate this, are well known. He caused a piece of cloth to be manufactured with a woollen web and cotton woof, and having subjected it to the ordinary process of dyeing scarlet, found that the wool had taken a most beautiful scarlet, whilst the cotton remained perfectly white. Subsequent experiments have shown that this effect arises not from the total want of affinity between the colouring particles of cochineal united to tin, and the fibres of cotton, but from a striking and powerful difference in the force with which the colouring matter is attracted by the two substances. When cotton alone is subjected to the same process, it takes a scarlet colour more slowly indeed, and paler than that imbibed by woollen, yet sufficient to prove its disposition to such union, when not ccounteracted by more powerful affinities. When cotton and wool, however, are jointly subjected to the operation of scarlet dyeing, the latter, by its strong attraction, draws, and exclusively appropriates to itself, all the colouring matter in the vessel before the cotton has had time to engage any part of it. It is owing to this weaker attraction between the fibres of cotton and the scarlet dye, that this latter is so much less permanent on cotton than on wool; and it is also from this want of sufficient attraction that the cochineal colour is found to take most beneficially on cotton, when the basis has first been applied separately.

Cochineal is sometimes used by calico printers in topical dyeing, but more frequently in the preparation of those colours for the pencil, which are described under the article Colour making.

The mordants used for cochineal are those employed with Madder. The acetate of iron, or iron liquor for black, diluted solutions for various shades of purple or lilac, and mixtures of the acetates of iron and alumine for chocolates, blooms, &c. &c.

With the common aluminous mordant, printed and rinsed off the same as for madder red, cochineal affords a bright and beautiful crimson. It is, however, much less fixed than madder, and cannot support repeated washing and exposure. It is applied chiefly on line cloth and delicate muslins, when the solidity of the colour is oftentimes an object of less consideration than its beauty. An addition of one-tenth, or fifteenth, of galls to the cochineal, gives it greater stabipity, but this permanency is gained at the expence of its lustre. The fine crimson disappears, and the colour approaches more to the red or middle hue. An advantage attending the use of cochineal, is its little effect on the white or unprinted part of the cloth, which acquires no stain in the dyeing, but what is completely removed by simple washing, or, in some particular cases, by very gentle branning. From two to three ounces of cochineal, according to the fulness of the pattern, are sufficient for a piece of light ground. The pale delicate crimson grounds, with white objeats, require from four to five ounces. It must be finely ground, and inclosed in a linen or cotton bag, suspended in the dye-copper, from whence it can be occasionally taken and squeezed or wrung, for the more complete extraction of the colour.

In dyeing with cochineal, the value of this drug renders every precaution for economizing its use indispensably necessary, and a considerable saving is made by diminishing as much as possible the quantity of the dye liquor. It is well known, that colouring matter of any kind, held in solution in the dye-copper, can only be exhausted to a certain degree, even by fresh and undyed goods; there is a certain point at which the affinity, of the water for colouring matter becomes equal to that of the strongest mordants, and all that is thus retained may be considered as totally lost, except when fresh portions of colouring matter are added to the already exhausted liquor, and the operation of dyeing again renewed, in which case the loss is inversely as the number of successive operations performed in the same liquor. In dyeing with cochineal, therefore, no more water should be used than is barely sufficient to cover the goods when pressed down close into the copper, with a stick as they come over the winch, and three successive dyeings, at least, should he passed through the same liquor before it is let off, and the copper replenished with fresh water. Long continued heat has a tendency to injure the cochineal crimson, and incline it too much to the purple hue; each dyeing, therefore, should be withdrawn shortly after it has attained the boiling point. The first sets may be boiled three minutes; the second, one; the third set may be kept five or six minutes at the boil, if it consists of darker colours, such as chocolates, dark purples, &c.; but if crimsous, the colour, without boiling, will incline very much to the purple hue, and be much inferior to the first, and even to the second sets. On this account it is proper, when the work will admit of it, to dye the pale crimson grounds first, follow after with the stronger light grounds, and, lastly, with the darker colours above-mentioned.

The use of tin vessels in dyeing scarlet or woollen, (where the acid solutions used in that operation render them indispensably necessary) has induced many calico printers to employ them in dyeing cotton, where no acid solution is present, and where the good effects of tin may be supposed not to apply. It is certain, however, that the hue of the pale and delicate crimson grounds produced in a tin vessel is much superior to that produced in copper, and the cause of this difference is satisfactorily explained by the experiments of Mr. Thomson. From these experiments, which will be more fully detailed in another part of this work, it appears that the colouring matter of cochineal possesses very distinct acid properties.

Turnings of pure soft iron digested in a strong decoction of cochineal were dissolved, with disengagement of hydrogen gas. The solution, at first purple, gradually acquired a more intense colour, approaching to black. Exposed to the atmosphere, it gradually absorbed oxigen, and let fall a black precipitate. It communicated to cloth a dark grey or purple colour, which was not removed by washing. With tin the decoction of cochineal formed a beautiful crimson solutien, and, with copper, a dull crimson inclining to purple; both these solutions imparted their colour to cloth, which rinsing did not remove. Hence it appears that the difference in the colours, produced in a tin and in a copper vessel, arise from the action of the colouring matter on the substance of the vessel itself.

The colouring matter of cochineal also acts powerfully on the earths and metallic oxides, or on its own combinations with them or cloth. A piece of calico impregnated with a weak aluminous mordant, and dyed in a strong decoction of cochineal, takes at first a dye which is, however; speedily removed, and the mordant itself soon after carried off the cloth. The same takes place with the dilute solutions of iron. In dyeing with cochineal, therefore, in the way prescribed above, same care is necessary in the management of those goods, on which weak as well as strong mordants are applied, left with the treatment necessary to bring up the latter to their proper strength and fulness, the former be totally deftroyed.

The beautiful pigment carmine, used chiefly in miniature and water-colour painting, and sometimes under the name of rouge, to freshen the cheeks of pallid or faded beauty, is also a preparation of cochineal. It is a light, lost, velvety powder, of a most rich and magnificent scarlet, inclining a little to crimson. It was formerly made from kermes, whence its present name is derived.

The preparation of carmine, notwithstanding the numerous processes detailed in various works, still remains one of those secrets which are confined to the laboratories of a few. Its constitution, indeed, and the general nature of the process for obtaining it, are well known; but excellence in colours of this kind often depending on particular hue, arising from minute but important conditions in the preparation, approved processes are guarded with religious care, confined to the workshops that gave them birth, in which myttery and prejudice are despotic.

We subjoin the following formula without vouching for its merit; it is, however, at least, as good as any other published.

Pour two quarts of fine clear river water into a clean copper pan, and, when boiling, add two ounces of the best grain cochineal, finely ground and sifted. Boil six minutes, stirring carefully the whole time. Add sixty grains of fine Roman alum in powder, and boil three minutes longer, after which withdraw it from the fire and let it cool a little. Decant off the liquor carefully from the grounds, and drain through a silksieve fine enough to retain the undissolved grains. Pour it into well-glazed porcelain dishes and suffer it to remain undisturbed three or four days, after which time again decant the red liquor into other dishes from off the sediment which his formed, and which, dried in the shade and free from dust, forms the fine carmine. Another deposition takes place at the end of a few days from the decanted liquor, which forms a good carmine of second quality, and there still remains colouring matter sufficient in the remaining liquor to afford a rich lake.

The following process, not very different from the former, has been recommended; and, if carefully pursued, will yield a pigment greatly superior to the carmine that is generally met with. Into a fourteen-gallon boiler of well-tinned copper put ten gallons of distilled or very clear rain water (spring water will not answer the purpose). When the water boils, sprinkle in, by degrees, a pound of fine cochiaeal, previously ground in a clean stone mortar to a moderately fine powder; keep up a gentle ebullition for about half an hour, and then add three ounces and a half of crystallized carbonat of soda; in a minute or two afterwards draw the fire, and then add to the liquor an ounce and a half of Roman alum, very finely pulverized; stir the mass with a clean stick till the alum is dissolved, then leave it to settle for 25 minutes, and afterwards draw off the clear liquor with a glass syphon, and separate the rest of the fluid from the sediment by straining it through a close linen cloth. Replace the clear liquor in the boiler, and stir in the whites of two eggs, previously well beaten with a quart of warm water; then light the fire again and heat the liquor till it begins to boil, at which time the albumen of the eggs will coagulate and combine with the earth of the alum and the finest part of the coloaring matter; this sediment is the carmine, and being separated by filtration, and well washed on the filter with distilled water, it is to be spread very thin on an earthen plate, and slowly dried in a stove; after which it is fit for use. The finest part of the colouring matter of the cochineal being thus separated, the residue may be employed in the preparation of red lake in the following manner: Add two, pounds of pearlash to the red liquor from which the carmine was precipitated, and return it into the boiler together with the dregs of the cochineal, and boil the whole gently for about half an hour; then draw the fire, and, after the sediment has subsided, drain off all the clear liquor into clean earthenware vessels. Then pour upon the sediment a second alkaline ley, prepared by dissolving a pound of pearlash in two gallons of water, and boil this also upon the dregs for half an hour; by which process the whole of the colouring matter will be exhausted. Separate by filtration the liquor from the dregs, and return both the alkaline-solutions into the copper. When this bath is as hot as the hand can bear, add, by degrees, three pound, of finely pulverized Roman alum, observing not to add a second portion, till the eftervescence from the first has entirely subsided. When the whole of the alum has been put in, raise the fire till the liquor simmers, and continue it at this temperature for about five minutes, at which time, if a little is taken out and put into a wine glass, it will be found to consist of a coloured sediment diffused through a clear liquor; after-landing quiet a while the greater part of the clear supernatant liquor may be poured off, and the residue being placed on the filter, will there deposit the coloured lake, which, after being accurately washed with clear rain water, may be covered with a cloth, and allowed to remain for a few days till it is half dry: it is now to be separated from the filter, to be made up in small lumps, and placed in a stove to dry. By this management a pound of good Mexican cochineal will afford one ounce and a half of carmine, and about a pound and a quarter of red lake.

If the colour is required to incline somewhat towards scarlet, this may be effected by grinding along with the cochineal from a quarter to half an ounce of the best annotto.

The French add to the infusion of cochineal a small proportion of autour, a bark containing yellow colouring matter, and also of chouan, a greenish yellow feed; both from the Levant. They serve to brighten the hue of the carmine, and incline it more to scarlet. Carmine has a slight taste easily recognized as that of cochineal. It is sparingly soluble in water, to which it communicates its own colour. Mixed up with water it works stiffly with the pencil and affords a poor colour. Ammonia dissolves it instantly, forming with it a deep transparent crimson-coloured solution, inclining much to purple. This is the test of its purity, for the inferior or adulterated carmine is insoluble, and falls to the bottom. The painters generally grind or mix it with ammonia for the deep rich reds, and its solutions in that alkali afford most beautiful pink or role colours.

Carmine appears to be a lake in which the colouring principle predominates very much over the basis; hence its solubility in ammonia, which the true or perfect lakes do not possess.