Part 117

_Prop., Purific., &c._ Copaiba, though usually called a 'balsam,' is not correctly so named, as it contains no benzoic or cinnamic acid. It is correctly described in the B. P. as an 'oleo-resin.' Considerable variation exists in the colour, odour, consistence, and transparency, as well as in the proportion of oil and resin yielded by different samples, scarcely any two of which exactly agree. The sp. gr. varies from ·950 to ·996. Brazilian copaiba is thin, clear, and pale; whilst the West Indian variety is thick, golden yellow, less transparent, and has a less agreeable and somewhat terebinthinate smell. Some varieties are opaque, and continue so unless filtered. This is often a most troublesome operation. The opacity generally arises from the presence of water, which it retains with great tenacity. The following is the plan we have found to answer on the large scale:--Place the casks upon their ends in a warm situation, and leave them so for 10 days or a fortnight, or longer, if convenient. They may then be tapped a little above the bottom, when the contents of some of them will generally be found quite transparent, and may be drawn off and vatted, care being taken to avoid shaking up the bottom. The copaiva that remains foul must be filtered through one or more long Canton flannel bags, sunk in the bottom of a tin cistern, placed over a suitable receiver, in a similar way to that adopted for oils; a few pounds of coarsely powdered charcoal being mixed up with the first 5 or 6 gallons thrown in. This will rapidly fill up the pores of the bag, and make the balsam soon flow clear and pale. The "bottoms" of the casks, containing the water and impurities, may be poured into a large can or jar, and allowed to settle for a few days, when the copaiba may be poured off the top and filtered. A sudden change of temperature will frequently turn a transparent sample of this article opaque or milky; it is not, therefore, deemed fit to send out by the wholesale trade, unless it stands this test. To ascertain this point a common practice is to fill a small bottle with the copaiba, and to leave it out of doors all night in an exposed situation.

_Pur., Tests, &c._ This substance is frequently adulterated; indeed, fully one half that sold for copaiba does not contain 10% of the genuine balsam. This is particularly the case with that sold in capsules, at low prices, in the shops. Pure balsam of copaiba may be recognised by the following characters:--

1. (Ph. E.) It is transparent; free of turpentine odour when heated; soluble in 2 parts of alcohol; and dissolves one fourth of its weight of carbonate of magnesia with the aid of a gentle heat, and continues translucent.

2. (Chevallier.) A drop of the balsam, placed on a piece of unsized paper, and heated until all the essential oil is expelled, forms a semi-transparent, well-defined spot; but if the balsam has been adulterated with a fatty oil, it is surrounded by an oily areola.

3. (Planche.) 2-1/2 parts of balsam shaken with 1 part of solution of ammonia, sp. gr. ·965, forms a mixture which becomes clear and transparent in a few moments, and may be heated to 212° Fahr. without becoming opaque.

4. (Vigne.) Boiled with 50 times its weight of water for 1 hour, it should lose at least half its weight.

5. (Adder.) By agitating the suspected sample with a lye of caustic soda, and setting the mixture aside to repose, the balsam after a time rises to the surface, and the fatty oil present (if any) forms a soapy, thick mass below.

6. ('Journ. de Pharm.,' 1842.) Pure copaiba may be adulterated with 50 per cent. of a fat oil (nut, almond, or castor oil), without it ceasing to give a clear solution with 2 parts of alcohol; but it combines badly with magnesia and ammonia. Excess of alcohol, however, separates the oil in all cases. It was formerly considered that the best test for detecting the fat oils was pure alcohol, to which some caustic potash had been added.

7. (Dr Hager.) Copaiba which is adulterated with Gurgun balsam is not quite clear, and frequently exhibits prisms of gurginic acid under the microscope. The author states that the adulteration may be easily detected by mixing the suspected sample with four volumes of petroleum ether; the mixture at once becomes turbid, and gradually deposits a sediment, which, after half an hour's settling, occupies the same volume as the copaiba operated upon. A mixture of pure copaiba with petroleum ether is clear at first, and either remains clear upon standing or it deposits after several hours a very slight sediment, which merely covers the bottom of the test tube like a thin film. Benzol may be used in place of petroleum ether.

8. (Muter.) Three to four grams of the sample are weighed into a clean, dry flask, and saponified on the water bath with 50 c. c. of alcohol, and a lump of caustic soda weighing not less than 5 grams. When all is dissolved water is added, and the whole washed into a half-pint basin, so as to nearly fill it, and evaporated to 100 c. c. over a low gas flame. Dilute sulphuric acid is then added till the whole just becomes permanently turbid, and then solution of caustic soda is dropped in till it just clears again. By this means a solution is obtained with the least possible excess of alkali, and with a good amount of sodium sulphate. The whole is now to be evaporated to _perfect dryness_ on the water bath, stirring towards the end, so that the sulphate may mix with the soaps, and produce an easy pulverulent residue. The residue is moved from the basin into a small, wide-mouthed, stoppered bottle, treated with 70 c. c. of ether-alcohol, and well shaken up. As soon as it is fairly settled the fluid is filtered off through a _quick_ filter, and this is repeated with two successive quantities of 70 c. c., making 210 c. c. in all of the solvent used. The residue in the bottle and in the filter now consists of sodium oleate and sulphate if the balsam be impure, and of the latter only if pure, with a little trace of the insoluble resin soap already referred to. The contents of the bottle and filter are then dissolved in warm water, and after heating until all smell of ether is gone the whole is boiled freely acidulated with hydrochloric acid, and set to cool.

If, when cold, nothing but a few specks of brown resin should rise to the surface, the balsam is pure; but if an oily layer be formed it is adulterated, and the smell of the separated oleic acid will at once determine whether it is actually castor oil or not.

In the case of the presence of oil, 2 grams of pure and dry white wax are added, and the whole heated till the wax melts with the oleic acid. On cooling, a solid cake is formed, which is detached from the side of the beaker, and the fluid below passed through a filter. The cake is once more melted in boiling water, cooled, detached, dried by gentle pressure between blotting paper, dried in a water-oven in a weighed platinum dish, and then weighed, and the weight of the wax used deducted. The beaker, filter, rod, &c., used are, if at all dirty, dried, extracted with ether, and the residue left, after evaporation, weighed and added to the total.

The calculation is then performed as follows:--

(1.) To the weight in grams found add ·20 for loss of oleic acid in solvent, and then say as 95 : 100 :: total oleic acid.

(2.) Calculate the per-centage from the quantity taken, and from this deduct 6 per cent. for possible altered resin in the balsam. The error, owing to the correction, of course, increases with the amount of oil present; but it is stated to be always an error in the direction of under-estimation, which is the great point for public analysts. When working on 3 to 4 grains with an admixture of not over 25 per cent. the errors due to loss of oleic acid and insoluble resin soap are said to so nearly balance each other, that any correction is unnecessary, and the actual amount of oleic acid found may be taken as correct within a per cent.

9. (B. P.) According to the British Pharmacop[oe]ia, copaiba should be soluble in an equal bulk of benzol.

10. (The evaporation test.) Mr Siebold says: "This is an excellent and exceedingly simple test, but is clumsily applied by many. Instead of boiling the balsam with water for many hours, a small quantity (about 1 to 1·5 gram) of the sample should be carefully heated in a watch-glass until all the oil is driven off, which is the case as soon as the residue has assumed a rich brown colour. A few minutes suffice for the experiment.

"If the remaining resin is perfectly brittle and pulverisable there is no fatty matter present, for 1 per cent. of oil would diminish the brittleness of the resin, so that it cannot be reduced to a fine powder. One per cent. of oil is thus readily detected, and with larger quantities of the adulterant (3 to 5 per cent.) the resin feels quite sticky.

"On heating the resin castor oil and linseed oil may be distinguished by the odour. By mixing the adulterated balsam with ten, twenty, forty, and fifty volumes of pure maranham balsam respectively, and testing each dilution in this manner, it is easy to find in which the oil has been reduced to below 1 per cent., and thus to ascertain whether the adulterant amounted to more than 10, 20, 30, 40, or 50 per cent., and this, I think, would be sufficiently near the mark for the purpose of public analysts."

_Uses, &c._ Balsam of copaiba is considered detersive vulnerary, diuretic, and astringent; and appears to possess a sort of specific power over diseases of the mucous membranes of the urino-genital organs. It is hence a favourite remedy in gonorrh[oe]a, as soon as the first inflammatory symptoms have subsided, antiphlogistic and soothing measures being previously adopted. _Dose_, 20 to 60 drops on sugar, floating on water, or made into an emulsion with yolk of egg or gum arabic, 3 or 4 times daily, if the stomach will bear it. The addition of a few drops of sweet spirits of nitre and laudanum have been recommended, to allay the nausea. By adding 1 dr. of oil of orange (ol. aurantii) to each oz. of the balsam, its flavour becomes far from disagreeable, and it sits well upon the stomach. Copaiba is also given in capsules and pills. See CAPSULES, EMULSION, OIL, PILLS, &c.

_Obs._ Numerous preparations of this article are sold under such names as 'soluble copaiba,' 'specific solution,' 'salt of copaiba,' &c.; none of these appear to possess equal activity and certainty of operation to the natural balsam. As the whole virtue of copaiba as a medicine depends on the essential oil it contains, the value of any of these preparations may be estimated by the quantity of that article which is found in them. In the case of the first two articles above named the quantity is very small indeed, and in the last it is wholly deficient.

The following forms are current in the trade for the reduction (adulteration) of balsam of capivi:--

1. Balsam of copaiba, 4 lbs.; castor oil, 3 lbs.; mix well.

2. Balsam, 7 lbs.; castor oil, 4 lbs; yellow resin, 2 lbs.

3. Equal parts of balsam of copaiba and Canada balsam.

4. To the last add Venice turpentine, 1 lb.

5. Balsams of Canada and copaiba and nut or castor oil, equal parts.

6. Copaiba, 7 lbs.; nut oil, 3 lbs.; yellow resin, 2 lbs.; Canada balsam, 1 lb. Used to fill the cheap capsules; and to sell in the lower parts of London and in the manufacturing districts. See also COPAIBA, FACTITIOUS (_below_).

=Copaiba, Facti''tious.= _Syn._ COBAI'BA FACTI''TIA, BAL'SAMUM COPAI'BÆ FACTI''TIUM, L. _Prep._ 1. Castor oil (warm), 7 quarts; copaiba bottoms, 1 quart; mix, and filter through flannel.

2. Castor, oil, 1 gal.; yellow resin, 3 lbs.; Canada balsam, 2 lbs.; oil of juniper, 2 oz.; oil of savin, 1 oz.; essences of orange and lemon, of each 1/2 oz.; powdered benzoin, 1 oz.; melt the resin with the castor oil and benzoin, and when nearly cold add the essences.

3. Canada balsam, 9 lbs.; castor oil, 7 lbs.; yellow resin, 1 lb.; Venice turpentine, 2 lbs.; oils of rosemary, juniper, and savin, of each 1 dr.; essential oil of almonds, 20 drops.

4. Canada balsam, 3 lb.; Venice turpentine, 1 lb.; oils of fennel, juniper, and savin, of each q. s.

Used chiefly to fill capsules. It is readily distinguished from balsam of copaiba by the proper tests. (See _above_.) Train oil or nut oil is frequently substituted for the castor oil.

=Copaiba and Ka'li.= _Syn._ COPAIBA CUM POTASSÂ, L. _Prep._ Carbonate of potassa and water, of each, equal parts; dissolve, and add gradually, transparent balsam of copaiba, until the fluid, at first milky, turns quite clear. Resembles miscible copaiba (see _below_).

=Copaiba, Miscible.= _Prep._ From balsam of copaiba (pure and transparent), mixed with half its volume of solution of potassa made of double the strength ordered in the B. P.

_Obs._ As different samples of copaiba often require slightly different quantities of the solution of potassa, it is best to mix the two gradually and cautiously together. Should the mixture be opaque, a little more of one or other of the ingredients, as the case may be, will render it clear. No heat must be used. This article is miscible with water, with which it forms a kind of milk; and from containing all the volatile oil of the copaiba, is a very valuable preparation. Its activity is considered equal to that of the balsam itself, and it is given in similar doses.

=Copaiba, Sol'uble.= _Syn._ COPAI'BA SOLUBIL'IS, L. _Prep._ 1. Heat miscible copaiba in an earthen, glass, or bright-tinned copper vessel, to nearly the boiling-point, pour it while still hot in a separator, cover it up, and allow it to cool very slowly. After a few days, draw off the clear portion from a cock or hole placed at or near the bottom of the vessel, observing to reject the first few drops which pass through, and to stop the stream before any of the floating oil (_oleum copaibæ_) reaches the orifice. A very little concentrated liquor of potassa, added before applying the heat, renders it more soluble. Thick, transparent, soluble in pure water, and resembles the natural balsam in appearance.

2. Balsam of copaiba and solution of potassa (B. P.), equal parts, by volume; mix, boil for a few minutes, and then proceed as before. Thinner than the last.

_Prop._ Less powerful than miscible copaiba, but it sits better on the stomach, and is about four times as strong as specific solution of copaiba. See SOLUTION.

=Copaiba, Res'in of.= _Syn._ COPAI'BÆ RESI'NA, L. The residuum of the process of distilling the oil of copaiba from the balsam. It consists principally of copaibic acid. It has been recommended for gonorrh[oe]a, but is nearly inert, even in 1/2 oz. or 3/4 oz. doses. See OIL.

=Copaiba, Salt of.= _Syn._ SAL COPAI'BÆ, L. There are two preparations sold under this name; the one, crude copaibic acid; the other, copaibate of an alkali. Neither of them possesses the valuable properties of copaiba, which reside almost entirely in its essential oil, "We have taken the 'sal copaibæ,' and have watched its action on others, but have not been able to perceive any good effects to result from its administration." (Cooley.)

=COPAI'BIC ACID.= _Syn._ CAPIV'IC ACID. YELLOW RESIN OF COPAIBA. An amber-coloured, brittle, semi-crystalline, resinous substance, obtained from resin of copaiba, soluble in alcohol, rectified spirit, ether, and oils, reddens litmus paper, and forms salts with the bases, called copaibates.

=CO'PAL.= _Syn._ COPAL', GUM COPAL. A resinous substance, which exudes spontaneously from various trees belonging to the genera _Hymenæa_, _Guibourtia_, and _Trachylobium_. The varieties commonly met with in commerce are East Indian copal, or anine, which is the produce of _Hymenæa Courbaril_, and West Indian copal, obtained from numerous species.

_Prop._ When of good quality it is too hard to be scratched by the nail, has a conchoidal fracture, and a sp. gr. ranging from 1·059 to 1·072. Unlike other resins, it is dissolved with difficulty by alcohol and essential oils; and this property, combined with its extreme hardness, renders it very valuable for making varnishes. See VARNISH.

=COP'PER.= Cu. _Syn._ CU''PRUM, L.; CUIVRE, Fr.; KUPFER, Ger.

_Sources._ Metallic copper (native copper) is found in many parts of the globe, diffused in isolated particles in the form of thin laminæ, in loose grains intermixed with quartz (copper sand, copper barilla), in dendritic pieces, and in solid blocks, occasionally of many tons weight. The richest deposits of native copper are those of Lake Superior, in North America. More frequently and more abundantly it occurs as an ore, _e.g._ red oxide, black oxide, green carbonate of copper or mal'achite, blue carbonate of copper, vitreous sulphide of copper, purple copper, copper pyrites, or yellow copper ore, with sulphur, antimony, or arsenic, and other metals (true grey copper ore or fah'lerz), as an impure hydrated silicate (chrys'ocolla), and as an impure hydrated oxychloride (atac'amite). The most abundant and important ore is copper pyrites. It is principally obtained from the mines of Cornwall, Devonshire, and Cuba. The carbonates of copper are now largely imported from Australia; the metal produced by smelting them is generally of the best quality.

_Prep._ We will not attempt to give a minute description of the various complex processes by which the reduction of copper from its ores is effected, but will merely give an outline of the common or Welsh process. This process includes six distinct operations, as follows:--1. The ore (copper and iron pyrites), containing from 8 to 10% of copper, is roasted in a reverberatory furnace, called a 'calciner,' by which much of the sulphide of iron is converted into oxide. 2. The calcined ore is melted with 'metal slag' (a product of a subsequent operation--No. 3), in a melting furnace called the 'ore furnace.' The products are a regulus, termed 'coarse metal,' containing about 35% of copper, and 'ore-furnace slag,' which is thrown away. Much of the iron, and the whole of the so-called earthy matter of the ore, are thus separated as slag. 3. The coarse metal, having been granulated by causing it to flow from the furnace into water, is calcined with free access of air in a calciner, and a considerable amount of sulphur is expelled. 4. The calcined granulated, coarse metal is melted with the addition of matters rich in oxides of copper, namely, 'roaster' and 'refinery slags' (from the two remaining operations, Nos. 5 and 6, respectively), and native carbonates of copper, or ores containing oxide of copper. The products are a regulus, termed 'metal,' which contains about 75% of copper, and metal slag (see No. 2). The metal should be in the state of 'white metal,' compact and brittle, with a feeble metallic lustre and a dark, bluish-grey colour. It is tapped off into sand moulds. 5. The pigs of regulus obtained by the last operation are roasted in a furnace through which air passes. The temperature is so regulated that the regulus may be melted in from 6 to 8 hours. The slag is skimmed off, and after a time the heat is lowered, to allow the regulus to solidify. It is again melted and tapped into sand moulds, the product being called 'blister copper.' 6. This, the last operation, is termed 'refining.' From 6 to 8 tons of blister copper, in pigs, are melted in a furnace, and kept exposed for about 15 hours to the oxidising influence of the air. The slag is skimmed off through the end opening. When the oxidation has been sufficiently prolonged, anthracite or free-burning coal, as pure as possible, is thrown upon the surface of the metal, and after a short time the thick end of a long birch or oak pole is plunged into the molten mass. This part of the operation is termed 'poling.' The wood in contact with the copper is rapidly decomposed; much gas is evolved, which causes the metal to be splashed about, and every part of it to be exposed to the reducing action of the coal. When the refiner finds the metal to be at the state of 'tough pitch,' the pole is taken out, and the coal pushed back from the end opening, through which the copper is then ladled out as quickly as possible, and cast into suitable moulds. For full details of this and other processes, the reader is referred to Dr Percy's work on 'Metallurgy,' and Ure's 'Dictionary of Arts, Manufactures, and Mines.'

In the laboratory copper is commonly employed under the following forms:--

1. BEAN-SHOT COPPER. Produced by simply lading the melted copper from the refining furnace into hot water. In small lumps like peas and beans; hence its name. Used to make alloys, solutions, &c.

2. ELECTROTYPE COPPER. A very pure form, obtained by decomposing sulphate of copper in an electrotype apparatus. It does not contain lead, whereas most varieties of commercial copper do contain that metal.

3. FEATHER-SHOT COPPER, GRANULATED C. Produced by lading the refined copper from the furnace into cold water. In small pieces, with a feathered edge. Used to make calamine, brass, solution of copper, &c.

4. COPPER IN PLATES OR FOIL. Those of commerce (best, annealed) are generally employed.

5. COPPER IN POWDER.--_a._ A solution of sulphate of copper is heated to the boiling-point, and precipitated with distilled zinc; the precipitated copper is then separated from the adherent zinc by dilute sulphuric acid, washed with water, and dried by exposure to a moderate temperature.

6. COPPER PREPARED BY THE HYDROMETALLURGICAL METHOD.--One of the oldest processes of this kind, is that known as the 'cementation' method, and consists in precipitating copper from a solution of the sulphate of the metal, by means of metallic iron. In some mines solutions of the sulphate are met with occurring naturally, in others they are prepared artificially by treating poor ores containing oxide of copper, with sulphurous acid or diluted sulphuric acid, and sometimes by roasting copper pyrites and afterwards washing them with water to extract the resulting sulphate. The copper obtained by any of the above processes is called 'cementation copper.' In the Isle of Anglesea the cementation liquid containing the dissolved sulphate of copper, is first run into large vessels where the suspended matters are allowed to subside; from these it is conveyed to tanks containing old scrap-iron, which serves as the precipitating agent. The scrap-iron is occasionally stirred up so as to renew the metallic surface presented to the solution. The muddy liquor which contains metallic copper as a spongy mass, besides impurities, is run into vessels where it deposits the copper, which after the removal of the supernatant fluid, is removed and dried in a furnace.

7. WET PROCESS. (Henderson's process.) The ores (Spanish and Portuguese pyrites) treated by this method vary very slightly in composition, rarely containing much more than 3 per cent. of copper, nearly 50 per cent. of sulphur, from 43 to 44 per cent. of iron, with small quantities of lead, arsenic, zinc, lime, &c. The ores are first employed by the vitriol manufacturers, as a source of sulphuric acid. In the process of burning they lose about 30 per cent. of their sulphur. The copper is extracted from the residue by subjecting this latter to the following processes, which are thus described in the 'Encyclopædia Brittanica.'

I. _Grinding._ The burnt ore, as received from the acid burners, is first mixed with about 15 per cent. of common salt, and ground to a fine powder by passing it between a pair of heavy cast-iron rolls. As the amount of sulphur left in the burnt ore is apt to vary, it is necessary to ascertain its proportion in each parcel of burnt pyrites. When the sulphur falls short of the proportion necessary for effecting the decomposition which follows, a sufficient quantity of 'green' or unburned pyrites is added to produce a proper balance. If, on the other hand, the sulphur has been sufficiently extracted, dead roasted ore is added.