Cooley's Cyclopaedia of Practical Receipts Volume I Part 151

Ammonia gives a blue precipitate, slightly soluble in excess, giving a brownish-red colour.--2. Pota.s.sa gives a blue precipitate, turning to violet and red when the solution is heated.--3. Carbonate of ammonium and carbonate of sodium give pink precipitates; that from the former is soluble in excess.--4. Cyanide of pota.s.sium gives a yellowish-brown precipitate, soluble in excess; and the clear solution, after being boiled, is unaffected when mixed with hydrochloric acid.--5. Sulphuretted hydrogen produces no change in acid solutions.--6. Sulphydrate of ammonium gives a black precipitate in neutral solutions.--7. Melted with borax, before the blowpipe, it gives a bead of a magnificent blue colour, almost verging on black, if much is present. Phosphate of sodium and ammonium give a similar bead; but the colour is less intense.

=Cobalt, Ac'etate of.= Co(C_{2}H_{3}O_{2})_{2}. _Prep._ From the carbonate or protoxide and acetic acid. It forms a sympathetic ink which turns blue when heated.

=Cobalt, a.r.s.eniate of.= Co_{3}2AsO_{4}, 8H_{2}O. A hydrated native tricobaltous a.r.s.eniate of cobalt, known as "cobalt bloom."

=Cobalt, Car'bonate of.= CoCO_{3}. _Prep._ By adding an alkaline carbonate to a solution of the nitrate or sulphate. A pale peach-coloured powder, soluble in acids. It contains some hydrate.

=Cobalt, Chlo"ride of.= CoCl_{2}. _Syn._ HYDROCHLO"RATE OF C., MU"RIATE OF C. _Prep._ By dissolving the carbonate or protoxide in hydrochloric acid; the solution deposits deep rose-red crystals on standing, which contain water. By evaporating the solution by heat, anhydrous blue crystals of the chloride are obtained. Both of them yield a deep rose-red solution with water, which is turned green by a little acid. This solution forms a well-known sympathetic ink, the traces of which become blue when heated. If the solution contains either chloride of iron or chloride of nickel, the traces become green. (Klaproth.) The addition of a little nitrate of copper to the above solution forms a sympathetic ink, which by heat gives a very rich greenish-yellow colour. (Ure.) The addition of a very little common salt makes the traces disappear with greater rapidity, on the withdrawal of the heat. In each case, when the paper is laid aside, moisture is absorbed, and the writing once more disappears. If, however, much heat has been used the traces become permanent.

=Cobalt, Ni'trate of.= Co(NO_{3})_{2}. _Prep._ As the last, subst.i.tuting nitric for hydrochloric acid; it forms deliquescent crystals.

=Cobalt, Ox'alate of.= CoC_{2}O_{4}. _Prep._ As the acetate, from oxalic acid and the carbonate or protoxide; or by double decomposition.

=Cobalt, Ox'ides of.= Of these there are two, the protoxide and the sesquioxide; besides an acid compound of cobalt and oxygen, to which the name cobaltic acid has been given.

1. =Cobalt, Protox'ide of.= CoO. _Syn._ OXIDE OF COBALT, GREY O. OF C., BLACK O. OF C., COBALT BLACK. _Prep._ 1. By precipitating a solution of sulphate of chloride of cobalt with carbonate of sodium, and washing, drying, and igniting the powder which subsides.

2. By boiling powdered bright-white cobalt ore (from Cornwall) in dilute nitric acid, and adding a solution of carbonate of pota.s.sium, very gradually, until the clear liquor, after the impurities have settled, becomes of a rose colour; and then as long as a precipitate falls; wash and dry it as before.

_Prop., &c._ A grey powder, turning black on exposure to the air; strongly basic; and forming salts with the acids, having a fine red tint. It is remarkable for the magnificent blue colour it communicates to gla.s.s, and by this character its presence may be readily detected before the blowpipe; the substance to be examined being fused with borax on a loop of platinum wire. Used to make blue colours for painters, stains and glazes for enamellers, gla.s.s-melters, potters, &c. In _medicine_ it has occasionally been given as a remedy for rheumatism.

2. =Cobalt, Sesquiox'ide of.= Co_{2}O_{3}. _Syn._ PEROX'IDE OF COBALT. A black, insoluble, neutral powder, obtained by mixing solutions of cobalt and of chloride of lime; or, by heating the protoxide to redness in an open vessel.

=Cobalt, Phos'phate of=. Co_{3}(PO_{4})_{2}. _Prep._ As the acetate, subst.i.tuting phosphoric for acetic acid. An insoluble purple powder, which, when heated along with eight times its weight of gelatinous alumina, produces a blue pigment (COBALT BLUE, COBALT ULTRAMARINE), almost equal in beauty to ultramarine. (See _below_.)

=Cobalt, Sul'phate of.= CoSO_{4}. By boiling sulphuric acid on the metal, or by dissolving the oxide in the acid. It forms reddish crystals, soluble in 24 parts of water.

=Cobalto-Ultramarine.= A fine blue pigment, prepared by mixing freshly precipitated alumina, 8 parts, with phosphate or a.r.s.eniate of cobalt, 1 part; drying the mixture, and then slowly heating it to redness. By daylight the colour is pure blue, but by artificial light it is violet.

See BLUE PIGMENTS.

=COCA. Erythroxylon Coca.= This plant is grown largely in Peru and Bolivia. The Bolivian coca is said to be much superior to the Peruvian.

The best kind is believed to come from the province of Yungas, and the most inferior description from Peru. The consumption of Coca in Peru, Bolivia, and in some of the provinces of the Argentine Confederation is enormous. In small doses it is supposed to act as a stimulant and to aid digestion; in large ones it is said to possess dangerous narcotic properties. The mountaineers in South America state they are enabled to reach high elevations without difficulty of respiration, and to stave off the feeling of hunger by chewing the leaves during their ascents. "Good quality coca should have its leaves unbroken, of a medium size, bright green in colour, and of an odour somewhat combining that of hay and chocolate. The taste is bitter, and when masticated, coca is said to yield easily to the teeth. Infused in hot water, it has a beautiful green colour, which, however, is much darker from inferior leaves. An infinite number of varieties are recognised between the best and the lowest quality, which has a disagreeable smell and a colour resembling roasted coffee. The leaves are also bent and broken, scarcely a whole leaf being found amongst them."[249] The statements as to the effects of coca are conflicting, as will be seen from what follows:--Sir R. Christison, writing to the 'British Medical Journal,' April 29th, 1876, states he was hardly sensible of the fatigue of two mountain descents made from Ben Vorlich after chewing coca leaves. That, as a consequence of his doing so, hunger and thirst were suspended for a long time, but that eventually appet.i.te and digestion were unaffected. He made trial during the first descent of 60 grains, and of the second, undertaken eight days after, of 90 grains of coca.

[Footnote 249: 'Pharmaceutical Journal.']

Mr Dowdeswell, in a communication to the 'Lancet,' May 6th, 1876, says that, contrary to the experience of Sir R. Christison, he found no decided effects produced after consuming nearly a pound of the leaves, which were taken in all forms and at all hours for nearly a month. They failed to produce the slightest excitement, not giving rise even to the feeling of buoyancy and exhilaration which is experienced from mountain air or a draught of spring water.

In the 'Canadian Pharmaceutical Journal' for August, 1877, there is a paper by Mr Shuttleworth, wherein results the opposite to those of the last-named gentlemen are recorded. Mr Shuttleworth states that the members of a club established at Toronto for the purpose of playing at La Crosse, a very violent and fatiguing pastime, were almost unanimous in ascribing their invariable success over their numerous adversaries to the use of coca leaves during their contests; their opponents not employing the plant. The antagonists of the club were men of stronger build and physique as well as more accustomed to out-of-door pursuits, and were besides trained players.

The same writer says that in South America care is taken to procure the leaves in as fresh a state as possible, and that many writers have ascribed the want of effect to old leaves.

The 'British Medical Journal' of March 10th, 1877, contains a communication from Dr T. McBean, who states that he has found the administration of coca leaves useful in typhoid fever, as well as in other febrile diseases.

=CO'COA= (ko'-ko). _Syn._ CACA'O. An alimentary substance formed of the roasted seeds of the _Theobroma Cacao_, a tree belonging to the natural order _Byttneriaceae_. This definition is equally applicable to chocolate, but we commonly cla.s.s the preparations containing sugar and flavouring substances under that head, and the unsweetened and cheap preparations under COCOA. The cocoa-seed or berry must not be confounded with the cocoa-nut, which is the fruit of a palm (_Cocus nucifera_). The cocoa tree is a native of Mexico, and is now more or less extensively grown throughout Central America, Brazil, Peru, Venezuela, Caraccas, Ecuador, Grenada, Demerara, Essequibo, Guayaquil, and Surinam; with some of the West India Islands, foremost among which stands Trinidad. It has also been introduced with more or less success into Africa, the Mauritius, Madagascar, Bourbon, the East Indies, Australia, and the Philippine Islands. The following is a list of the princ.i.p.al kinds of cocoa, in the order of their commercial value:--Caraccas, Surinam, Trinidad, Grenada, Jamaica, Dominica, Guayaquil, Venezuela, Bahia, Brazil, St. Lucia. It seems probable that some of the highest kinds of cocoa do not find their way into this country, but are consumed by the inhabitants of Spain.

_Prep._ The pods containing the seeds are gathered when ripe, and after having lain for a day and a night are opened, and the seeds, which are taken out by hand, are submitted to what is termed the sweating process.

They are first placed on a sloping floor or in baskets, so that the chief part of the pulp in which they are enveloped may drain off, and are then shut up in a close box, and left for 24 to 48 hours, according to the season and weather, after which they are turned out in the sun to dry.

Upon a nice performance of the sweating process, which may be likened to malting, the value of the cocoa greatly depends. When quite dry, the seeds are packed in barrels or bags, and are ready for shipment. The process of roasting is effected in a metal cylinder, with holes at each end, through which the vapour generated is allowed to escape. When the aroma is sufficiently developed the seeds are cooled, and then pa.s.sed to a 'kibling mill,' which removes the husks and skins from the 'nibs' (see _below_).

_Prop., Const.i.tuents, &c._ Cocoa, when unadulterated, forms a wholesome and highly nutritious beverage. Its active principle is theobromine, an alkaloid greatly resembling caffeine, the active principle of coffee and tea. A peculiar concrete oil, called cocoa-b.u.t.ter, or, more correctly, b.u.t.ter of cacao, is another important const.i.tuent, forming more than half the weight of the seed. The presence of about 20% of alb.u.men gives to cocoa its nutritive character.

_Average composition of cocoa seeds._--(w.a.n.klyn.)

+-------------------------------+-----------+ Per cent. Fat (cocoa b.u.t.ter) 5000 Alb.u.men, fibrine, and gluten 1800 Starch 1000 Gum 800 Colouring matter 260 Water 600 Theobromine 150 Ash 360 Loss 030 +-------------------------------+-----------+ 10000 +-------------------------------+-----------+

Dr Letheby calculated that a pint of cocoa made with 1 oz. of ground nibs would contain the following proportions of nutritious matters:--

+-------------------------------+--------------+ Nitrogenous matters 962 grains Patty matter 2188 " Gum, sugar, and extractive 656 " Mineral matters 175 " +-------------------------------+--------------+ Total extracted 3981 +-------------------------------+--------------+

_Adult._ Much of the cheap stuff sold as genuine cocoa is shamefully adulterated. Out of 68 samples of cocoa and chocolate examined by the 'Lancet' commission, 39 contained coloured earthy substances, as reddle, Venetian red, umber, &c. To some, chalk or plaster of Paris had been added, for the purpose of increasing the weight. Many of the samples consisted of sugar and starch, with only sufficient cocoa to impart a flavour. Cocoas containing a moderate amount of arrow-root or other starch must not be considered adulterated articles, for it is impossible to render cocoa soluble, or rather emulsive, without the addition of some diffusible substance.

[Ill.u.s.tration]

[Ill.u.s.tration]

[Ill.u.s.tration]

By an examination of the ash the presence of any mineral adulterant may be detected. Mr Blyth says the amounts of ash in genuine cocoa should never exceed 5 per cent. The seed of the cocoa consists of husk and seed proper.

Under the microscope the husk exhibits on its surface a number of tubular fibres, filled with granular matter and minute corpuscles. It consists of three membranes; the first being a single layer of elongated cells; the second (forming the chief portion of the husk) of angular cells, enclosing mucilage, and also containing a few spiral vessels and woody fibres. The third membrane is very thin and delicate, and is made up of small angular cells containing minute globules of fat. The seed is composed of minute cells containing starch. The starch corpuscles are very small, with a trace of inulin. (See cuts on previous page.)

=Cocoa, Flake.= This is formed by grinding the nibs in a mill, consisting of two cones, working one inside the other. Pure flake cocoa is not a diluted or amalgamated article; in other words, it contains no sugar, and but a trace of starch.

=Cocoa Nibs.= The bruised, roasted seeds, freed from husk and membrane.

They ought to be of a dull-red or greyish colour, but are frequently given a bright-red colour by a coating of Venetian red.

=Cocoa, Sol'uble.= From cocoa nibs and substances which are readily soluble or diffusible in water, ground together. Sugar and sago or arrow-root are the diluents used by respectable makers, but all kinds of starches, coloured with Venetian red, are used for the trashy articles which are sold to the poor. No form of cocoa is really soluble, but by the addition of easily diffusible substances an article is produced which is capable of forming an emulsion with boiling water. The following are the princ.i.p.al varieties of the so-called soluble cocoa:--

1. COCOA, GRANULATED. From cocoa nibs and sufficient sugar and arrow-root to keep the fatty particles from forming a pasty ma.s.s. As it is impossible to granulate the nibs without the admixture of some other substance, those makers who declare that their granulated cocoas are perfectly pure do not act honestly towards their customers.

2. COCOA, h.o.m.oPATHIC. A kind of soluble cocoa prepared with arrow-root, but without sugar.

3. COCOA, ICELAND-MOSS. From cocoa and Iceland moss, freed from its bitter principle, cetrarine. This form of cocoa was introduced by Messrs Dunn and Hewett, and is said to form a very valuable article of diet for invalids.

4. COCOA, MARAVILLA. This is stated to be "the perfection of prepared cocoa." It consists of cocoa, sugar, and sago flour, the last two being in great excess.

5. COCOA, CARACCAS. This is similar to the last, being a mixture of cocoa, sugar, and sago flour. The cocoa used in its manufacture is said to be imported from the Caraccas, on the north coast of South America, and to possess a peculiarly delicious flavour.

The amount of flour or starch in these so-called soluble cocoas frequently exceeds 40 per cent., and the amount of sugar 20 per cent. They have been not inaptly called "soups."

Within the past year or two a new variety of soluble cocoa has been brought into the market. It is sold under various names, thus, 'Theobromine, or Concentrated Cocoa,' 'Cocoa Essence,' 'Cocoatina,' &c. We have examined many of these varieties, and find them to consist of pure cocoa deprived of about two thirds of its fat. It appears very suitable for people of weak digestion.

_Obs._ No warm drink that we take approaches cocoa in its nutritive character, because, while performing to a certain extent the exhilarating work of coffee or tea, it presents to the stomach a very considerable quant.i.ty of nitrogenous and carbonaceous matter; this advantage is partly due to the fact that cocoa is taken in the form of an emulsion, instead of an infusion or decoction.

COCOA FOR THE TABLE is readily prepared from the soluble varieties by simply pouring boiling water upon the powder. From cocoa nibs, or flaked cocoa, the beverage is prepared by first pouring boiling water upon them, and then allowing the ma.s.s to simmer from 4 to 6 hours. The cocoa must on no account be allowed to boil, for in that case a coagulum will be formed, which cannot be dissolved in water.

=COCOA-NUT OIL.= A species of vegetable b.u.t.ter obtained from the common cocoa nut--the fruit of _Cocos nucifera_, the cocoa palm. It is separated from the dried kernel by hydraulic pressure. It contains olein, and a solid fat often used as a candle material. Large plantations of the cocoa palm, connected with Price's candle company, exist in Ceylon. Cocoa-nut oil is often confounded with cocoa- or cacao-b.u.t.ter, which is the produce of a very different plant, namely, _Theobroma cacao_. See COCINIC ACID, COCOA, STEARIC ACID, &c.

=COC'CULUS IND'ICUS.= _Syn._ INDIAN BERRIES, INDIAN c.o.c.kLES, LEVANT NUT, LOUSE GRAINS; BAC'CA ORIENTA'LIS, COCOULUS PISCATOR'IUS, &c., L. The fruit of the _Anamirta paniculata_, a shrub which abounds on the sandy sh.o.r.es of Malabar, and several other islands in the Indian Ocean. The kernels should fill at least two thirds of the fruit.