Cooley's Cyclopaedia of Practical Receipts Volume Ii Part 26

"To succeed experimentally in bringing the molecules of a gas into the closest possible proximity, and thus to obtain its liquefaction, certain indispensable conditions are necessary, which I thus sum up:

"1. To have a gas that must be perfectly pure and without a trace of foreign gas.

"2. To have at one's disposal very powerful means of compression.

"3. To obtain an intense degree of cold, and the abstraction of heat at these low temperatures.

"4. To have a large surface of condensation maintained at these low temperatures.

"5. To have the power of utilising the expansion of the gas under considerable pressure to the atmospheric pressure, which expansion added to the preceding means compels liquefaction.

"With these five conditions fulfilled, we may formulate the following problem.

"When a gas is compressed at 500 or 600 atmospheres, and kept at a temperature of -100 or 140, and then let expand to the pressure of the atmosphere, one of two things must occur. Either the gas, obeying the action of cohesion, liquefies and yields its heat of condensation to the portion of the gas, which expands and is lost in the gaseous form; or under the hypothesis that cohesion is not a natural law, the gas pa.s.ses beyond absolute zero, that is to say, it becomes inert, a dust without consistence. The work of expansion would be impossible, and the loss of heat absolute."

Spite of M. Cailletet's supposition that nitrogen would prove a very incoercible gas, his experiments showed the contrary, since he found that it easily condensed under a pressure of about 200 atmospheres and at a temperature of 13 C., the conditions as to its sudden expansion being observed.

Hydrogen, the lightest of all the gases, which M. Cailletet could only procure in the form of mist, was unmistakably liquefied by M. Pictet within less than a fortnight afterwards, under a pressure of 650 atmospheres and 140 of cold.

The tap which confined the gas at this pressure, being opened, a jet of a steel blue colour escaped from the orifice, accompanied by a hissing sound, like that given off when a red-hot iron is dipped into cold water.

The jet suddenly became intermittent, and a shower of solid particles of the hydrogen fell to the ground with a crackling noise. The hydrogen was obtained by the decomposition of formiate of potash by caustic potash, the gas thus yielded being absolutely pure.

Cailletet states that he succeeded perfectly in liquefying atmospheric air, previously deprived of moisture and carbonic acid, but he omits to mention the pressure and reduction of temperature to which the air was subjected. He liquefied nitric oxide at the pressure of 104 atmospheres and at a temperature of -11 C.

Carbonic anhydride is liquefied on the large scale by condensing it in strong vessels of gun-metal or boiler-plate. Thilorier was the first to procure it in a solid condition. It requires a pressure of between 27 and 28 atmospheres at 32 F. (Adams.) The liquefied acid is colourless and limpid, lighter than water, and four times more expansible than air; it mixes in all proportions with ether, alcohol, naphtha, oil of turpentine, and sulphide of carbon; and is insoluble in water and fat oils. When a jet of liquid carbonic anhydride is allowed to issue into the air from a narrow aperture, such an intense degree of cold is produced by the evaporation of a part, that the remainder freezes to a solid (solid carbonic anhydride), and falls in a shower of snow. This substance, which may be collected, affords a means of producing extreme cold. Mixed with a little ether, and poured upon a ma.s.s of mercury, the latter is almost instantly frozen. The temperature of this mixture in the air was found to be -106 Fahr.; when the same mixture was placed beneath the receiver of an air-pump, and exhaustion rapidly performed, the temperature sank to -166. This degree of cold was employed in Faraday's last experiments on the liquefaction of gases.

=LIQUEUR.= [Fr.] _Syn._ CORDIAL. A stimulating beverage, formed of weak spirit, aromatised and sweetened. The manufacture of liqueurs const.i.tutes the trade of the 'compounder,' 'rectifier,' or 'liquoriste.'

The materials employed in the preparation of liqueurs or cordials are rain or distilled water, white sugar, clean flavourless spirit, and flavouring ingredients. To these may be added the substances employed as 'finings,'

when artificial clarification is had recourse to.

The utensils and apparatus required in the business are those ordinarily found in the wine and spirit cellar; together with a copper still, furnished with a pewter head and a pewter worm or condenser, when the method 'by distillation' is pursued. A barrel, hogshead, or rum puncheon, sawn in two, or simply 'unheaded,' as the case may demand, forms an excellent vessel for the solution of the sugar; and 2 or 3 fluted funnels, with some good white flannel, will occasionally be found useful for filtering the aromatic essences used for flavouring. Great care is taken to ensure the whole of the utensils, &c., being perfectly clean and 'sweet,' and well 'seasoned,' in order that they may neither stain nor flavour the substances placed in contact with them.

In the preparation or compounding of liqueurs, one of the first objects which engages the operator's attention is the production of an alcoholic solution of the aromatic principles which are to give them their peculiar aroma and flavour. This is done either by simple solution or maceration, as in the manufacture of tinctures and medicated spirits, or by maceration and subsequent distillation. The products, in this country, are called ESSENCES or SPIRITS, and by the French INFUSIONS, and are added to the solution of sugar (SYRUP or CAPILLAIRE) or to the dulcified spirit, in the proportions required. Grain or mola.s.ses spirit is the kind usually employed for this purpose in England. As before observed, it should be of the best quality; as, if this is not the case, the raw flavour of the spirit is perceptible in the liquor. Rectified spirit of wine is generally very free from flavour, and when reduced to a proper strength with clear soft water, forms a spirit admirably adapted for the preparation of cordial liquors. Spirit weaker than about 45 o. p., which has been freed from its own essential oil by careful rectification, is known in trade under the t.i.tle of 'pure,' 'flavourless,' 'plain,' or 'silent spirit.'

Before macerating the ingredients, if they possess the solid form, they are coa.r.s.ely pounded, bruised, sliced, or ground, as the peculiar character of the substance may indicate. This is not done until shortly before submitting them to the action of the menstruum; as, after they are bruised they rapidly lose their aromatic properties by exposure to the air. When it is intended to keep them for any time in the divided state they should be preserved in well-corked bottles or jars. The practice of drying the ingredients before pounding them, frequently adopted by ignorant and lazy workmen for the sake of lessening the labour, is, of course, even more destructive to their most valuable qualities than mere exposure to the air. The length of time the ingredients should be digested in the spirit should never be less than 5 or 6 days, but a longer period is preferable when distillation is not employed. In either case the time may be advantageously extended to 10 days or a fortnight, and frequent agitation should be had recourse to during the whole period. When essential oils are employed to convey the flavour, they are first dissolved in a little of the strongest rectified spirit of wine, in the manner explained under ESSENCE; and when added to the spirit, they are mixed up with the whole ma.s.s as rapidly and as perfectly as possible. In managing the still, the fire is proportioned to the ponderosity of the oil or flavouring substance, and the receiver is changed before the faints come over; as these are unfitted to be mixed with the cordial. In many cases the addition of a few pounds of common salt to the liquor in the still facilitates the process and improves the product. Ingredients which are not volatile are, of course, always added after distillation. The stronger spirit is reduced to the desired strength by means of either clear soft water or the clarified syrup used for sweetening. The sugar employed should be of the finest quality, and is preferably made into capillaire or syrup before adding it to the aromatised spirit; and not until this last has been rendered perfectly 'fine' or transparent, by infiltration or clarification, as the case may demand. Some spirits or infusions, as those of aniseed, caraway, &c., more particularly require this treatment, which is best performed by running them through a clean wine bag, made of rather fine cloth, having previously mixed them with a spoonful or two of magnesia; but in all cases clarification by simple repose should be preferred. Under proper management, liqueurs or cordials prepared of good materials will be found perfectly 'clear' or 'bright' as soon as made, or will become so after being allowed a few days for defecation; but in the hands of the inexperienced operator, and when the spirit employed is insufficient in strength or quant.i.ty, it often happens that they turn out 'foul' or 'milky.' When this is the case, the liquid may be 'fined down' with the whites of 12 to 20 eggs per hogshead; or a little alum, either alone or followed by a little carbonate of sodium or pota.s.sium, both dissolved in water, may be added, in the manner described under FININGS.

An excellent and easy way of manufacturing cordial liquors, especially when it is inconvenient to keep a large stock on hand, is by simply 'aromatising' and 'colouring,' as circ.u.mstances or business may demand, spirit 60 or 64 u. p., kept ready sweetened for the purpose. To do this to the best advantage, two descriptions of sweetened spirit should be provided, containing respectively 1 lb. and 3 lbs. of sugar to the gallon.

From these, spirit of any intermediate sweetness may be made, which may be flavoured with any essential oil dissolved in alcohol, or any aromatised spirit or 'infusion' (see _below_), prepared either by digestion or distillation. As a general rule, the concentrated essences, made by dissolving 1 oz. of the essential oil in 1 pint of the strongest rectified spirit of wine, will be found admirably adapted for this purpose. These essences, which should be kept in well-corked bottles, are employed by dropping them cautiously into the sweetened spirit until the desired flavour is produced. During this operation the liquor should be frequently and violently shaken to produce complete admixture. If by any accident the essence is added in too large a quant.i.ty, the resulting 'milkiness' or excess of flavour may be removed by the addition of a little more spirit, or by clarification. In this way the majority of the liqueurs in common use may be produced extemporaneously, of nearly equal quality to those prepared by distillation. For those which are coloured, simple digestion of the ingredients is almost universally adopted. The "process by distillation" should, however, be always employed to impart the flavour and aroma of volatile aromatics to the spirit, when expense, labour, and time are of less importance than the production of a superior article.

The French liqueuristes are famed for the preparation of cordials of superior quality, cream-like smoothness, and delicate flavour. Their success chiefly arises from the employment of very pure spirit and sugar (the former in a larger proportion than that adopted by the English compounder), and in the judicious application of the flavouring ingredients. They distinguish their cordials as 'eaux' and 'extraits'

(waters, extracts), or liqueurs which, though sweetened, are entirely devoid of viscidity; and 'baumes,' 'cremes,' and 'huiles' (balms, creams, oils), which contain sufficient sugar to impart to them a syrupy consistence. The greatest possible attention is given to the preparation of the aromatised or flavouring essences, in France called 'infusions.'

These are generally made by macerating the aromatic ingredients in spirit at about 2 to 4 u. p. (sp. gr. 922 to 925), placed in well-corked gla.s.s carboys, or stoneware jars or bottles. The maceration is continued, with occasional agitation, for 3, 4, or even 5 weeks, when the aromatised spirit is either distilled or filtered; generally the former. The outer peel of cedrats, lemons, oranges, limettes, bergamottes, &c., is alone used by our Continental neighbours, and is obtained either by carefully peeling the fruit with a knife, or by 'oleo-saccharum,' by rubbing it off with a lump of hard white sugar. Aromatic seeds and woods are bruised by pounding before being submitted to infusion. The substances employed in France to colour liqueurs are, for--blue, soluble Prussian blue, sulphate of indigo (nearly neutralised with chalk), and the juice of blue flowers and berries;--amber, fawn, and brandy colour, burnt sugar or spirit colouring;--green, spinach or parsley leaves (digested in spirit), and mixtures of blue and yellow;--red, powdered cochineal or brazil wood, either alone or mixed with a little alum;--violet, blue violet petals, litmus, or extract of logwood;--purple, the same as violet, only deeper;--yellow, an aqueous infusion of safflower or French berries, and the tinctures of saffron and turmeric.

A frequent cause of failure in the manufacture of liqueurs and cordials is the addition of too much flavouring matter. Persons unaccustomed to the use of strong aromatic essences and essential oils seldom sufficiently estimate their power, and, consequently, are very apt to add too much of them, by which the liqueur is rendered not only disagreeably high flavoured, but, from the excess of oil present, also 'milky,' or 'foul,'

either at once, or, what is nearly as bad, on the addition of water. This source of annoyance, arising entirely from bad manipulation, frequently discourages the tyro, and cuts short his career as a manufacturer. From the viscidity of cordials they are less readily 'fined down' than unsweetened liquor, and often give much trouble to clumsy and inexperienced operators. The most certain way to prevent disappointment in this respect is to use too little rather than too much flavouring; for if the quant.i.ty proves insufficient, it is readily 'brought up' at any time, but the contrary is not effected without some trouble and delay.

A careful attention to the previous remarks will render this branch of the rectifier's art far more perfect and easy of performance than it is at present, and will, in most cases, produce at once a satisfactory article, 'fine, sweet, and pleasant.'

The cordials of respectable British 'compounders' contain fully 3 lbs. of white lump sugar per gallon, and are of the strength of 60 to 64 u. p. The baumes, cremes, and huiles imported from the Continent are richer both in spirit and sugar than ours, and to this may be referred much of their superiority. Mere sweetened or cordialised spirits (eaux, of the Fr.) contain only from 1 to 1-1/2 lb. of sugar per gallon.

The purity of liqueurs is determined in the manner noticed under BRANDY, WINE, &c.

The following list embraces nearly all the cordials and liqueurs, both native and imported, met with in trade in this country:--

=Absinthe.= _Syn._ EXTRAIT D'ABSINTHE DE SUISSE; SWISS EXTRACT OF WORMWOOD. _Prep._ From the tops of _Absinthum majus_, 4 lbs.; tops of _Absinthum minus_, 2 lbs.; angelica root, _Calamus aromaticus_, Chinese aniseed, and leaves of dittany of Crete, of each 15 gr.; brandy or spirit at 12 u. p., 4 galls.; macerate for 10 days, then add water, 1 gall.; distil 4 galls. by a gentle heat, and dissolve in the distilled spirit, of crushed white sugar, 2 lbs. Tonic and stomachic.

=Alker'mes.= This liqueur is highly esteemed in some parts of the South of Europe.

_Prep._ 1. Bay leaves and mace, of each 1 lb.; nutmegs and cinnamon, of each 2 oz.; cloves, 1 oz. (all bruised); cognac brandy, 3-1/2 galls.; macerate for 3 weeks, frequently shaking, then distil over 3 galls., and add of clarified spirit of kermes, 18 lbs.; orange-flower water, 1 pint; mix well, and bottle. This is the original formula for the 'alkermes de Santa Maria Novella,' which is much valued.

2. Spice, as last; British brandy, 4 galls. water, 1 gall.; macerate as before, and draw over 4 galls., to which add, of capillaire, 2 galls., and sweet spirit of nitre, 1/4 pint. Ca.s.sia is often used for cinnamon.

Inferior to the last.

=An'iseed Cordial.= _Prep._ 1. From aniseed, 2 oz. (or essential oil, 1-1/2 dr.), and sugar, 3 lbs. per gall. It should not be weaker than about 45 u. p., as at lower strengths it is impossible to produce a full-flavoured article without its being milky, or liable to become so.

2. (ANISETTE DE BORDEAUX.)--_a._ (Foreign.) Aniseed, 4 oz.; coriander and sweet fennel seeds, of each 1 oz. (bruised); rectified spirit, 1/2 gall.; water, 3 quarts; macerate for 5 or 6 days, then draw over 7 pints, and add of lump sugar, 2-1/2 lbs.

_b._ (English.) Oil of aniseed, 15 drops; oils of ca.s.sia and caraway, of each 6 drops; rub them with a little sugar, and then dissolve it in spirit (45 u. p.), 3 quarts, by well shaking them together; filter, if necessary, and dissolve in the clear liquor sugar, 1-1/2 lb. See PEPPERMINT (_below_).

=Balm of Molucca.= _Prep._ From mace, 1 dr.; cloves, 1/2 oz.; clean spirit (22 u. p.), 1 gall.; infuse for a week in a well-corked carboy or jar, frequently shaking, colour with burnt sugar q. s., and to the clear tincture add of lump sugar, 4-1/2 lbs.; dissolved in pure soft water, 1/2 gall. On the Continent this takes the place of the 'cloves' of the English retailer.

=Bit'ters.= These have generally from 1 to 1-1/2 lb. of sugar per gallon.[19]

[Footnote 19: See article BITTERS.]

=Car'away Cordial.= _Prep._ Generally from the essential oil, with only 2-1/2 lbs. of sugar per gall. 1 fl. dr. of the oil is commonly reckoned equal to 1/4 lb. of the seed. The addition of a very little oil of ca.s.sia, and about half as much of essence of lemon or of orange, improves it. See BRANDY (Caraway).

=Ce'drat Cordial.= _Prep._ From essence (oil) of cedrat, 1/4 oz.; pure spirit (at proof), 1 gall.; dissolve, add of water, 3 pints, agitate well; distil 3 quarts, and add an equal measure of clarified syrup. A delicious liqueur. See CReME and EAU (_below_).

=Cin'namon Cordial.= _Prep._ This is seldom made with cinnamon, owing to its high price, but with either the essential oil or bark of ca.s.sia, with about 2 lbs. of sugar to the gall. It is preferred coloured, and therefore may be very well prepared by simple digestion. The addition of 5 or 6 drops each of essence of lemon and orange peel, with about a spoonful of essence of cardamoms per gall., improves it. 1 oz. of oil of ca.s.sia is considered equal to 8 lbs. of the buds or bark. 1 fl. dr. of the oil is enough for 2-1/2 galls. It is coloured with burnt sugar.

=Cit'ron Cordial.= _Prep._ From the oil or peel, with 3 lbs. of sugar per gall., as above. (See _below_.)

=Citronelle.= _Syn._ EAU DE BARBADES. _Prep._ 1. From fresh orange peel, 2 oz.; fresh lemon peel, 4 oz.; cloves, 1/2 dr.; corianders and cinnamon, of each 1 dr.; proof spirit, 4 pints; digest for 10 days, then add of water, 1 quart, and distil 1/2 gall.; to the distilled essence add of white sugar, 2 lbs., dissolved in water, 1 quart.

2. Essence of orange, 1/2 dr.; essence of lemon, 1 dr.; oil of cloves, and ca.s.sia, of each 10 drops; oil of coriander, 20 drops; spirit (58 o. p.), 5 pints; agitate until dissolved, then add of distilled or clear soft water, 3 pints; well mix, and filter it through blotting paper, if necessary; lastly add of sugar (dissolved), q. s.

=Clairet.= _Syn._ ROSSALIS DES SIN GRAINES. _Prep._ From aniseed, fennel seed, coriander seed, caraway seed, dill seed, and seeds of the candy-carrot (_Athamantia cretensis_--Linn.), of each (bruised) 1 oz.; proof spirit 1/2 gall.; digest for a week, strain, and add of loaf sugar, 1 lb., dissolved in water, q. s.

=Cloves.= _Syn._ CLOVE CORDIAL. _Prep._ From bruised cloves, 1 oz., or essential oil, 1 fl. dr., to every 3 galls. of proof spirit. If distilled, some common salt should be added, and it should be drawn over with a pretty quick fire. It requires fully 3 lbs. of sugar per gall., and is generally coloured with poppy flowers or burnt sugar. The addition of 1 dr. of bruised pimento, or 5 drops of the oil for every oz. of cloves, improves this cordial. See BALM OF MOLUCCA (_above_).

=Coriander Cordial.= _Prep._ From corianders, as the last. A few sliced oranges improve it.

=Creme d'Anis.= As ANISEED CORDIAL, only richer.

=Creme des Barbades.= As CITRONELLE, adding some of the juice of the oranges, and an additional lb. of sugar per gall.

=Creme de Cacao.= _Prep._ Infuse roasted caracca-cacao nuts (cut small), 1 lb., and vanilla, 1/2 oz., in brandy, 1 gall., for 8 days; strain, and add of thick syrup, 3 quarts.