Cooley's Cyclopaedia of Practical Receipts Volume Ii Part 239

=SUC'CORY.= Chicory, or wild endive. (See CHICORY.)

=SUDORIF'ICS.= See DIAPh.o.r.eTICS.

=SU'ET.= _Syn._ SEVUM, SEb.u.m, L. This is prepared from the fat of the loins of the sheep or bullock by melting it by a gentle heat, and straining the liquid fat. In this state it forms the ADEPS OVILLUS (Ph.

D.), SEVUM (Ph. L. & E.), SEVUM OVILLUM, or SEVUM PRaePARATUM, employed in medicine and perfumery, as the basis of ointments, cerates, plasters, pommades, &c.

=Suet, Mel'ilot.= _Syn._ SEVUM MELILOTI, L. _Prep._ From suet, 8 lb.; melilot leaves, 2 lb.; boil until the leaves are crisp, strain, and allow it to cool very slowly, so that it may 'grain well.' Used by farriers, and to make melilot plaster.

=SUFFOCA'TION.= The treatment varies with the cause. See ASPHYXIA, CHARCOAL, DROWNING, HANGING, SULPHURETTED HYDROGEN, &c.

=SUG'AR.= C_{12}H_{22}O_{11}. _Syn._ CANE SUGAR; SACCHARUM, L.; SUCRE, Fr.

This well-known and most useful substance is found in the juice of many of the canes or gra.s.ses, in the sap of several forest trees, and in the roots of various plants. In tropical climates it is extracted from the sugar-cane (_Saccharum officinarum_), in China from the sweet sorgho (_Sorghum saccharatum_), in North America from the sugar-maple (_Acer saccharinum_), and in France, Germany, Russia, and Belgium, from white beet-root (_Beta vulgaris_, var. _alba_).

Until of late years the ordinary sugar consumed in this country was that chiefly sent from the West Indian Islands, South America, the Mauritius, &c., and was the produce of the sugar cane; recently, however, large and increasing quant.i.ties of beet-root sugar have found their way into the English markets from the Continental factories.

The _Saccharum officinarum_, of which there are several varieties, the sugar-cane ranges in height from 6 to 15 feet, and in diameter from 1 to 2 inches. In order to obtain the saccharine juice contained in it, the cane, stripped of its leaves, is cut just before the commencement of inflorescence, the period in which it is richest in juice. As this sap or juice is found to abound most in sugar, when taken from the lower part of the stem, the cane is cut off nearly close to the ground.

The stump which remains develops into a fresh plant, and one plant thus treated will last several years, not, however, without a gradual diminution in the size of the successive crops.

In South America and the West Indies a variety known as the Otaheita cane is extensively cultivated, since it is very productive and yields a large amount of juice.

The annual average produce in raw sugar for a hectare (about 2-1/4 English statute acres) of land is in

Martinique 2000 kilos.[201]

Guadaloupe 3400 "

Mauritius 4000 "

Brazil 6000 "

[Footnote 201: A kilo = 22046 lbs.]

Sugar-cane growing in the below-mentioned places has, according to the a.n.a.lysis of the three chemists whose names are appended, the following composition:--

(_a._) (_b._) (_c._) Peligot. Dupuy. Icery.

Sugar 180 178 200 Water 721 720 690 Cellulose 99 98 100 Salts -- 04 07-12

The cane, therefore, may be said to yield 90 per cent. of juice, which latter contains from 18 to 20 parts of pure sugar. However, the actual quant.i.ty obtained is rarely if ever more than 1 lb. of sugar to a gallon of juice, or 10 per cent.; and much more frequently only 8 per cent.

A large part of this loss is due to the prolonged exposure of the cane juice during its repeated boilings to heat, whereby a large proportion of its crystallisable sugar is converted into the uncrystallisable variety which pa.s.ses away in the form of mola.s.ses and treacle. Another important cause of loss is the retention of a large amount of juice by the cane.

The following figures will convey an idea of the enormous quant.i.ties of cane sugar produced and consumed yearly throughout the globe. It is taken from 'British Manufacturing Industries,' one of a series of excellent industrial manuals published by Mr Sandford, of Charing Cross:--

Cuba 600,000 tons.

The other West Indian colonies 250,000 "

Java and Sumatra 170,000 "

China 140,000 "

French colonies in America and Africa 120,000 "

Brazil 100,000 "

Mauritius 80,000 "

British Guiana 80,000 "

Porto Rico 90,000 "

Manilla 60,000 "

Mexico 35,000 "

Egypt Large and growing.

The late Dr Edward Smith found that 98 per cent. of indoor operatives partook of 7-1/2 oz. of sugar per adult weekly; that 96 per cent. of Scotch labourers use it; and 80 per cent. of Irish. He further states that in Wales sugar is commonly used to an average extent of 6 oz. per adult weekly; but that there is a marked difference in the rate of consumption in the northern and southern portions of the princ.i.p.ality. In North Wales, for example, the average amount per head is 11-1/4 oz.; whereas in South Wales it is only 3 oz.

The manufacture of sugar is exclusively conducted on the large scale. The recent canes are crushed between rollers, and the expressed juice is suffered to flow into a suitable vessel, where it is slowly heated to nearly the boiling-point, to coagulate alb.u.minous matter. The crushed canes generally supply the fuel needed for this purpose. The ashes left after the combustion of the canes are carefully collected and used as a manure for future crops of sugar cane.

The cut below represents a press for the extraction of the juice from the canes. By means of the screws (_i i_), the rollers are adjusted to the proper distance apart; the upper roller is half the size of the two lower ones, and all are moved by cogged wheels fitting on to the axes of the rollers. The sugar-canes are transferred from the slate gutter (_d d_) to the rollers (_a c_), which press them a little; and from thence they are carried over the arched plate (_n_) to the rollers (_c b_). The pressed sugar-canes fall over the gutter (_f_), the expressed juice collecting in _g g_, and running off through _h_. A small quant.i.ty of milk of lime is then added to the juice to remove mechanical impurities, and the skimmed and clarified juice, after being sufficiently concentrated by rapid evaporation in open pans, is transferred to coolers, and thence into upright casks perforated at the bottom, and so placed that the syrup, or uncrystallisable portion, may drain off into a tank or cistern from the newly formed sugar. During the period of crystallisation it is frequently agitated, in order to hasten the change, and to prevent the formation of large crystals. The solid portion of the product forms moist, raw, or muscovado sugar; the uncrystallisable syrup, mola.s.ses or treacle.[202]

[Footnote 202: The term 'mola.s.ses' is usually restricted to the drainings from raw sugar, and 'treacle' to the thicker syrup which has drained from refined sugar in the moulds.]

[Ill.u.s.tration]

Raw sugar is refined by redissolving it in water, adding to the solution alb.u.men, under the form of serum of blood or white of egg, and, sometimes, a little lime-water, and heating the whole to the boiling-point; the impurities are then removed by careful skimming, and the syrup is decoloured by filtration through recently burnt animal charcoal; the clear decolorised syrup is next evaporated to the crystallising-point in vacuo, and at once transferred into conical earthern moulds, where it solidifies, after some time, to a confusedly crystallised ma.s.s; this, when drained, washed with a little clean syrup, and dried in a stove, const.i.tutes ordinary loaf, lump, or refined sugar. Sometimes in washing the crystallised ma.s.s for the purpose of removing the coloured syrup which is mingled with it, the process known as 'claying' is followed.

In this case, instead of white syrup being used, a layer of thin mud or a paste of thin pipe-clay is poured into the mould on to the base of the inverted sugar cone, through which the water escaping from the mud or pipe-clay permeates, and carries with it the coloured syrup. Neither the mud nor the pipe-clay mix with the sugar, but remaining on the top soon become hard, when they are removed. As the syrup running from the moulds still contains a large quant.i.ty of crystalline cane sugar, this is recovered as follows:

The syrup, after being sufficiently concentrated by boiling in the vacuum pan, is removed and allowed to cool, when it a.s.sumes the appearance of a crystalline magma known as 'crushed sugar.'

Crushed sugar is a mixture of a large quant.i.ty of sugar crystals with uncrystallisable syrup. To get rid of this latter from the crystals, the ma.s.s is placed in quant.i.ties of 3 or 4 cwts. at a time in a 'centrifugal machine.' This, of which an engraving is given below, consists, as will be seen, of a drum fixed on a vertical axis. The walls of the drum are made of perforated metal, or are formed of meshed wire work, and the drum itself enclosed in an outer metal cylinder, which is fixed, and, of course, unperforated. When the drum is made to revolve on its axis at the rate of 1000 or 1200 revolutions in a minute, the syrup flying off by centrifugal action, and escaping through the perforation at the sides of the drum, is received into the outer cylinder, whence it escapes by a trough into a proper receptacle, leaving behind the crystals in the interior of the drum.

[Ill.u.s.tration]

_a_ is an open drum of fine meshed wirework, caused to revolve in the cast-iron vessel (_b b_), by means of the bevel wheels (_c d_), gearing with a motive power. The motion of the drum can be stopped by means of the brake (_e_), and regulated by the weights placed at _o_.

When the crystallisation of sugar is allowed to take place quietly and slowly, the product is sugar candy. The evaporation at a low temperature in vacuum pans has the effect of diminishing the yield of treacle.

_Prop._ Sugar requires for its solution only 1/3rd of its weight of cold and still less of boiling water; it is slowly dissolved by cold rectified spirit; it dissolves in 4 parts of boiling rectified spirit and in 80 parts of boiling absolute alcohol; it melts by heat, and cools to a gla.s.sy amorphous ma.s.s (barley sugar); at about 400 Fahr. it suffers rapid decomposition, and fuses to a brown, uncrystallisable ma.s.s (caramel); long boiling with water increases its colour, and lessens its tendency to crystallise; its aqueous solution dissolves alkalies, earths, and many metallic oxides, with facility. The presence of cane sugar in solutions containing certain metallic salts prevents the precipitation of their oxides by alkalies. The oxides of copper and iron are amongst those thus kept in solution. Sugar also possesses the power of effecting the partial or complete reduction of many metallic oxides, if boiled with their salts; the first results is exemplified in the case of the chromates; for if a chromate be added to a solution of sugar, and to the mixture a few drops of free acid, the chromic acid suffers reduction to chromic oxide, which, dissolving in the excess of acid, imparts a green colour to the liquid.

Mercuric salts become reduced to mercurous, whilst the salts of gold throw down a precipitate of the metal in fine powder. The action of strong oil of vitriol on cane sugar is very energetic. The sugar is instantly reduced to a black charred ma.s.s, whilst carbonic and formic acids are given off.

The same effects are produced by exposing it to dry chlorine at a temperature of 212 F. By nitric acid of sp. gr. 125, cane sugar is converted into saccharic acid; if a stronger acid be employed, oxalic acid is produced. When a mixture of concentrated nitric and sulphuric acids is poured on to cane sugar, an explosive compound, resembling gun cotton, is produced. This body is known as 'nitro-sugar.' Weak syrups take up about half as much hydrate of calcium as they contain sugar; when slowly crystallised, it a.s.sumes the form of oblique 4-sided prisms, terminated by 2-sided summits. Sp. gr. 160 (1577--Ure).

_Pur._ Moist or muscovado sugar and crushed lump sugar are occasionally adulterated with chalk, plaster, sand, potato-flour, and other fecula; but frequently, and in certain neighbourhoods constantly, with starch sugar or potato-sugar.[203] These frauds may be detected as follows:

[Footnote 203: See further on.]

_Tests._--1. Pure cane sugar dissolves freely and entirely in both water and proof spirit, forming transparent colourless solutions, which are unaffected by either sulphuretted hydrogen or dilute sulphuric acid.--2.

Its solution bends the luminous rays in circ.u.mpolarisation to the right, whereas grape and fecula sugars bend it to the left.[204]--3.

(Chevallier.) Boiled for a short time in water containing 2 or 3% of caustic pota.s.sa, the liquid remains colourless; but it turns brown, which is more or less intense, according to the quant.i.ty, if starch sugar is present. Even 2 or 3% of starch sugar may be thus detected.--4. (E.

Krantz.) A filtered solution of 33 gr. of cane or beet sugar in 1 fl. oz.

of water, mixed with 3 gr. of pure hydrate of pota.s.sium, and then agitated with 1-1/2 gr. of sulphate of copper in an air-tight bottle, remains clear, even after the lapse of several days; but if starch sugar be present, a red precipitate is formed after some time; and if it is present in considerable quant.i.ty, the copper will be wholly converted into oxide within 24 hours, the solution turning first blue or green, and then entirely losing its colour.--5. (Trommer's test.) A solution of cane sugar is mixed with a solution of sulphate of copper, and hydrate of pota.s.sium added in excess; a blue liquid is obtained, which, on being heated, is at first but little altered; a small quant.i.ty of red powder falls after a time, but the liquid long retains its blue tint. When grape sugar or fecula sugar is thus treated, the first application of heat throws down a copious greenish precipitate, which rapidly changes to scarlet, and eventually to dark red, leaving a nearly colourless solution. This is an excellent test for distinguishing the two varieties of sugar, or discovering an admixture of grape sugar with cane sugar. The 1/1000th part of grape sugar may be thus detected. The proportion of oxide of copper produced affords a good criterion, not only of the purity of the sugar, but also of the extent of the adulteration.--6. (Ure.) Dissolve a little sulphate of copper (say 20 gr.) in a measured quant.i.ty of water, and add to it, in the cold, a solution of hydrate of pota.s.sium, until, by testing with turmeric paper, the liquid appears faintly alkaline, shown by the paper becoming slightly brown. If a small quant.i.ty of this test-liquor (previously well shaken) be added to an aqueous solution of the sugar, and the whole boiled, the solution becomes at first green, and then olive-green, if dextrin is present; but if it contain grape sugar, the salt of copper is immediately reduced into the state of orange and oxide; whilst a solution of pure sugar undergoes no change, or is scarcely altered.--7. M. Riffard,[205] taking advantage of the fact that sugar, like tartaric, malic, citric acid, and alb.u.men, prevents the precipitation of iron by ammonia, employs iron as a means for estimating sugar. A solution containing sugar and iron in a certain proportion, when saturated with ammonia, will form a compound of a fine red colour, which remains clear if no alkaline earthy metals are present. M. Riffard has applied to sugar the method proposed by M. Juette for the estimation of tartaric acid. He observed that a neutral or acid solution of crystallised perchloride of iron, when heated for a considerable time to 100 C, requires 2710 grams of sugar, if 100 milligrams of iron are to remain in solution in the presence of ammonia. If, on the other hand, the solution is prepared simply by dissolving crystallised perchloride of iron in pure water, without the addition of an acid, 100 milligrams of iron only require 2587 grammes of sugar to remain dissolved. In this case the liquid is perfectly clear, and remains so; but if a smaller quant.i.ty of sugar be added, it is turbid, and deposits peroxide of iron. To estimate the sugar by this process, 25870 grammes of the substance to be tested are dissolved, the solution mixed with a few drops of oxalate of ammonia to precipitate the lime, filtered and made up with water to 250 c.c., 25 c.c. of this mixture require the addition of as many milligrams of iron as there are per cents. of pure sugar in the sample under examination, and by two tests the following results will be arrived at:--With _n_ milligrams of iron the solution is clear. With _n_ + 1 milligrams of iron the solution is precipitated. _n_ representing the number of per cents. of sugar contained in the sample.--8. M. Perrot's method for the determination of sugars by means of normal solutions is as follows:--He prepares a standard solution of copper by dissolving 39275 grams of sulphate of copper, very pure, and dried between several folds of filtering paper, and makes it up with distilled water to 1000 c.c. Each c.c. of this solution contains 001 grams of copper. On the other hand, he dissolves about 25 grams of pure cyanide of pota.s.sium in 1 litre of distilled water. Of this solution 10 c.c. are taken and put in a flask, to which about 20 c.c. of ammonia are added, and the liquid is kept at a temperature of 60 or 70. He pours in the copper solution drop by drop by means of a burette graduated into tenths of a c.c., until there appears the blue tint characteristic of salts of copper in an ammoniacal solution.

The number of degrees of the burette are then read off, and indicate the quant.i.ty of copper which has been required to produce the reaction. The solution of the sugar in question (previously inverted if it is required to determine crystalline sugar) is then placed in contact with an excess of Fehling's liquor, and reduced in the water-bath. The whole is filtered in order to collect the precipitate of suboxide, which is first well washed with hot water, and dissolved in nitric acid, diluted with an equal volume of water, and a few fragments of chlorate of pota.s.sa are added.

This solution is effected on the filter, which is then carefully washed in acidulated water. The filtrate to which the washings are added is then mixed with water enough to make up 100 or 150 c.c., and is then poured by means of the burette into 10 c.c. of cyanide, mixed with 20 c.c. of ammonia as above, stopping when the blue colour appears, and reading off the quant.i.ty of copper employed. From the former experiment it is known how much copper 10 c.c. of the cyanide solution require. Hence it is easy to calculate the total amount of copper which has been present as suboxide. The amount of sugar is then found from the data that 9298 parts of copper equal 5000 of crystalline sugar, or 5263 of glucose.[206]--9.

The specific gravities and crystalline forms offer other means of distinguishing the varieties of sugar.

[Footnote 204: Of late years, owing to the little difference in price between the two, this form of adulteration has been abandoned.--ED.]