4 10 four hours, which yielded 4 lbs. of crystallized sugar. A maple of ordinary dimensions, in a good year, will yield, on an average, about 198 pints of sap, producing 5 lbs. of sugar. The sap of the maple must therefore contain about 2.2 per cent. of its weight of marketable sugar. It has been found, that with care and attention the maple becomes more productive; maples around which other forest trees have been felled, or which have been transplanted into gardens, yield a sap which is not only more abundant, but also richer in sugar, which, in fact, contains about three per cent. of sugar. The manufacture of maple sugar presents no peculiarity; precisely the same process is followed as in the case of the cane and beet. Unless very speedily boiled down, the sap ferments, and undergoes change; in some parts of the United States, indeed, a vinous liquor is made of the sap, by allowing it to run into spontaneous fermentation. PALM SUGAR. The palm which in the southern parts of India furnishes crystallized sugar in large quantity, is the cleophora of Gaertner, and reaches a height of about 100 feet. Its fruit hangs in clusters upwards of a yard in length. The natives procure the sap by cutting short one of the shoots that is about to flower and carry fruit, and hanging under the cut part of a calabash or other vessel, into which the fluid distils; in a large plantation such an apparatus is seen connected with each palm-tree; the sap is removed every morning, and it is enough to reduce it by evaporation to obtain the sugar, which differs in no respect from the finest sugar of the cane; in the unrefined state it is known over the whole of the East under the name of jaggery,* and is then a kind of moist and sticky muscovado sugar. The sap of the palm-tree obtained in the way above indicated, is often turned into a vinous liquor, which is much prized in many places. The pith of the tree yields sago. The palm-trees cultivated in India consequently yield three most useful products— sugar, oil, and the farinaceous article of diet called sago. In rearing the cocoa-nut palm, those nuts are selected for seed which fall naturally, and they are dried in their husk. The ground which is to be sown is dug to a depth of eighteen or twenty inches, and it is left to settle for three or four days. Some portion of the surface is then taken away, and the fresh soil is covered, to the depth of about six inches, with sand. The nuts are then placed upon the ground so prepared, and covered over with a little sand and a light stratum of vegetable mould; they are then watered for three days consecutively. In the course of three months the young palms are fit to be transplanted, and they are set at the distance of about twenty feet every way from one another. For their reception in the permanent *This is the generic name for sugar, and is obviously either the Latin word saccharum, or from the same root as the Latin word. The cocoa-nut tree treated in the same way as the cleophora yields abundance of sugar, which is also known under the name of jaggery.-ENG. ED. plantation, holes are dug of about two feet in depth, in which a layer of sand, about six inches in depth, is put, upon which the young plants, still adhering to the fruit, are placed; the hole is then filled with sand, and the surface is covered with a little earth. The young trees require watering every day during about three years. The palm begins to be productive at the age of seven or eight years, and it continues to yield fruit, or sap for the manufacture of sugar, during a very considerable period, without causing any further cost for cultivation.* The sap of the greater number of the palms appears to be rich in saccharine matter; it is obvious, indeed, that every sap that is capable of supplying a vinous liquor by fermentation, may also furnish sugar; and if the palms have not generally been grown with a view to this product, it is because the fruit must then be given up, and, both in India and South America, the produce in the shape of oil from the nuts of the palm, is almost always more valuable than that which can be had in the shape of sugar.† GRAPE SUGAR. We have already said that starch acted upon by acids, and by malted barley, is changed into a saccharine fermentable substance, which, both in regard to flavor and physical properties, differs in many respects from the sugar which we have hitherto been engaged in studying. As this substance exists naturally in the grape, it has been called grape sugar, a name for which the generic term glucose has been lately substituted in France, this term being used to include all the sugars that are analogous to grape sugar. Grape sugar occurs in the form of small white and very soft crystals, grouped in tubercular masses; it softens at 60°, (140° Fahr.,) and becomes quite sirupy at 90°, (194° Fahr.) Alcohol free from water dissolves none of it; but diluted alcohol takes up a considerable quantity. In the grape this sugar is associated with cream of tartar, tartrate of lime, and several other saline matters. It is easily extracted from the fruit; but the grape sugar of commerce is now universally prepared from starch; large quantities, indeed, are manufactured on the continent for the preparation of spirit, and for the amelioration of wine, beer, cider, &c., in short, to supply sugar wherever it is defective in the natural or artificial musts that are subjected to fermentation. In England considerable quantities are also manufactured; but here the law does not allow it to be used in the same advantageous direction as in France and Germany; all that is made is employed for mixing with adulterating cane sugar, which is an article of higher price. The sugar that is made from starch, and that is obtained from the grape are identical in composition, as is that also which is found in the urine of persons laboring under diabetes. * Buchanan. A Journey from Madras, &c., vol. i. p. 155. † In British India the cocoa-nut palm is beginning to be extensively cultivated as a means of producing sugar. A considerable portion of the East India sugar now brought to market, is manufactured from the palm-tree. It is not improbable, indeed, that the palm of one species or another will one day supersede the sugar-cane and the beet as the source of all the sugar consumed in Europe.-ENG. ED. Like cane sugar, grape sugar in combining with certain bases bandons a portion of its constitutional water. In the state in which t is combined with the oxide of lead it contains From these analyses it appears that crystallized grape sugar consists of On comparing the two kinds of sugar in the crystallized state, it becomes evident that glucose or grape sugar does not differ from cane sugar, except in containing a larger quantity of water. In fact the composition of grape sugar may be represented in this way: The cane, the beet, the palm, the maple, the vine, and starch, turned into glucose, are the sources from whence all the sugar of commerce is obtained at the present day, although attempts more or less successful have also been made to extract sugar from the pineapple, from the chestnut, from the sweet orange, and from the stem of the maize or Indian corn. It appears that before the conquest the Mexicans prepared a sirup from the stem of the Indian corn, which was sold in the market-places. Pallas could not obtain more than about 3 per cent. of crystallized sugar from maize, but in an experiment which I made in South America along with M. Roulin, the quantity of raw sugar obtained from this plant was 6 per cent. SACCHARINE PRINCIPLES NOT FERMENTABLE. Manna; mannite. This saccharine principle is met with in different plants; it has been found in the expressed juice of onions, and in that of asparagus, in the alburnum of several species of pinetrees, and in different mushrooms. Manna, which is an exudation from the fraxinus ornus and larch, contains nearly 4ths of its weight of mannite, and it is therefore from this substance that mannite is usually obtained, although it can also be had from the juice of the beet and the onion; but then it is necessary to destroy the cane or grape sugar which they contain by previous vinous fermentation, J and M. Pelouze has even maintained that the mannite thus prepared is a product of fermentation.* Mannite crystallizes in very white semi-transparent needles; it has a slightly sweet taste, and is soluble in water. According to Liebig and Opperman it contains : Liquorice. This substance, which is obtained from the root of the Glycirrhiza glabra, is too well known to require particular consideration; it is soluble both in water and in alcohol. GUM. Gum is a substance very extensively diffused in the vegetable kingdom; there is, perhaps, no plant which does not contain some. Gum is divided into two kinds; gum, properly so called, the type of which we have in gum-arabic, and vegetable mucilage, such as we meet in gum-tragacanth. Gum in dissolving in water produces a thick and adhesive fluid. It is insoluble in alcohol. Some plants contain such a quantity that upon infusion they seem to give, as it were, nothing else: such are the althea, the malva officinalis, &c. Gum does not crystallize, it is met with in concrete masses which result from the solidification of the drops which flow spontaneously from the trees that yield it: by long boiling with dilute sulphuric acid it is changed into glucose. Nitric acid alters it, and several new products are the result, among the number of which is mucic acid. Gum-arabic, according to the analysis of M. Gay-Lussac and Thénard, consists of: To obtain vegetable mucilage, a quantity of linseed is treated with water and expressed. It is also obtained by steeping gum tragacanth in about 1000 parts of water and pouring off the solution which covers the mucilaginous mass. The mucilage then forms a jelly more or less consistent, which diluted with a large quantity of water forms a ropy viscid fluid. Dried again, this mucilage becomes hard and translucid; in water it regains its former state.† VEGETABLE JELLY-PECTINE AND PECTIC ACID. It is well known that the juice of all fruits contains a gelatinous substance to which many of them owe the property of forming jellies. * Annales de Chimie, vol. xlvii. p. 419, 2d series.-The refuse wash of the distiller, appreciated by the taste, appears to contain a considerable quantity of saccharine matter, which is probably mannite.-ENG. ED. + Berzelius, Chemistry, vol. v. This matter may be obtained by means of alcohol. If into a quantity of currant juice lately expressed, a portion of alcohol be poured, a gelatinous precipitate is formed after a certain time; this jelly, subjected to graduated pressure and washed with diluted alcohol, gives the gelatinous principle in a state of tolerable purity: this is pectine, discovered by M. Braconnot. Pectine dried is in membranous semi-transparent pieces resembling isinglass. Thrown into about one hundred times its weight of water it swells considerably and at length dissolves completely, giving rise to a stiff jelly. By increasing the quantity of water, a mucilaginous solution, having a slightly milky aspect, is obtained. Pure pectine is quite insipid; it does not affect the color of litmus, the weaker acids have no effect upon it; a slight excess of potash or of soda does not change it obviously, and nevertheless pectine is singularly modified under the influence of these alkalies, being changed into a particular body, having acid reaction; for on saturating the alkali employed, it immediately coagulates into a transparent gelatinous mass-pectic acid. As pectine acted upon by the fixed alkalies undergoes so remarkable a change, we may be allowed to conclude, with M. Braconnot, that the pectic acid which is found ready formed in plants, has a similar origin; a view moreover which tends to confirm that formerly announced by Vauquelin, when he ascribed the development of the acids of vegetables to the presence of alkalies.* Gelatinous pectic acid immediately becomes defluent upon the addition of a few drops of solution of ammonia. By evaporating this solution in a porcelain dish we obtain an acid pectate of ammonia, which swells in distilled water, dissolves in it, and thickens a large quantity of the fluid. As ammonia has no reaction upon pectine, M. Braconnot has taken advantage of this negative property to determine if pectic acid exists or not, ready formed, in certain plants. Thus in treating carrots with cold water, rendered slightly ammoniacal, a liquid is obtained, from which an acid immediately throws down a precipitate of pectic acid.† Pectine and pectic acid, therefore, may exist together in vegetables, and M. Jacquelain has proved that the acid there is often in a state of combination as an alkaline or earthy pectate. It is to these pectates that M. Payen ascribes the origin of the carbonates of the same bases, which are met with in the ashes of plants, the organic acid having of course been destroyed by the combustion.‡ M. Braconnot has described an easy process for obtaining pectic acid in large quantity from carrots.§ M. Fremy has published analyses of pectine and pectic acid, which present this remarkable peculiarity, that the ne has exactly the same elementary composition as the other. * Braconnot, Annals of Chemistry, vol. xlvii. p. 274, † Braconnot, op. cit. vol. xxx. p. 99. series Payen, Proceedings of the Academy of Sciences, vol. xv. p. 907 |