The London Journal of Arts, Sciences, and Manufactures, and Repertory of Patent Inventions.
Conducted by Mr. W. Newton, of the Office for Patents, Chancery Lane. (Assisted by several Scientific Gentlemen.)
VOL. XXXVI. (Conjoined Series.)
London: Published by W. Newton, at the office for patents, 66, Chancerylane, and Manchester; t. and W. Piper, Paternoster Row; Simpkin, Marshall, and Co., Stationers' Court; J. McCombe, Buchanan St., Glasgow; and Galinani's Library, Rue Vivienne,
Paris. 1850
No. CCXXI.By M. W. Stein, of Dresden.
[Translated for the London Journal of Art s and Sciences.]
Towards the close of last year a substance, bearing the name of Wongshy, was imported from Batavia into Hamburgh, with the view of being employed as a yellow dye. As no account has yet been published, relative to the application of this substance to the purpose of dyeing, the following particulars may, perhaps, prove interesting.
The new coloring matter consists of pods of seed, obtained from a plant, which, according to M. Reichenbach, belongs to the gentian family. The pods, which are unilocular, jure of an oblong form, ovoidal, and terminating in a point on that side near the []obtuse at the opposite extremity, and surrounded by the calix, which is dry and has five divisions. They vary in size, which is generally from 1 J to 1 J inches in length, with a diameter (in the largest part) of about half an inch. The color is a reddish-yellow, which is not uniform; it being darker in some places than others. The surface is more or less irregular and wavy, with from six to eight longitudinal nerves. It has a smell somewhat like saffron, with an after smell of honey. The shell is hard and brittle, and on being masticated it quickly becomes mucilaginous and colors the saliva yellow, giving out a slightly bitter flavor. It swells considerably in water. Inside the pods are small seeds, of a deep reddish color, and having a rough surface; they are detached from the sides, and are closely imbedded in a hard pulp: as many as 108 of these seeds have been counted in one pod. These seeds are rather hard, being chewed with difficulty, and having no particular flavor; but leaving on the end of the tongue a peculiar burning sensation, sweet and stinging, which is similar to that of red paraguay: the pulp in which they are imbedded has a strong bitter taste, which is most perceptible at the back of the gums.
The embryo, which consists of cells, containing amylum, is surrounded with albumen; the amylum may be easily detected by means of iodine, which partially colors the embryo blue, but does not affect the mass surrounding it. On being properly prepared and viewed under the microscope, this embryo presents two cotyledons; and its structure is more particularly seen on making a transverse section of the seeds passing through the em bryo. It is also to be remarked that the amorphous coloring matter, which is yellow in the cells inside the pod, with a slight tinge of green, appears of a purple red in those placed outside.
The wongshy fruits (when ground, both at the ordinary temperature, and at the boiling point) give up to water their coloring matter, which is of so divisible a nature, that two parts of the ground pods furnish 1 28 parts of a liquor which, on being intro duced into a cylindrical vessel of white glass, 2^- inches in diameter, displays, when exposed to the light, a clear yellow color. The concentrated extract is very mucilaginous, and is of a fire-red color, which disappears when the liquor is much diluted, and is converted into a gold-yellow. Alcohol, at 80° Centigrade, and also pure alcohol, on digesting pulverized fruit in it, also acquires a fire-red color, which is, by dilution, converted into gold-yellow. On digesting it in ether, it is, at the ordinary temperature, colored variously from pale up to brownish-yellow, and leaves, after evaporation, a thick yellowish-brown oil, which has a fruity smell and a sweet taste, slightly bitter; and which at 0° only deposits a small quantity of concrete fatty matter: on being agitated with azotate of protoxide of mercury, it does not thicken, even after a length of time; and consequently may be classed amongst the siccative oils. By saponification, perfectly colorless fatty acids may be extracted from it. The color of this oil is therefore due to a small quantity of the coloring matter which it has carried off with it.
Fatty oils do not possess the property of extracting any portion of coloring matter from these fruits, either at the ordinary temperature, or with the addition of heat.
An aqueous solution is obtained, in the form of jelly, by the addition of alcohol. This jelly, which is of a yellowish color, may be rendered perfectly colorless by washing with alcohol. On drying, it forms a translucid mass, which is slowly dissolved by water,—forming a thick mucilage. (In one experiment made by M. Stein, in which it was extracted from a fermented solution of the coloring matter, it was not obtained in the gelatinous form, but in the form of soft flakes, which, after drying, remained white and opaque, but otherwise behaved in the same maimer as the translucid substance.) This solution is not precipitated by acids; caustic soda, in excess, produces a gelatinous deposit; and when the soda is only in small quantity, the liquor remains limpid; but the addition of acid immediately produces gelatinous flakes. Carbonate of potash behaves in the same manner,—excepting that a considerable time is required for the production, by an excess of that salt, of the gelatinous thickening of the liquor, and that acids only produce slight flakes. Water of baryta precipitates the solution so completely, that the liquor from which the precipitate has been separated by filtration, on being submitted to evaporation upon a sheet of platina, and the residuum calcined, presents no traces of organic matter.—Lime water also produces an analogous precipitate, and acetate of lead produces a gelatinous precipitate.
The manner in which this substance behaves, and which has just been mentioned, agrees with the properties of pectine, as described in a recent work of M. Fremy; it will therefore be seen that wongshy contains a considerable quantity of pectine.
If, after having deprived the liquor of pectine by means of alcohol, a small quantity of acetate of copper be added, and caustic soda in excess, protoxide of copper will be precipitated. This substance, therefore, contains sugar, the presence of which is also manifested by the fact, that on exposing it in a pulverized state, and diluted with water, to a moderate heat, alcoholic fermentation will take place. During this fermentation, which, in one experiment, lasted more than three weeks, carbonic acid was disen gaged in large quantity, together with, at first, an odour of beer, which afterwards changed to that of butyric and valeric acids. On afterwards submitting the fermented liquor to distillation, a product was obtained which did not contain any alcohol, but only traces of acetic and butyric acids. In the liquor which remained, neither lactic acid nor mannite was detected. These phenomena of fermentation differ materially from those presented oy what is called viscous fermentation; by which, as is known, sugar is decomposed into carbonic acid, gum, lactic acid, and maunite, without the formation of alcohol.
* One experiment made by M. Stein, for the purpose of ascertaining whether with alum, and by precipitating with potash, a fine lacker might not be produced, did not give satisfactory results; as by this means only a small portion of the coloring matter, combined with the alumina, was precipitated, which was entirely removed hf simple washing with water.A solution of gelatine produces in the aqueous extract a trace of precipitate, arising from the presence of tannin. Chloride of tin, at the ordinary temperature, does not, even after the lapse of considerable time, produce any change; but, on raising the temperature, a precipitate of a deep orange color is perceptible. Basic acetate of lead produces no change. Simple acetate of lead produces a slight cloudiness at the ordinary temperature, and an orange precipitate at the boiling point. Sulphate of iron changes the color to a deep brown-yellow, without any precipitate being formed, either in the hot or cold state. Alum,* acetate of alumina, and acetate of zinc, give yellow precipitates, but only in the hot state. Baryta water, even at the ordinary temperature, produces a yellow precipitate, which, on being boiled, turns to a reddish tint. Lime water furnishes a yellow precipitate, which is not changed by heat, Solutions of sulphate of lime and chloride of calcium give no precipitate, either in the hot or cold state. Spring water, containing a considerable quantity of car bonate of lime, did not precipitate the coloring matter, even with the addition of heat; this latter is, therefore, unable to decompose combinations of lime with acids.
With regard to the solution of the coloring matter when completely deprived of pectine, water of baryta and of lime act rather differently,—as orange precipitates are formed at the boiling point. Caustic soda, caustic ammonia, and carbonate of potash render the color darker and tinge it brown. This change is not due to the coloring matter itself, but results from the action of the alkalies upon the sugar of gelatine which is present; and also upon a very bitter and easily changed substance which could not be separated. At the same time, on boiling the liquor and employing carbonate of potash or caustic soda, the disengagement of ammonia will be perceived on testing it by holding litmuspaper over the mouth of the vessel Nitric acid, in small quantity, and at the ordinary temperature, does not produce any change in the liquor; but when this acid is added in larger quantity, it causes the red color of the liquor to disappear; which then appears limpid, although slightly tinged with red. Each drop of acid, on falling into this liquor, causes it to assume a greenish tint, giving to the matter a distant resemblance to saffron yellow, which is also turned green by nitric acid. Sulphuric acid of commerce, in the cold state, produces a brown-yellow, and in the warm it is a yellowish-green by transmission, and a deep green by reflection. After the lapse of some time, olive-green flakes are separated, whilst the liquor appears of a reddishbrown color. Hydrochloric acid does not produce any change in the liquor at the ordinary temperature; but, on being heated, and before reaching the boiling point, it appears of a yellow-green color by transmission and deep green by reflection. Soon afterwards deep green flakes are precipitated, and the liquor becomes of a reddish-brown color. This reaction, which distinguishes the extract of wongshy from solutions of all other known yellow coloring substances, is not caused by the pure coloring matter, but by the bitter substance above mentioned; and for this reason this test must not be employed for ascertaining whether fabrics have been dyed with wongshy, as the bitter substance does not combine with the fabric. Tartaric and citric acids change the color to a brown-red. Metallic zinc, with the addition of a few drops of hydrochloric acid, decolors the liquor, changing it to a pale yellow, which colors woollens but very slightly. The liquor does not recover its former color on exposure to the air. Sulphurous and hydros ulph uric acids only produce imperfect decoloration of the liquid;—complete decoloration is obtained with difficulty, even by the action of chlorated water.
In order to ascertain with certainty whether wongshy could be employed for dyeing, M. Stein infused a quantity of the pulverized pods in lukewarm water for twelve hours—stirring frequently; after which, the liquor was run off. In this manner the coloring matter was extracted in the most expeditious manner, without the liquor becoming too thick or viscous, by the formation of paste, which would take place at the boiling point.
M. Stein states that, notwithstanding many experiments, he has not been able to produce a good green with wongshy yellow.With this extract, samples of woollens, properly prepared, were dyed, some without mordant, and others mordanted with alum, chloride of tin, acetate of alumina, and acetate of lead, in a bath heated to about 50° Centigrade, —as at a higher temperature the color is not pure.* The result was, that the unmordanted stuff was dyed, in a single bath, of a fine uniform orange color; and that amongst the mordanted samples, those treated with alum and acetate of alumina were better than those treated with chloride of tin; and that those having acetate of lead for a mordant, produced the least satisfactory results. The tone of the color was not changed by the three first-mentioned mordants; the samples were, however, dyed with a color less intense and less uniform. By means of a second bath, the samples treated with alum gave perfectly satisfactory results.
The coloring matter combines as readily with silk, and communicates to it a very brilliant gold color; so that M. Stein does not hesitate to give the preference to dyeing without mordants. Cotton, as might have been foreseen, will only take the color by means of a mordant; —the tin mordant appearing to give the best results. The color is an orange, very agreeable to the eye. This color, whether upon wool, silk, or cotton, resists perfectly the action of soap; alkalies, however, stain it yellow; and acids and salt of tin, turn it red. From the manner in which it behaves in these cases, it differs from annotto dye, to which it, however, bears great resemblance, as will be hereafter shewn,—the similarity extending to the action of the light upon the two bodies. This color, on being exposed to the light, very soon loses its color upon cotton, and a little more slowly upon wool: in this respect it appears to be more durable upon the unmordanted samples; but when employed for silk, it offers the most resistance; so that, compared with other yellow coloring matters, it may be considered to be one of the best.
On mordanting a woollen fabric with lime water, and passing it through a boiling bath of that substance, a fine yellow, inclining to red, was obtained, which resisted completely the action of soap, and also resisted the action of light better than the orange: alkalies, acids, and salt of tin, change it less than the orange, but in an analogous manner. Various fine shades of yellow may be obtained by adding to the bath carbonate of potash or caustic potash, and passing the unmordanted pieces through the bath at the ordinary temperature. The combination of the color with the fibre takes place very speedily, and with great uniformity and tenacity. By the addition of one part of potash to 30 parts of the coloring liquor, a yellow is obtained which is of a peculiar tint, owing to the presence of a small quantity of red. By doubling the quantity of potash, a bright yellow, inclining slightly to green, is obtained.—A larger addition of potash is not desirable, as the color becomes dull and uncertain. If caustic potash be used instead of the carbonate, a pure and lively yellow will be at first obtained, and containing little less red than that produced by the carbonate; and, afterwards, a fine canary yellow, with a slight tinge of green. Ammonia acts in the same manner as carbonate of potash and caustic potash; but the color is richer in red.— The coloring matter furnishes also somewhat different tints, when the fabric, after being washed, is passed through an alkaline bath.
The action of the alkalies is the same for silk and cotton; it is, however, a little less striking, as the fibres of silk and cotton absorb the coloring matter in less quantity than wool. The manner in which the coloring matter of wongshy acts, in common with annotto dye, is explained by the chemical character of the former, which is presented as a weak acid. It is from this circumstance that it has a disposition to combine with alkalies, and even with alkaline earths, as is shewn by the precipitation by waters of baryta and lime. The combinations which it forms with the former possess a pure yellow color, and are decomposed by the more energetic acids: when the coloring matter is thus set free, it assumes a lively cinnabar red. The matter, thus eliminated, is not the same as that which was originally in the aqueous solution, as it has become completely insoluble in water, and is only dissolved in small quantity by pure alcohol, ether, and alcohol at 80° Cent., which it colors yellow. Its color in the damp state is a cinnabar red; in a dry and most pure state, a brownish-red; and, like extract of ratanhia, it is easily reduced to powder; but, when it contains sugar and fatty matter, it pre sents, if inspected in thick layers, a fine yellow color; and, while in thin layers, it appears yellow and translucid, and draws humidity from the air. When the pure matter is heated on a sheet of platina, a yellow vapour is first disengaged, and the color is, in some places, pure yellow; it subsequently changes to a black, melts, and becomes carbonized. The resulting ash is very combustible;—the yellow vapours condense in yellow oily drops when the experiment is conducted in a small glass tube. Concentrated sulphuric acid brings out a faint blue, and the acid is colored with the same tint, which passes speedily to violet and brownred; whilst the coloring matter is slowly dissolved. With water, a flaky precipitate is formed, of a dirty yellowish-grey.
* To obtain it pure, with the etherieal solution, M. Stein evaporated the ether and treated the residuum with an aqueous solution of marine salt, in order to separate the fatty matter, which was then filtered off; the liquor was then evaporated at 50 per cent., and the residuum removed by means of alcohol. On afterwards evaporating the alcohol, a brown residuum was obtained, which had no bitter taste, and was insoluble in water.
** M. Stein remarked, in one instance, in the solution, concentrated by evaporation by the aid of a magnifying glass, detached white crystals, and others in theThe change of annotto to a blue tint by the action of sulphuric acid has no analogy with the phenomena presented by the coloring matter of wongshy, as the liquor is never, as is the case with annotto, colored a pure blue, but only presents traces of it—being violet for an instant only. It is easily soluble in ammonia and caustic soda, to which it imparts a gold color. In order to obtain it pure, an extract is made, by means of pure alcohol, from the bruised pods of wongshy; the alcohol is then separated by distillation, and the residue is treated with ether (to deprive it of the fatty matter), and afterwards dissolved in water; the solution is then treated with basic acetate of lead, with the addition of ammonia, and a precipitate is obtained. The plumbic precipitate, after being well washed and diluted with water, is afterwards decomposed by hydrosulphuric acid. On afterwards heating the liquor separated from the sulphuret of lead by the hydrochloric acid, it will be colored green; and, on evaporating it, a brown substance will be obtained, insoluble in water, and which is probably a product of the decomposition of the bitter substance above mentioned; a great part of which will, together with the fatty matter, have been carried away by the ether.* If, after drying the sulphuret of lead, it be treated with pure alcohol, it will assume a yellow color, and give up, by evaporation** the cinnabar red coloring matter, which is afterwards changed to brown-red. The product is, however, so small, that the quantity obtained by M. Stein did not allow of an elementary analysis being made. Nevertheless, by the help of M. Levol's method of testing, M. Stein ascertained that it did not contain any azote, neither could any traces of sulphur be detected on boiling with caustic ley.
The insolubility of the coloring matter in water, after being separated from the basic oxides, in contradistinction to its easy solubility before entering into combination with those oxides, led M. Stein to make some experiments, with the view of discovering the explanation of this phenomenon. One proof, that neither sugar nor pectine, in any way, influence the solubility of the coloring matter, is, that a solution containing sugar will, after having been boiled in caustic soda, allow the coloring matter to be precipitated, by means of vinegar; and this prepared and pure matter is neither soluble in a pure solution of pectine nor in a solution of sugar. One fact which seemed remarkable was, that the precipitation by acids took place immediately after having boiled an aqueous solution of the matter in caustic soda; while, at the ordinary temperature, a much longer time was required. M. Stein concluded from this, that the coloring matter originally existed in a state of combination, which was completely destroyed by boiling with the caustic soda. He supposes it to be an ammoniacal combination; for, as before remarked, a disengagement of ammoniacal gas was observed on boiling with caustic soda. This disengagement is, it is true, scarcely observable at the ordinary temperature; and, on the addition of chloride of platinum, even when the liquor is evaporated, no ammoniacal platinum is formed. This fact seems, therefore, to justify the opinion, that the coloring matter of wongshy is a starchy compound; and this opinion is supported by the fact, that the matter, after the solution has been boiled with caustic ammonia, cannot be precipitated by acids, but that it is capable of pecipitation from the aqueous solution, which still contains sugar, by boiling it with hydrochloric acid: in this case it should be remarked, that it is not of a cinnabar red color, but a brown-yellow, by reason of the pro ducts of decomposition of the sugar which were present.
M. Stein observes, in conclusion, that wongshy contains 5 per cent. of ash, which is obtained at a low temperature, and in an entire state, by mixing the pounded fruit with powdered platina. It was observed, in some experiments (in which plntina was not employed), that, at a certain temperature, there was, each time, sudden and violent combustion, which led to the belief that the fruit, perhaps, contained saltpetre. M. Stein, therefore, treated the fruit (deprived as much as possible of coloring matter by means of alcohol) with water, and endeavoured to detect the presence of nitric acid in the extract by means of sulphate of iron; he also treated another portion with sulphuric acid, but no traces were perceptible.
The ash of wongshy rapidly absorbs humidity from the air, and effervesces briskly with acids. On saturating it with nitric acid, M. Stein determined the proportion of phosphoric acid which it contains, according to M. H. Rose's process; i.e., by the help of mercury, and other ingredients usually employed.
100 parts of ash contain—
Phosphoric acid 10.27 = 5.75 0
Silica 400
Sulphuric acid 0.93
Chlorine 0.55
Lime 11.96 = 3.36 O
Magnesia 3.47
Oxide of iron 5.51
Soda 11.35
Potash 29.19
77.23
The solution of this ash, neutralized by nitric acid, is precipitated of a fine yellow color, by nitrate of silver; and the proportion of oxygen contained in the lime, bears the same proportion to that in the phosphoric acid as that contained in the basic phosphate of lime, according to the formula CaO x PO5. The question, whether these two matters are really thus combined, is left undecided,—M. H. Rose having perfectly demonstrated, in a recent work, how little one is justified in pronouncing upon the state of combination of the inorganic elements of plants from the analysis of their ash. The greater part of the basic oxide above mentioned must be combined with an organic acid, as it is found in the ash combined with carbonic acid. The quantity amounts to 21-67 per cent., supposing the alkalies to be in the state of carbonates, and the loss of 1.10 per cent. observed, to be really owing to the carbonic acid combined with the magnesia; which acid, on incineration in the presence of the alkaline carbonates, is but imperfectly driven oflf from the magnesia.
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