Scientific American Supplement, No. 275, April 9, 1881

Mr. Vivian Lewes read a paper on "Pentathionic Acid." In March last the author, at the suggestion of Dr. Debus, undertook an investigation of pentathionic acid, the existence of which has been denied. The analyses of the liquid obtained by Wackenroder and others, by passing sulphureted hydrogen and sulphur dioxide through water, are based on the assumption that only one acid is present in the solution, and consequently do not establish the existence of pentathionic acid; as, for example, a mixture of one molecule of H

S

O

and one molecule of H

S

O

would give the same analytical results as H

S

O

. Moreover, no salt of pentathionic acid has been prepared in a pure state. The author has succeeded in preparing barium pentathionate thus: A Wackenroder solution was about half neutralized with barium hydrate, filtered, and the clear solution evaporated in vacuo over sulphuric acid. After eighteen days crystals, which proved to be barium pentathionate + 3 molecules of water, formed. These crystals were separated, and the liquid further evaporated, when a second crop was obtained intermediate in composition between the tetra and pentathionate. These were separated, and the mother-liquor on standing deposited some oblong rectangular crystals. These on analysis proved to consist of baric pentathionate with three molecules of water. This salt dissolves readily in cold water; the solution is decomposed by strong potassic hydrate, baric sulphite, hyposulphites, and sulphur being formed. By a similar method of procedure the author obtained potassium pentathionate, anhydrous, and with one or two molecules of water. The author promises some further results with some other salts of the higher thionates.

The president said that the society had to thank the author for a very complete research on the subject of pentathionic acid. He, however, begged to differ from him as to his statements concerning the researches of Messrs. Takamatsu and Smith; in his opinion these authors had proved the existence of pentathionic acid. He hoped that the crystals (which were very fine) would be measured.

Dr. Debus said that no one had previously been able to make the salts of pentathionic acid, and expressed his sense of the great merit due to the author for his perseverance and success. The paper opened up some highly interesting theoretical speculations as to the existence of hexathionic acid. If potassium tetrathionate was dissolved in water it could be re-crystallized, but potassium pentathionate under similar circumstances splits into sulphur and tetrathionate; but a mixture of tetrathionate and pentathionate can be re-crystallized. It seemed as if the sulphur when eliminated from the pentathionate combined with the tetrathionate.

Dr. Dupré asked Dr. Debus how it was that a molecule of pentathionate could be re-crystallized, whereas two molecules of pentathionate, which should, when half decomposed, furnish a molecule of tetra and a molecule of pentathionate, could not.

Dr. Armstrong then read a "Preliminary Note on some Hydrocarbons from Rosin Spirit." After giving an account of our knowledge of rosin spirit, the author described the result of the examination of the mixture of hydrocarbons remaining after heating it with sulphuric acid and diluting with half its volume of water and steam distilling. Thus treated rosin spirit furnishes about one-fourth of its volume of a colorless mobile liquid, which after long-continued fractional distillation is resolved into a variety of fractions boiling at temperatures from 95° to over 180°. Each of the fractions was treated with concentrated sulphuric acid, and the undissolved portions were then re-fractionated. The hydrocarbons dissolved by the acid were recovered by heating under pressure with hydrochloric acid. Besides a cymene and a toluene, which have already been shown to exist in rosin spirit, metaxylene was found to be present. The hydrocarbons insoluble in sulphuric acid are, apparently, all members of the C

H

series; they are not, however, true homologues of ethylene, but hexhydrides of hydrocarbons of the benzene series. Hexhydro-toluene and probably hex-hydrometaxylene are present besides the hydrocarbon, C

H

, but it is doubtful if an intermediate term is also present. It is by no means improbable, however, that these hydrocarbons are, at least in part, products of the action of the sulphuric acid. Cahours and Kraemer's and Godzki's observations on the higher fractions of crude wood spirit, in fact, furnish a precedent for this view. Referring to the results obtained by Anderson, Tilden, and Renard, the author suggests that rosin spirit perhaps contains hydrides intermediate in composition between those of the C

H

and C

H

series, also derived like the latter from hydrocarbons of the benzene series. Finally, Dr Armstrong mentioned that the volatile portion of the distillate from the non-volatile product of the oxidation of oil of turpentine in moist air furnishes ordinary cymene when treated in the manner above described. The fact that rosin spirit yields a different cymene is, he considers, an argument against the view which has more than once been put forward, that rosin is directly derived from terpene. Probably resin and turpentine, though genetically related, are products of distinct processes.

The next paper was "On the Determination of the Relative Weight of Single Molecules," by E. Vogel, of San Francisco. This paper, which was taken as read, consists of a lengthy theoretical disquisition, in which the author maintains the following propositions: That the combining weights of all elements are one third of their present values; the assumption that equal volumes of gases contain equal numbers of molecules does not hold good; that the present theory of valency is not supported by chemical facts, and that its elimination would be no small gain for chemistry in freeing it of an element full of mystery, uncertainty, and complication; that the distinction between atoms and molecules will no longer be necessary; that the facts of specific heat do not lend any support to the theory of valency. The paper concludes as follows: "The cause of chemical action is undoubtedly atmospheric pressure, which under ordinary conditions is equal to the weight of 76 cubic centimeters of mercury, one of which equals 6.145 mercury molecules, so that the whole pressure equals 467 mercury molecules. This force–which with regard to its chemical effect on molecules can be multiplied by means of heat–is amply sufficient to bring about the highest degree of molecular specific gravity by the reduction of the molecular volumes. To it all molecules are exposed and subjected unalterably, and if not accepted as the cause of chemical action, its influence has to be eliminated to allow the introduction and display of other forces."

The next communication was "On the Synthetical Production of Ammonia, by the Combination of Hydrogen and Nitrogen in Presence of Heated Spongy Platinum (Preliminary Notice)," by G. S. Johnson. Some experiments, in which pure nitrogen was passed over heated copper containing occluded hydrogen, suggested to the author the possibility of the formation of ammonia; only minute traces were formed. On passing, however, a mixture of pure nitrogen (from ammonium nitrite) and hydrogen over spongy platinum at a low red heat, abundant evidence was obtained of the synthesis of ammonia. The gases were passed, before entering the tube containing the platinum, through a potash bulb containing Nessler reagent, which remained colorless. On the contrary, the gas issuing from the platinum rapidly turned Nessler reagent brown, and in a few minutes turned faintly acid litmus solution blue; the odor of NH

was also perceptible. In one experiment 0.0144 gramme of ammonia was formed in two hours and a half. The author promises further experiment as to the effect of temperature, rate of the gaseous current, and substitution of palladium for platinum. The author synthesized some ammonia before the Society with complete success.

The President referred to the synthesis of ammonia from its elements recently effected by Donkin, and remarked that apparently the ammonia was formed in much larger quantities by the process proposed by the author of the present paper.

Mr. Warington suggested that some HCl gas should be simultaneously passed with the nitrogen and hydrogen, and that the temperature of the spongy platinum should be kept just below the temperature at which NH

dissociates, in order to improve the yield of NH

.

"On the Oxidation of Organic Matter in Water" by A. Downes. The author considers that the mere presence of oxygen in contact with the organic matter has but little oxidizing action unless lowly organisms, as bacteria, etc. be simultaneously present. Sunlight has apparently considerable effect in promoting the oxidation of organic matter. The author quotes the following experiment: A sample of river water was filtered through paper. It required per 10,000 parts 0.236 oxygen as permanganate. A second portion was placed in a flask plugged with cotton wool, and exposed to sunlight for a week; it then required 0.200. A third portion after a week, but excluded from light, required 0.231. A fourth was boiled for five minutes, plugged, and then exposed to sunlight for a week; required 0.198. In a second experiment with well water a similar result was obtained; more organic matter was oxidized when the organisms had been killed by the addition of sulphuric acid than when the original water was allowed to stand for an equal length of time. The author also discusses the statement made by Dr. Frankland that there is less ground for assuming that the organized and living matter of sewage is oxidized in a flow of twelve miles of a river than for assuming that dead organic matter is oxidized in a similar flow.–Chem. News.

ROSE OIL, OR OTTO OF ROSES

By CHARLES G. WARNFORD LOCK

This celebrated perfume is the volatile essential oil distilled from the flowers of some varieties of rose. The botany of roses appears to be in a transition and somewhat unsatisfactory state. Thus the otto-yielding rose is variously styled Rosa damascena, R. sempervirens, R. moschata, R. gallica, R. centifolia, R. provincialis. It is pretty generally agreed that the kind grown for its otto in Bulgaria in the damask rose (R. damascena), a variety induced by long cultivation, as it is not to be found wild. It forms a bush, usually three to four feet, but sometimes six feet high; its flowers are of moderate size, semi-double, and arranged several on a branch, though not in clusters or bunches. In color, they are mostly light-red; some few are white, and said to be less productive of otto.

The utilization of the delicious perfume of the rose was attempted, with more or less success, long prior to the comparatively modern process of distilling its essential oil. The early methods chiefly in vogue were the distillation of rose-water, and the infusion of roses in olive oil, the latter flourishing in Europe generally down to the last century, and surviving at the present day in the South of France. The butyraceous oil produced by the distillation of roses for making rose-water in this country is valueless as a perfume; and the real otto was scarcely known in British commerce before the present century.

The profitable cultivation of roses for the preparation of otto is limited chiefly by climatic conditions. The odoriferous constitutent of the otto is a liquid containing oxygen, the solid hydrocarbon or stearoptene, with which it is combined, being absolutely devoid of perfume. The proportion which this inodorous solid constituents bears to the liquid perfume increases with the unsuitability of the climate, varying from about 18 per cent. in Bulgarian oil, to 35 and even 68 per cent. in rose oils distilled in France and England. This increase in the proportion of stearoptene is also shown by the progressively heightened fusing-point of rose oils from different sources: thus, while Bulgarian oil fuses at about 61° to 64° Fahr., an Indian sample required 68° Fahr.; one from the South of France, 70° to 73° Fahr.; one from Paris, 84° Fahr.; and one obtained in making rose-water in London, 86° to 89½° Fahr. Even in the Bulgarian oil, a notable difference is observed between that produced on the hills and that from the lowlands.

It is, therefore, not surprising that the culture of roses, and extraction of their perfume, should have originated in the East. Persia produced rose-water at an early date, and the town of Nisibin, north-west of Mosul, was famous for it in the 14th century. Shiraz, in the 17th century, prepared both rose water and otto, for export to other parts of Persia, as well as all over India. The Perso-Indian trade in rose oil, which continued to possess considerable importance in the third quarter of the 18th century, is declining, and has nearly disappeared; but the shipments of rose-water still maintain a respectable figure. The value, in rupees, of the exports of rose-water from Bushire in 1879, were–4,000 to India, 1,500 to Java, 200 to Aden and the Red Sea, 1,000 to Muscat and dependencies, 200 to Arab coast of Persian Gulf and Bahrein, 200 to Persian coast and Mekran, and 1,000 to Zanzibar. Similar statistics relating to Lingah, in the same year, show–Otto: 400 to Arab coast of Persian Gulf, and Bahrein; and 250 to Persian coast and Mekran. And Bahrein–Persian Otto: 2,200 to Koweit, Busrah, and Bagdad. Rose-water: 200 to Arab coast of Persian Gulf, and 1,000 to Koweit, Busrah, and Bagdad.

India itself has a considerable area devoted to rose-gardens, as at Ghazipur, Lahore, Amritzur, and other places, the kind of rose being R. damascena, according to Brandis. Both rose-water and otto are produced. The flowers are distilled with double their weight of water in clay stills; the rose-water (goolabi pani) thus obtained is placed in shallow vessels, covered with moist muslin to keep out dust and flies, and exposed all night to the cool air, or fanned. In the morning, the film of oil, which has collected on the top, is skimmed off by a feather, and transferred to a small phial. This is repeated for several nights, till almost the whole of the oil has separated. The quantity of the product varies much, and three different authorities give the following figures: (a) 20,000 roses to make 1 rupee's weight (176 gr.) of otto; (b) 200,000 to make the same weight; (c) 1,000 roses afford less than 2 gr. of otto. The color ranges from green to bright-amber, and reddish. The oil (otto) is the most carefully bottled; the receptacles are hermetically sealed with wax, and exposed to the full glare of the sun for several days. Rose water deprived of otto is esteemed much inferior to that which has not been so treated. When bottled, it is also exposed to the sun for a fortnight at least.

The Mediterranean countries of Africa enter but feebly into this industry, and it is a little remarkable that the French have not cultivated it in Algeria. Egypt's demand for rose-water and rose-vinegar is supplied from Medinet Fayum, south-west of Cairo. Tunis has also some local reputation for similar products. Von Maltzan says that the rose there grown for otto is the dog-rose (R. canina), and that it is extremely fragrant, 20 lb. of the flower yielding about 1 dr. of otto. Genoa occasionally imports a little of this product, which is of excellent quality. In the south of France rose gardens occupy a large share of attention, about Grasse, Cannes, and Nice; they chiefly produce rose-water, much of which is exported to England. The essence (otto) obtained by the distillation of the Provence rose (R. provincialis) has a characteristic perfume, arising, it is believed, from the bees transporting the pollen of the orange flowers into the petals of the roses. The French otto is richer in stearoptene than the Turkish, nine grammes crystallizing in a liter (1¾ pint) of alcohol at the same temperature as 18 grammes of the Turkish. The best preparations are made at Cannes and Grasse. The flowers are not there treated for the otto, but are submitted to a process of maceration in fat or oil, ten kilos. of roses being required to impregnate one kilo. of fat. The price of the roses varies from 50c. to 1 fr. 25c. per kilo.

But the one commercially important source of otto of roses is a circumscribed patch of ancient Thrace or modern Bulgaria, stretching along the southern slopes of the central Balkans, and approximately included between the 25th and 26th degrees of east longitude, and the 42d and 43d of north latitude. The chief rose-growing districts are Philippopoli, Chirpan, Giopcu, Karadshah-Dagh, Kojun-Tepe, Eski-Sara, Jeni-Sara, Bazardshik, and the center and headquarters of the industry, Kazanlik (Kisanlik), situated in a beautiful undulating plain, in the valley of the Tunja. The productiveness of the last-mentioned district may be judged from the fact that, of the 123 Thracian localities carrying on the preparation of otto in 1877–they numbered 140 in 1859–42 belong to it. The only place affording otto on the northern side of the Balkans is Travina. The geological formation throughout is syenite, the decomposition of which has provided a soil so fertile as to need but little manuring. The vegetation, according to Baur, indicates a climate differing but slightly from that of the Black Forest, the average summer temperatures being stated at 82° Fahr. at noon, and 68° Fahr. in the evening. The rose-bushes nourish best and live longest on sandy, sun-exposed (south and south-east aspect) slopes. The flowers produced by those growing on inclined ground are dearer and more esteemed than any raised on level land, being 50 per cent. richer in oil, and that of a stronger quality. This proves the advantage of thorough drainage. On the other hand, plantations at high altitudes yield less oil, which is of a character that readily congeals, from an insufficiency of summer heat. The districts lying adjacent to and in the mountains are sometimes visited by hard frosts, which destroy or greatly reduce the crop. Floods also occasionally do considerable damage. The bushes are attacked at intervals and in patches by a blight similar to that which injures the vines of the country.

The bushes are planted in hedge-like rows in gardens and fields, at convenient distances apart, for the gathering of the crop. They are seldom manured. The planting takes place in spring and autumn; the flowers attain perfection in April and May, and the harvest lasts from May till the beginning of June. The expanded flowers are gathered before sunrise, often with the calyx attached; such as are not required for immediate distillation are spread out in cellars, but all are treated within the day on which they are plucked. Baur states that, if the buds develop slowly, by reason of cool damp weather, and are not much exposed to sun-heat, when about to be collected, a rich yield of otto, having a low solidifying point, is the result, whereas, should the sky be clear and the temperature high at or shortly before the time of gathering, the product is diminished and is more easily congealable. Hanbury, on the contrary, when distilling roses in London, noticed that when they had been collected on fine dry days the rose-water had most volatile oil floating upon it, and that, when gathered in cool rainy weather, little or no volatile oil separated.

The flowers are not salted, nor subjected to any other treatment, before being conveyed in baskets, on the heads of men and women and backs of animals, to the distilling apparatus. This consists of a tinned-copper still, erected on a semicircle of bricks, and heated by a wood fire; from the top passes a straight tin pipe, which obliquely traverses a tub kept constantly filled with cold water, by a spout, from some convenient rivulet, and constitutes the condenser. Several such stills are usually placed together, often beneath the shade of a large tree. The still is charged with 25 to 50 lb. of roses, not previously deprived of their calyces, and double the volume of spring water. The distillation is carried on for about l½ hours, the result being simply a very oily rose-water (ghyul suyu). The exhausted flowers are removed from the still, and the decoction is used for the next distillation, instead of fresh water. The first distillates from each apparatus are mixed and distilled by themselves, one-sixth being drawn off; the residue replaces spring water for subsequent operations. The distillate is received in long-necked bottles, holding about 1¼ gallon. It is kept in them for a day or two, at a temperature exceeding 59° Fahr., by which time most of the oil, fluid and bright, will have reached the surface. It is skimmed off by a small, long-handled, fine-orificed tin funnel, and is then ready for sale. The last-run rose-water is extremely fragrant, and is much prized locally for culinary and medicinal purposes. The quantity and quality of the otto are much influenced by the character of the water used in distilling. When hard spring water is employed, the otto is rich in stearoptene, but less transparent and fragrant. The average quantity of the product is estimated by Baur at 0.037 to 0.040 per cent.; another authority says that 3,200 kilos. of roses give 1 kilo. of oil.

Pure otto, carefully distilled, is at first colorless, but speedily becomes yellowish; its specific gravity is 0.87 at 72.5° Fahr.; its boiling-point is 444° Fahr.; it solidifies at 51.8° to 60.8° Fahr., or still higher; it is soluble in absolute alcohol, and in acetic acid. The most usual and reliable tests of the quality of an otto are (1) its odor, (2) its congealing point, (3) its crystallization. The odor can be judged only after long experience. A good oil should congeal well in five minutes at a temperature of 54.5° Fahr.; fraudulent additions lower the congealing point. The crystals of rose-stearoptene are light, feathery, shining plates, filling the whole liquid. Almost the only material used for artificially heightening the apparent proportion of stearoptene is said to be spermaceti, which is easily recognizable from its liability to settle down in a solid cake, and from its melting at 122° Fahr., whereas stearoptene fuses at 91.4° Fahr. Possibly paraffin wax would more easily escape detection.

The adulterations by means of other essential oils are much more difficult of discovery, and much more general; in fact, it is said that none of the Bulgarian otto is completely free from this kind of sophistication. The oils employed for the purpose are certain of the grass oils (Andropogon and Cymbopogon spp.) notably that afforded by Andropogon, Schoenanthus called idris-yaghi by the Turks, and commonly known to Europeans as "geranium oil," though quite distinct from true geranium oil. The addition is generally made by sprinkling it upon the rose-leaves before distilling. It is largely produced in the neighborhood of Delhi, and exported to Turkey by way of Arabia. It is sold by Arabs in Constantinople in large bladder-shaped tinned-copper vessels, holding about 120 lb. As it is usually itself adulterated with some fatty oil, it needs to undergo purification before use. This is effected in the following manner: The crude oil is repeatedly shaken up with water acidulated with lemon-juice, from which it is poured off after standing for a day. The washed oil is placed in shallow saucers, well exposed to sun and air, by which it gradually loses its objectionable odor. Spring and early summer are the best seasons for the operation, which occupies two to four weeks, according to the state of the weather and the quality of the oil. The general characters of this oil are so similar to those of otto of roses–even the odor bearing a distant resemblance–that their discrimination when mixed is a matter of practical impossibility. The ratio of the adulteration varies from a small figure up to 80 or 90 per cent. The only safeguard against deception is to pay a fair price, and to deal with firms of good repute, such as Messrs. Papasoglu, Manoglu & Son, Ihmsen & Co., and Holstein & Co. in Constantinople.

The otto is put up in squat-shaped flasks of tinned copper, called kunkumas, holding from 1 to 10 lb., and sewn up in white woolen cloths. Usually their contents are transferred at Constantinople into small gilded bottles of German manufacture for export. The Bulgarian otto harvest, during the five years 1867-71, was reckoned to average somewhat below 400,000 meticals, miskals, or midkals (of about 3 dwt. troy), or 4,226 lb. av.; that of 1873, which was good, was estimated at 500,000, value about £700,000. The harvest of 1880 realized more than £1,000,000, though the roses themselves were not so valuable as in 1876. About 300,000 meticals of otto, valued at £932,077, were exported in 1876 from Philippopolis, chiefly to France, Australia, America, and Germany.

–-Jour. Soc. of Arts.

A NEW METHOD OF PREPARING METATOLUIDINE

By OSKAR WIDMAN

The author adds in small portions five parts metanitro-benzaldehyd to nine parts of phosphorus pentachloride, avoiding a great rise of temperature. When the reaction is over, the whole is poured into excess of cold water, quickly washed a few times with cold water, and dissolved in alcohol. After the first crystallization the compound melts at 65°, and is perfectly pure.

A catalogue, containing brief notices of many important scientific papers heretofore published in the SUPPLEMENT, may be had gratis at this office.

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