Chapter 6

Oscar Reymann and Adolf Ronsch, of Manila, exhibited the ilang-ilang oil in Paris in 1878; the former also showed the Cananga flowers. The oil of the flowers of the before-mentioned _Michelia champaca_, which stood next to it, competes with the cananga oil, or ilang-ilang oil, in respect to fragrance.[1] How far the latter has found acceptance is difficult to determine; a lowering of the price which it has undergone indicates probably a somewhat larger demand. At present it may be obtained in Germany for about 600 marks (£30) the kilogramme.[2] Since the Cananga tree can be so very easily cultivated in all warm countries, and probably everywhere bears flowers endowed with the same pleasant perfume, it must be possible for the oil to be produced far more cheaply, notwithstanding that the yield is always small.[3] It may be questioned whether the tree might not, for instance, succeed in Algeria, where already so many exotic perfumery plants are found.

[Footnote 1: _Archiv der Pharmacie_, ccxiv. (1879), 18.]

[Footnote 2: According to information kindly supplied by Herr Reymann, in Paris, Nice, and Grasse, annually about 200 kilogrammes are used; in London about 50 kilogrammes, and equally as much in Germany (Leipsic, Berlin, Frankfort).]

[Footnote 3: 25 grammes of oil from 5 kilogrammes of flowers, according to Reymann.]

According to Guibourt,[1] the "macassar oil," much prized in Europe for at least some decades as a hair oil, is a cocoa nut oil digested with the flowers of _Cananga odorata_ and _Michelia champaca_, and colored yellow by means of turmeric. In India unguents of this kind have always been in use.

[Footnote 1: _Histoire Naturelle des Drogues Simples_, iii. (1850), 675.]

The name "Cananga" is met with in Germany as occurring in former times. An "Oleum destillatum Canangæ" is mentioned by the Leipsic apothecary, Joh. Heinr. Linck[1] among "some new exotics" in the "Sammlung von Naturund Medicin- wie, auch hierzu gehorigen Kunst- und Literatur Geschichten, so sich Anno 1719 in Schlesien und andern Ländern begeben" (Leipsic und Budissin, 1719). As, however, the fruit of the same tree sent together with this cananga oil is described by Linck as uncommonly bitter, he cannot probably here refer to the present _Cananga odorata_, the fruit-pulp of which is expressly described by Humph and by Blume as sweetish. Further an "Oleum Canangæ, Camel-straw oil," occurs in 1765 in the tax of Bremen and Verden.[2] It may remain undetermined whether this oil actually came from "camel-straw," the beautiful grass _Andropogon laniger_.

[Footnote 1: Compare Flückiger, "Pharmakognosic," 2d edit, 1881, p. 152.]

[Footnote 2: Flückiger, "Documente zur Geschichte der Pharmacie," Halle (1876), p 93.]

From a chemical point of view cananga oil has become interesting because of the information given by Gal,[1] that it contains benzoic acid, no doubt in the form of a compound ether. So far as I, at the moment, remember the literature of the essential oils, this occurrence of benzoic acid in plants stands alone,[2] although in itself it is not surprising, and probably the same compound will yet be frequently detected in the vegetable kingdom. As it was convenient to test the above statement by an examination I induced Herr Adolf Convert, a pharmaceutical student from Frankfort-On-Main, to undertake an investigation of ilang-ilang oil in that direction. The oil did not change litmus paper moistened with alcohol. A small portion distilled at 170° C.; but the thermometer rose gradually to 290°, and at a still higher temperature decomposition commenced. That the portions passing over below 290° had a strong acid reaction already indicated the presence of ethers. Herr Convert boiled 10 grammes of the oil with 20 grammes of alcohol and 1 gramme of potash during one day in a retort provided with a return condenser. Finally the alcohol was separated by distillation, the residue supersaturated with dilute sulphuric acid, and together with much water submitted to distillation until the distillate had scarcely an acid reaction. The liquid that had passed over was neutralized with barium carbonate, and the filtrate concentrated, when it yielded crystals, which were recognized as nearly pure acetate. The acid residue, which contained the potassium sulphate, was shaken with ether; after the evaporation of the ether there remained a crystalline mass having an acid reaction which was colored violet with ferric chloride. This reaction, which probably may be ascribed to the account of a phenol, was absent after the recrystallization of the crystalline mass from boiling water. The aqueous solution of the purified crystalline scales then gave with ferric chloride only a small flesh-colored precipitate. The crystals melted at 120° C. In order to demonstrate the presence of benzoic acid Herr Convert boiled the crystals with water and silver oxide and dried the scales that separated from the cooling filtrate over sulphuric acid. 0.0312 gramme gave upon combustion 0.0147 gramme of silver, or 47.1 per cent. The benzoate of silver contains 46.6 per cent, of metal; the crystals prepared from the acid of ilang-ilang oil were, therefore, benzoate of silver. For the separation of the alcoholic constituent, which is present in the form of an apparently not very considerable quantity of benzoic ether, far more ilang-ilang oil would be required than was at command.

[Footnote 1: _Comptes Rendus_, lxxvi. (1873), 1428, and abstracted in the _Pharmaceutical Journal_ [3], iv., p. 28; also in _Jahresbericht_, 1873, p. 431.]

[Footnote 2: Overlooking Peru balsam and Tolu balsam.]

Besides the benzoic ether and, probably, a phenol, mentioned above, there may be recognized in ilang-ilang oil an aldehyde or ketone, inasmuch as upon shaking it with bisulphite of sodium I observed the formation of a very small quantity of crystals. That Gal did not obtain the like result must at present remain unexplained. Like the benzoic acid the acetic acid is, no doubt, present in cananga oil in the form of ether.

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CHIAN TURPENTINE.

The following letter has been received by the editors of the _Repertoire de Pharmacie:_ For some months past, a good deal has been heard about a product of our island that had quite fallen into disuse, and which no one cared to gather, so much had the demand fallen off because a substitute for it had been found in Europe; I mean Chian turpentine.

As this product is destined to take a certain part in the treatment of cancer, according to some English physicians, permit me, sir, to give your readers a few interesting details, obtained on the spot, concerning the turpentine tree and its product.

The turpentine tree (_Pistacia terebinthus_ L.) has existed in our island for many centuries, judging from the enormous dimensions of some of these trees, compared, too, with their slow rate of growth. The trunks of some measure from 4 to 5 meters in circumference, and their heights vary from 15 to 20 meters. On my own land there is an enormous tree, by far the largest on the island, the circumference of its trunk being 6 meters. Many of these great trees have been used in the construction of mills, presses, etc., on account of the hardness of their wood. It is in the vicinity of the town and in three or four neighboring villages that these trees are found. To-day, at a careful estimate, there may be 1,500 trees capable of yielding 2,000 kilos of turpentine, mixed with at least 30 per cent of foreign matter. There are no appliances for refining the product here, except the sieves through which it is passed to remove the pebbles and bits of wood which are found in it.

It is gathered from incisions made in the tree in June. Axes are used for this purpose, and the incision must be through the whole thickness of the bark. Through these outlets the turpentine falls to the foot of the tree, and mixes with the earth there. On its first appearance the turpentine is of a sirupy consistence, and is quite transparent; gradually it becomes more opaque, and of a yellowish-white color. It is at this period also that it gives off its characteristic odor most abundantly.

It is, however, not the product "turpentine" that is most esteemed by the natives, but the fruit of the tree, a kind of drupe disposed in clusters. The fruit is improved by the incisions made in the tree for the escape of the turpentine, otherwise the resin, having no other outlet, would impregnate the former, hinder its complete development, and render it useless for the purposes for which it is cultivated. One circumstance worth noting is that, as soon as the fruit commences to ripen, the flow of turpentine completely ceases. This is toward August; the fruit is then green; it is gathered, dried in the sun, bruised, and a fine yellowish-green oil is drawn from it, which is soluble in ether. This oil is used for alimentary purposes, but rarely for illumination since the introduction of petroleum. It is mostly used in making sweet cakes, and often as a substitute for butter, in all cases where the latter is employed. I use it daily myself without perceiving any difference.

I may here be permitted to correct a slight mistake that has crept into several standard botanical works. It is therein stated that the inhabitants of this country extract from the fruit of the lentisc (_Pistacia lentiscus_ L., a well-known shrub growing on this island, from which Chian mastic is obtained), an alimentary and illuminating oil. This fruit has never been gathered for its oil within the memory of man. The lentisc has probably been thus mistaken for the turpentine tree.

For the last twenty years the gathering of turpentine has been almost abandoned, although the incisions in the trees have been regularly made, but the value was so small that proprietors did not care to collect it, and left it to run to waste. There were but a few pharmacists of Smyrna and the neighboring islands who took a small quantity for making medicinal plasters. An utterly insignificant quantity found its way into Europe. How is it then that, after so many years, it was found in Europe? The problem is easily explained--the greater part came from Venice. This is indubitable, and, lately, an English chemist, Mr. W. Martindale, in a communication to the Chemical Society of London, expressed doubts as to the authenticity of the turpentine used in the treatment of cancer. If turpentine can really somewhat relieve this disease, and if this treatment is generally accepted in Europe, I much fear you will only obtain substitutions of very inferior quality to the turpentine produced in our island.

This year the Chians have been surprised by an extensive demand for this product, from London in the first place, and secondly from Vienna, and the proprietors, although but poorly provided at the moment, sent away nearly 600 kilos Paris has not yet made any demand. Yours, etc.,

DR. STIEPOWICH.

Chio, Turkey.

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ON THE CHANGE OF VOLUME WHICH ACCOMPANIES THE GALVANIC DEPOSITION OF A METAL.

By M. E. BOUTY.

In previous notes I have established, first, that the galvanic depositions experience a change of volume, from which there results a pressure exercised on the mould which receives them; second, that the Peltier phenomenon is produced at the surface of contact of an electrode and of an electrolyte. Fresh observations have caused me to believe that the two phenomena are connected, and that the first is a consequence of the second. The Peltier effect can clearly be proved when the electrolysis is not interfered with by energetic secondary actions, and particularly with the sulphate and nitrate of copper, the sulphate and chloride of zinc, and the sulphate and chloride of cadmium. For any one of these salts it is possible to determine a value, I, of the intensity of the current which produces the metallic deposit such that, for all the higher intensities the electrode becomes heated, and such that it becomes cold for less intensities. I will designate this intensity, I, under the name of _neutral point of temperatures_.

The new fact which I have observed is, that in the electrolysis of the same salts it is always possible to lower the intensity of the current below a limit, I', such that the compression produced by the deposit changes its direction, that is to say, instead of contracting the metal dilates in solidifying. This change, although unquestionable, is sufficiently difficult to produce with sulphate of copper. It is necessary to employ as a negative electrode a thermometer sensitive to 1/200 of a degree, and to take most careful precautions to avoid accidental deformations of the deposit; but the phenomenon can be observed very easily with nitrate of copper, the sulphate of zinc, and the chloride of cadmium. There is, therefore, a _neutral point of compression_ in the same cases where there is a neutral point of temperatures. With the salts of iron, nickel, etc., for which the neutral point of temperatures cannot be arrived at, there is also no neutral point of compression; and the negative electrode always becomes heated, and the deposit obtained is always a compressing deposit.

I have determined, by the help of observations made with ten different current strengths, the constants of the formulæ which I have explained elsewhere, and which gives the apparent excess, y, of the thermometer electrode compressed by the metallic deposit in terms of the time, t, during which the metal was depositing:

A t (1) y = ------- B + t

The constant, A, is proportional to the variation of volume of the unit of volume of the metal. The values of A, without being exactly regular, are sufficiently well represented within practical limits by the formula:

(2) A = - a'i + b'i²,

of the same form as the expression E:

E = - ai + bi²,

of the heating of the thermometer electrode. Further, every cause which affects the coefficients, a or b, also affects in the same way a' and b': such causes being the greater or less dilution of the solution, the nature of the salt, etc. It is, therefore, impossible not to be struck by the direct relation of the thermic and mechanical phenomena of which the negative electrode is the origin. The following is the explanation which I offer: The thermometer indicates the mean temperature of the liquid just outside it; this temperature is not necessarily that of the metal which incloses it. The current, propagated almost exclusively by the molecules of the decomposed salt, does not act directly to cause a variation in the temperature of the dissolving molecules; these change heat with the molecules of the electrolyte, which should be in general hotter than those when a heating is noticed and colder when a cooling is observed. Suppose it is found, in the first case, that the metal, at the moment when it is deposited, is hotter than the liquid, and, consequently, than the thermometer; it becomes colder immediately after the deposit, and consequently contracts; the deposit is compressed. The reverse is the case when the metal is colder than the liquid; the deposit then dilates. If this hypothesis is correct, the excess, T, of the temperature of the metal over the liquid which surrounds the thermometer should be proportional to the contraction, A, represented by the formula (2), and the neutral point, I', of the contraction corresponds to the case where the temperature of the metal is precisely equal to that of the liquid.

It might be expected, perhaps, from the foregoing, that I' = I; this would take place if the excess of temperature of the metal, measured by the contraction, were rigorously proportional to the heating of the liquid, for then the two quantities would be null at the same time. Careful experiment proves that this is not the case. The sulphate of copper gives compressing deposits on a thermometer which is undoubtedly cooling; chloride of zinc of a density 200 can give expanding deposits on a thermometer which is heating. There is, therefore, no proportionality; but it must be remarked that the temperature of the metal which is deposited does not depend only on the quantities of heat disengaged in an interval of molecular thickness which is infinitely small compared with the thickness of the layer, of which the variations of temperature are registered by the thermometer. There is nothing surprising, therefore, that the two variations of temperature, according exactly with one another, do not follow identically the same laws.--_Comptes Rendus._

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ANALYSES OF RICE SOILS FROM BURMAH.

By R. ROMANIS, D.Sc., Chemical Examiner, British Burmah.

The analyses of rice soils was undertaken at the instance of the Revenue Settlement Survey, who wanted to know if the chemical composition of the soil corresponded in any way to the valuation as fixed from other evidence. It was found that the amount of phosphoric acid in the soil in any one district corresponded pretty well with the Settlement Officers' valuation, but on comparing two districts it was found that the district which was poorer in phosphoric acid gave crops equal to the richer one. On inquiry it was found that in the former the rice is grown in nurseries and then planted out by hand, whereas in the latter, where the holdings are much larger, the grain is sown broadcast. The practice of planting out the young crops enables the cultivator to get a harvest 20 per cent. better than he would otherwise do, and hence the poorer land equals the richer.

The deductions drawn from this investigation are, first, that, climate and situation being equal, the value of soil depends on the phosphoric acid in it; and, second, that the planting-out system is far superior to the broadcast system of cultivation for rice.

Results of two analyses of soils from Syriam, near Rangoon, are appended:

_Soluble in Hydrochloric Acid_.

I. II. Virgin Soil. Organic matter 4.590 8.5?8 Oxide of iron and alumina 8.939 7.179 Magnesia 0.469 0.677 Lime trace. 0.131 Potash 0.138 0.187 Soda 0.136 0.337 Phosphoric acid 0.100 0.108 Sulphuric acid 0.025 0.117 Silica ---- 0.005 -------- --------- 14.397 17.249

_Soluble in Sulphuric Acid_.

Alumina 17.460 15.684 Magnesia 0.459 0.446 Lime 0.286 trace. Potash 0.616 1.250 Soda 0.317 0.285 --------- --------- 19.138 17.665

_Residue_.

Silica, soluble 11.675 \ 69.546 " insoluble 49.477 / Alumina 3.062 4.178 Lime 0.700 0.134 Magnesia 0.212 trace. Potash 0.276 1.180 Soda 0.503 1.048 -------- --------- 100.000 100.000

These are alluvial soils from the Delta of the Irrawaddy.

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DRY AIR REFRIGERATING MACHINE.

A large number of scientific and other gentlemen interested in mechanical refrigeration lately visited the works of Messrs. J. & E. Hall, of Dartford, to inspect the working of one of their improved horizontal dry air refrigerators!

The machine, which is illustrated below, is designed to deliver about 10,000 cubic feet of cold air per hour, when running at the rate of 100 revolutions per minute, and is capable of reducing the temperature of the air from 90 deg. above, to about 50 deg. below zero, Fah., with an initial temperature of cooling water of 90 deg. to 95 deg. Fah. It can, however, be run at as high a speed as 140 revolutions per minute. The air is compressed in a water-jacketed, double-acting compression cylinder, to about 55 lb. per square inch --more or less according to the temperature of the cooling water--the inlet valve being worked from a cam on the crank shaft, to insure a full cylinder of air at each stroke, and the outlet valves being self acting, specially constructed to avoid noise in working and breakages, which have given rise to so much annoyance in other cold air machines. The compressed air, still at a high temperature, is then passed through a series of tubular coolers, where it parts with a great deal of its heat, and is reduced to within 4 deg. or 5 deg. of the initial temperature of the cooling water. Here also a considerable portion of the moisture, which, when fresh air is being used, must of necessity enter the compression cylinder, is condensed and deposited as water.

After being cooled, the compressed air is then admitted to the expansion cylinder, but as it still contains a large quantity of water in solution, which, if expansion was carried immediately to atmospheric pressure, would, from the extreme cold, be converted into snow and ice, with a positive certainty of causing great trouble in the valves and passages. It is got rid of by a process invented by Mr. Lightfoot, which is at the same time extremely simple and beautiful in action, and efficient. Instead of reducing the compressed air at once to atmospheric pressure, it is at first only partially expanded to such an extent that the temperature is lowered to about 35 deg. to 40 deg. Fah., with the result that very nearly the whole of the contained aqueous vapor is condensed into water. The partially expanded air which now contains the water as a thick mist is then admitted into a vessel containing a number of grids, through which it passes, parting all the while with its moisture, which gradually collects at the bottom and is blown off. The surface area of the grids is so arranged that by the time the air has passed through them it is quite free from moisture, with the exception of the very trifling amount which it can hold in solution at about 35 deg. Fah., and 30 lb. pressure. The expansion is then continued to atmospheric pressure and the cooled air containing only a trace of snow is then discharged ready for use into a meat chamber or elsewhere. In small machines the double expansion is carried out in one cylinder containing a piston with a trunk, the annulus forming the first expansion and the whole piston area the second, but in larger machines two cylinders of different sizes are used, just as in an ordinary compound engine. To compensate for the varying temperature of the cooling water the cut-off valve to the first or primary expansion is made adjustable; and this can either be regulated as occasion requires by hand, or else automatically. The temperature in the depositors being kept constant under all variations in cooling water, there is the same abstraction of moisture in the tropics as in colder climates, and the cold air finally discharged from the machine is also kept at a uniform temperature.