ii. A mirror, which was found to consist of 85 parts of copper, 14

of tin, and 1 of iron per cent.; iii. A blue colour found in a tomb: [p210] it was composed of silica 70 parts; lime 9; oxide of copper 15; oxide of iron 1; soda mixed with potash 4. A blue identical with this, both in colour and composition, was found in the bottom of a furnace in which copper had been fused at Romilly.

M. D’Arcet has examined a bone from the fore part of an ox, which had been placed as an offering to the divinity in an Egyptian tomb, and found that it contained as much gelatine as recent bone, although rather less is obtained by muriatic acid, (20 per cent. instead of 27) because of a deterioration of the bone. When burnt, it gave an animal black as deep in colour as that from recent bone.

M. Le Baillif has examined some grains of corn, which were so well preserved, that when put into boiling water iodine produced the blue colour dependent upon starch. He also made some experiments on a gummy substance, and on two cords from a musical instrument; the latter were of animal substance.

M. Raspail examined some grain which was supposed to be wheat, but found it to be torrified barley; it was covered with a substance communicated probably by the oil and incense with which the grains were bathed when consecrated. Similar grains were obtained by roasting common barley.

The account of most of these researches is given in the Catalogue raisonné et historique des Antiquités découvertes en Egypte, by M. Passalacqua.—_Bull. Univ._ A. vii. 264.

24. _On the Bitter Substance produced by the action of Nitric Acid on Indigo, Silk, and Aloes_, _by_ M. Just Liebeg.—The process by which M. Liebeg obtains a pure and uniform substance from the action of nitric acid on indigo, is as follows:—A portion of the best indigo is to be broken into small fragments, and moderately heated with eight or ten times its weight of nitric acid of moderate strength. It will dissolve, evolving an abundance of nitrous vapours and swelling up in the vessel. After the scum has fallen, the liquid is to be boiled, and nitric acid added, whilst any disengagement of red vapours is occasioned by it. When the liquid has become cold, a large quantity of semi-transparent yellow crystals will be formed, and if the operation has been well conducted, no artificial tannin or resin will be obtained. The crystals are to be washed with cold water, and then boiled in water sufficient to dissolve them. If any oily drops of tannin form on the surface of the solution, they must be carefully removed by touching them with filtering paper. Then filtering the fluid, and allowing it to cool, yellow brilliant crystalline plates will be obtained, which will not lose their lustre by washing.

To obtain the substance perfectly pure, the crystals must be re-dissolved in boiling water, and neutralized by carbonate of potash. Upon cooling, a salt of potash will crystallize, which should be purified by repeated crystallizations.

On mixing the first mother liquor with water, a considerable brown precipitate will be obtained, which being dissolved in boiling [p211] water, and neutralized by carbonate of potash, will furnish a large quantity of the potash salt. All the potash salt obtained in these operations is to be re-dissolved in boiling water, and nitric, muriatic, or sulphuric acid added; as the solution cools, the peculiar substance will be observed to form very brilliant plates of a clear yellow colour, generally in equilateral triangular forms.

Sometimes crystals are not formed after the action of the nitric acid on the indigo, in which case the liquor must be evaporated, and water added, when the substance will precipitate, and must be purified as already described. Four parts of indigo yield one of the pure substance.

When the substance is heated, it fuses, and is volatilized without decomposition; when subjected to a sudden strong heat, it inflames without explosion, its vapours burning with a yellow flame, and a carbonaceous residue remaining. It is but little soluble in cold water, but much more in boiling water; the solution has a bright yellow colour, reddens litmus, has an extremely bitter taste, and acts like a strong acid on metallic oxides, dissolving them, and forming peculiar crystallizable salts.—Ether and alcohol dissolve the substance readily.

When fused in chlorine or with iodine, it is not decomposed, nor does solution of chlorine affect it. Cold sulphuric acid has no action on it; when hot, it dissolves it, but water separates the substance without alteration. Boiling muriatic acid does not affect it, and nitro-muriatic acid only with great difficulty.

These results show that no nitric acid is present in the substance, and other experiments prove that no oxide of nitrogen exists in it; it contains no oxalic or other organic acid, for when its salt is boiled with chloride of gold, the latter is not reduced.

When heated to redness with oxide of copper, it gave a mixture of nitrogen and carbonic acid, in the exact proportion of 1 volume of the former, to 5 of the latter. This was a constant result, and in no case was any sulphuric or muriatic acid left in the copper. 0.0625 grammes of the substance thus decomposed, gave 45 cubic centimeters of the mixed gases, estimated at 0° C. (32° F.) and the pressure of 28 inches of mercury, according to which the acid would be composed of carbon 32.392; nitrogen 15.2144; oxygen 52.3936 per cent. From the mean of several experiments, it appeared that the following might represent the composition correctly.—

12-1/2 atoms of carbon 93.75 or 31.5128 2-1/2 " azote 43.75 " 14.7060 16 " oxygen 160.00 " 53.7812 ------- -------- 297.5 100.

100 parts of the acid neutralize a quantity of base equivalent to 3.26 of oxygen, which is to the oxygen of the acid, as 1:16; the equivalent number of the acid derived from the analysis of the [p212] barytic salt was 306.3; by adding only 1/4 per cent. to the quantity of baryta obtained in the experiment, 297.5, or the number expressed by the above formula, would be obtained.

When a salt of potash or baryta was decomposed by oxide of copper and heat, the quantity of carbonic acid produced was a little short of five times the quantity of nitrogen; but, upon adding that retained by the alkali or earth, the proportion became exactly the same as in the former cases.

_Welter’s bitter principle_ was prepared by acting on silk with ten or twelve times its weight of nitric acid. The liquid, slightly coloured at first, acquired a deep yellow upon adding water. It was neutralized by carbonate of potash whilst hot, and left to cool, and the salt of potash thus obtained, decomposed by muriatic, nitric, or sulphuric acid. This acid, crystallized like that from indigo, formed the same salts, and was composed in the same manner. Silk furnishes much less of the substance than indigo. Dr. Liebeg has called this substance _carbazotic acid_. The most important salts formed by it have the following properties:—

_Carbazotate of Potash_—crystallizes in long yellow quadrilateral needles, semi-transparent and very brilliant; it dissolves in 260 parts of water at 59° F., and in much less, boiling water: a saturated boiling solution becomes a yellow mass of needles, from which scarcely any fluid will run. Strong acids decompose it; yet when an alcoholic solution of carbazotic acid is added to a solution of nitre, crystallized carbazotate of potash, after some time, precipitates.—Alcohol does not dissolve it. When a little is gradually heated in a glass tube, it first fuses, and then suddenly explodes, breaking the tube to atoms; traces of charcoal are observed on the fragments. This salt precipitates a solution of the protonitrate of mercury, but not salts, containing the peroxide, or those of copper, lead, cobalt, iron, lime, baryta, strontia, or magnesia. The slight solubility of this salt supplies an easy method of testing and separating potash in a fluid. Even the potash in tincture of litmus may be discovered by it; for, on adding a few drops of carbazotic acid, dissolved in alcohol, to infusion of litmus, crystals of the salt gradually separated. The saturated solution of the salt at 50° F., is not troubled by muriate of platina. The salt contains no water of crystallization. It was analyzed by converting a portion of it into chloride of potassium by muriatic acid: its composition is,—

Carbazotic acid 83.79 Potash 16.21 ------ 100.00

_Carbazotate of Soda_—crystallizes in fine silky yellow needles, having the general properties of the salt of potash, but soluble in from 20 to 24 parts of water, at 59° F.

_Carbazotate of Ammonia_ forms very long, flattened, brilliant, [p213] yellow crystals, very soluble in water. Heated carefully in a glass tube, it fuses, and is volatilized without decomposition; heated suddenly, it inflames without explosion, and leaves much carbonaceous residue.

_Carbazotate of Baryta_, obtained by heating carbonate of baryta, and carbazotic acid with water. It crystallizes in quadrangular prisms of a deep colour, and dissolves easily in water. When heated, it fuses, and is decomposed with very powerful explosion, producing a vivid yellow flame. The explosion is as powerful as that of fulminating silver; a solution of chloride of potassium to which carbazotate of baryta has been added, produces a precipitate of the potash salt, and not more than 1-1/2 per cent. of potash remains in solution. 100 parts of the crystallized salt contain,—

Carbazotic acid 69.16 oxygen of the acid 16 Baryta 21.60 " earth 1 Water 9.24 " water 8 ------- 100.00

_Carbazotate of Lime_, obtained like the salt of baryta, forms flattened quadrangular prisms, very soluble in water, and detonating like the salt of potash.

_Carbazotate of Magnesia_ forms very long indistinct needles, of a clear yellow colour; is very soluble, and detonates violently.

_Carbazotate of Copper_, prepared by decomposing sulphate of copper by carbazotate of baryta: it crystallizes with difficulty, the crystals being of a fine green colour; it is deliquescent; when heated, it is decomposed without explosion, and even without inflammation.

_Carbazotate of Silver_.—Carbazotic acid readily dissolves oxide of silver, when heated with it and water; and the solution, gradually evaporated, yields starry groups of fine acicular crystals of the colour and lustre of gold; the salt dissolves readily in water; when heated to a certain degree, it does not detonate, but fuses like gunpowder.

_Proto-Carbazotate of Mercury_, obtained in small yellow triangular crystals, by mixing boiling solutions of the carbazotate of potash or soda, and proto-nitrate of mercury. It requires more than 1200 parts of water for its solution: for its perfect purification, it should be heated with a solution of chloride of potassium, the insoluble portion separated whilst the liquid is lost, and the peculiar salt allowed to deposit as the temperature falls. When heated, it behaves like the salt of silver.

All these salts detonate much more powerfully when heated in close vessels, than when heated in the air; and it was a curious thing to observe, that those with bases yielding oxygen most readily, were those which exploded with least force. By heating some of the salts previously mixed with chloride of potassium, &c., to retard the action, it appeared that no carbonic oxide, but only carbonic [p214] acid and azote were evolved during their decomposition by heat.

_On the Bitter Principle from Aloes_.—Upon distilling 8 parts of nitric acid from 1 part of the extract of aloes, and adding water to the remaining fluid, a resinous reddish yellow substance precipitated, which, by washing, became pulverulent—it was discovered by M. Braconnot. Upon evaporating the liquid separated from the precipitate, it gave large yellow rhomboidal crystals, not transparent, and but slightly soluble. These crystals, at first mistaken for a particular substance, were soon found to be a combination of oxalic acid with the bitter of aloes. The bitter substances of aloes dissolved in 800 parts of water, at 59° F., but in a smaller quantity of boiling water. This solution has a superb purple colour. Silk boiled in it acquired a very fine purple colour, on which neither soap nor acids effected any change, except nitric acid; this changed the colour to yellow, but it was restored simply by washing in water. All shades may be given to this colour by proper mordants. Wool is dyed black in a peculiarly beautiful manner, by the same process, and light has no influence on the colour. Leather acquires a purple colour; cotton, a rose colour; but the latter will not resist soap. Dr. Liebeg thinks that this is the only substance from which a permanent rose dye for silk may be expected.—_Ann. de Chimie_, xxxv. 72.

25. _On the Existence of Crystals of Oxalate of Lime in Plants_.—M. Raspail has read a memoir to the Academy of Sciences, to prove the analogy which exists in arrangement between the crystals of silica, which are found in sponges, and those of oxalate of lime occurring in the tissue of phanerogamous plants.

The latter crystals were observed, for the first time, by Rafn and Jurine, who regarded them as organs of which they knew not the use. They were then observed by M. de Candolle, who called them _raphides_, and gave a figure of them, which, however, is inaccurate. These crystals are really very regular tetraedrons. In many plants, as _orchis_, _pandanus_, _ornithogalum_, _jacinthus_, _phytolaca_ _decandria_, _mesembryanthemum deltoides_, &c. they are very small, not being more than 1/200 of a millimetre (.0002 of an inch) in width, and 1/10 (.004 of an inch) in length. But, in the tubercles of the Florence iris, they are as much as 1/50 (.0008 of an inch) in width, and 1/3 (.01312 of an inch) in length, so as to be easily capable of examination.—_Bull. Univ._ B. xi. 376.

26. _Fallacy of Infusion of Litmus as a Test_, _by_ M. Magnus.—When pure water is heated for a sufficient time with infusion of litmus, reddened by an acid, it restores the blue colour. It is supposed that the heat gradually causes the free sulphuric acid, which had occasioned the reddening, to combine with the excess of alkali contained in the infusion, and thus to cause the restoration of the blue colour. Hence this preparation cannot be used to test the [p215] presence of ammonia in a solution, as water alone produces the effect anticipated from the alkali. The earthy salts contained in ordinary water also produce this effect.—_Jour. de Pharmacie_.

27. _Tests for the Natural Colouring Matter of Wine_.—M. A. Chevalier states,—i. That potash may be employed as a re-agent, to ascertain the natural colour of wines, which it changes from red to a bottle green, or brownish green—ii. That the change of colour produced by this substance upon wine is different for wine of different ages—iii. That no precipitation of the colouring matter takes place, the latter remaining dissolved by the potash—iv. That the acetate of lead should not be employed as a test of the colour of wines, because it is capable of producing various colours with wines of a natural colour only—v. That the same is the case with lime-water, with muriate of tin mixed with ammonia, and with subacetate of lead—vi. That ammonia may be employed for this purpose, the changes of colour which it produces not perceptibly varying—vii. That the same is the case with a solution of alum to which a certain quantity of potash has been added, and which may, therefore, be used for the purpose.—_Annales de l’Industrie_.

28. _Test of the Presence of Opium_.—Dr. Hare says he can detect opium in solution, when the quantity is not more than that given, by adding ten drops of laudanum to half a gallon of water. The following is the process:—a few drops of solution of acetate of lead is to be added to the solution containing the drug; after some time an observable quantity of meconiate of lead will fall down: from six to twelve hours may sometimes be required, and the precipitation is best effected in a conical glass vessel, for then, by gentle stirring now and then to liberate that which adheres to the side, the insoluble salt may be collected together at the bottom. About thirty drops of sulphuric acid are then to be poured on to the meconiate by means of a glass tube, after which as much of a solution of red sulphate of iron is to be added in the same manner. The sulphuric acid will liberate the meconic acid, and thus enable it to produce with the iron the appropriate colour, which demonstrates the presence of that acid, and consequently of opium.—_Silliman’s Journal_, xii. 290.

29. _Denarcotized Laudanum_.—Thinking it important to ascertain whether, by the removal of narcotine from opium, the unpleasant effects which, according to the opinions at present entertained upon that subject, are produced by that drug would be removed, Dr. Hare prepared some opium with ether, guided by Robiquet’s statement that narcotine was soluble in that fluid: the opium was shaved by rubbing it on the face of a jack-plane, and subjected four times successively to as much ether of the specific gravity 0.735 as would cover it, the operation being performed in a small Papin’s digester, at a temperature near the boiling point of ether, and each [p216] portion of the fluid being allowed twenty-four hours for its action. A crystalline deposition was soon observed in the ether which had been removed from the opium, and, allowing the stopper of the vessel to remain out, nearly the whole of the liquid evaporated in a few days, and left much coloured crystalline matter. This, Dr. Hare has no doubt, was narcotine in an impure state. The opium was afterwards subjected to as much alcohol as would have been required to convert it into laudanum, had it been in the ordinary state; and this being administered medicinally, was found to occasion none of those uneasy and unpleasant sensations which often follow the use of ordinary opium.—_Silliman’s Journal_, xii. 291.

30. _Extraction of Morphia from Dry Poppy Heads_, by M. Tilloy.—Make an aqueous extract of the heads, add alcohol to the extract, separate the alcoholic solution, and distil it; by this means the gummy matter is separated. An extract like syrup will be obtained by the distillation, which, being heated to make it thinner, and of the consistency of treacle, is to be again treated with alcohol; a separation of more gum, with much nitrate of potash, will be effected. The solution being withdrawn, is to be distilled, and the extract which will remain is to be acted upon by a sufficient quantity of water, and filtered, to separate the resinous matter present. The morphia may then be separated from this liquid, either by ammonia, carbonate of soda, or magnesia. Ammonia does not precipitate all the morphia; carbonate of soda precipitates a large quantity, but, it separates resinous matter also, which is found mingled with the morphia. Magnesia is preferable; but as the liquid contains much free acetic acid, it is expensive to employ the necessary quantity of pure magnesia: the liquid may, therefore, be partly saturated, whilst hot, by carbonate of magnesia, or even by carbonate of lime. A judgment, when no more must be added, must be formed from the effervescence; then pure magnesia is to be added, which will cause the liberation of ammonia; the whole is to be left for twenty-four hours to cool: being then filtered, the precipitate is to be washed, and, when dry, acted upon by alcohol. Operating in this manner, morphia may be obtained from all kinds of poppies.—_Bull. Univ._ E. viii. 10.

31. _Preparation of Morphia_.—Some curious experiments have been described to the Académie de Médecine, by M. Robinet, relative to the preparation of morphia. Having operated on the residue of opium by muriatic acid, and precipitated the morphia from the muriatic solution by lime, he wished to ascertain whether the mother liquor contained any morphia that had escaped precipitation. He, therefore, passed a current of carbonic acid gas through the solution, to precipitate the lime in excess: this precipitate being washed, dried, and acted upon by alcohol, was found mixed with a very large proportion of morphia, which could [p217] be thus separated. The washings of the precipitate being examined, were found free from morphia.

M. Henry observed, at the same time, that, from experiments made at La Pharmacie Centrale, it appeared that much more morphia was obtained in those processes in which lime had been used to precipitate the morphia, than in those in which magnesia had been used.—_Bull. Univ._ C. xi. 225.

32. _Easy Method of obtaining Meconic Acid_, by Dr. Hare.—If to an aqueous infusion of opium we add subacetate of lead, a copious precipitation of meconiate of lead ensues: this being collected by a filter, and exposed to sulphuretted hydrogen, meconic acid is liberated: the solution is of a reddish amber colour, and furnishes, by evaporation, crystals of the same hue. A very small quantity produces a very striking effect in reddening solution of peroxide of iron. Instead of sulphuretted hydrogen, sulphuric acid may be used to liberate the meconic acid: the presence of the former in excess does not seem to interfere with the power of reddening ferruginous solutions, but any excess of sulphuric acid may be removed by whitening, which is not acted upon sensibly by meconic acid; Yet, the acid procured in this way did not crystallize so handsomely, or with so much facility, as that obtained by sulphuretted hydrogen.

33. _On a New Vegetable Acid_.—This acid is crystallizable, but the forms have not as yet been determined: it is less soluble in cold water than tartaric acid; its aqueous solution precipitates lime water in white floculi, just like tartaric acid, but the precipitate, if dissolved in muriatic acid, re-appears on adding ammonia, whilst that produced by tartaric acid does not produce this effect. The new acid has a greater affinity for lime than muriatic or nitric acids, for it precipitates the muriate and nitrate of this earth in the manner of oxalic acid, but it differs from the latter in not precipitating a solution of sulphate of lime. With potash it forms an acid salt, slightly soluble in cold water: it precipitates acetate of lead, and the precipitate holds much water in combination: the tartrate of lead, on the contrary, is anhydrous. Notwithstanding these circumstances, the equivalent number of this acid is within a few thousandths of that of tartaric acid: when distilled, it is decomposed, and produces an acid yellow liquid like tartaric acid, leaving a light charcoal burning without residuum. M. Gay Lussac is engaged in developing the chemical history of this substance.—_Bull. Univ._ A. vii. 327.

34. _Altheine, a new Vegetable Principle_.—M. Bacon gives the following directions for the preparation of this substance, which he has discovered in the _Althea officinalis_. An extract of the roots of the plant is to be made by means of cold water, and, when concentrated, [p218] acted upon by boiling alcohol: the latter will dissolve the acid malate of altheine, oil, &c.: the different alcoholic decoctions are to be put together and will throw down a crystalline deposite as they cool; the latter is to be separated and dissolved in water, and the solution, when filtered, is to be evaporated by a moderate heat, until like a syrup, and then set aside to crystallize. The crystals procured are to be washed with a small quantity of pure water, to separate the yellow matter from them, and then dried upon paper. These crystals appear, to the naked eye, like grains, needles, and feathers, but under the microscope present a hexaedral form. They are of a fine emerald green colour, transparent, brilliant, inodorous; unaltered in the air; they redden litmus paper, are soluble in water, and insoluble in alcohol. The aqueous solution of these crystals, acted upon by cold magnesia and filtered, then restores the colour of reddened litmus paper; renders syrup of violets green; and when evaporated furnishes the altheine free from malic acid. When thus pure, the substance crystallizes in regular hexaedral forms or in rhomboidal octoedrons; it affects litmus and violets as just described: it is transparent, of an emerald green colour, brilliant, inodorous, slightly sapid, unaltered by air, very soluble in water, not soluble in alcohol, soluble in acetic acid, with which it forms a crystalline salt.—_Ann. de Chimie_, xxxiv. 201.

35. _Rheine, a new Substance from Rhubarb_.—By acting upon one part of Chinese rhubarb with 8 parts of nitric acid, s. g. 1.32, at a moderate temperature, reducing the whole to the consistence of syrup, and then diffusing it through water, M. Vaudin obtained a precipitate which possessed peculiar characters, and to which he gave the name of _Rheine_. When dry, it is of an orange yellow colour, without any particular odour, and slightly bitter. It dissolves in water as well as in alcohol and ether: the solutions become yellow by acids, and rose red by alkalis. It burns nearly in the manner of amadou. Rhubarb acted upon by ether only gave a similar substance, a circumstance which proves that Rheine exists ready formed in rhubarb, and that it is not acted upon by nitric acid.—_Ann. de Chimie_, xxxiv. 192.

36. _On Dragon’s Blood, and a new Substance which it contains_, _by_ M. Melandri.—Pure dragon’s blood is, according to M. Melandri, a scarce substance; the drops in which it occurs are rarely transparent, generally opaque, and with a rough fracture: its colour is blood red. Besides being soluble in alcohol it is entirely soluble in oil and also in hot water, though a large quantity of the latter fluid is required for the purpose. The aqueous solution is bitter, astringent, and of a fine purple colour; by cooling, it becomes milky and red. Gelatine does not alter its appearance; a proof that the substance contains no tannin. Sulphate of iron forms a pale reddish precipitate, so that no evidence of gallic acid is afforded. [p219]

Supposing that this substance might contain a principle analogous to that latterly observed by M. Pelletier in logwood, &c. a portion of it was dissolved in strong alcohol, the solution evaporated until very concentrated, and then poured into cold water, an agglomerated spongy substance was precipitated, which, after being washed with cold water and filtered, was triturated with water containing 1/100th of sulphuric acid, and exhibited traces of chemical action at a temperature of 22° (61°.6 F.) It then deposited a substance upon the sides of the vessel, and the liquid became yellow and very acid. The sediment, being carefully washed with water, was of a fine red colour, varying according to the state of aggregation; it had no taste or smell; was flexible between the fingers, and was quite fluid at 55° (131° F.). This substance, which the author has called _Dracine_, has some analogy with the vegeto-alkalis, although its affinity for acids is but slight. The sulphate may be obtained, he says, by adding sulphuric acid diluted with alcohol to an alcoholic solution of _dracine_, precipitating the mixture by cold water, and then applying a little heat; the sulphate of dracine collects at the bottom, is to be washed with cold water until the latter no longer reddens litmus paper, and then dissolved in hot water. This solution becomes red by the smallest quantity of alkalis, and may be used as a very sensible test of their presence. Dracine is also a good test for acids, assuming a yellow colour with them. The small quantity of carbonate of lime in filtering paper may be detected by sulphate of dracine, the yellow solution instantly becoming red from its action, and thus showing its presence.—_Bull. Univ._ C. xi. p. 157.

37. _Purification of Madder, by the Separation of its Yellow Colouring Matter_.—The experiments of MM. Kuhlman, Colin, and Robiquet[36], have induced M. G. H. de Kurrer to publish the means which he has resorted to for the purification of madder, by the separation of the yellow colouring matter from it; and thus rendering it more fit to supply the various red, lilac, violet, and brown colours which are required upon wool, silk, cotton and linen. Three tubs or vessels are placed by the side of each other: in summer they may be in the open air under shelter, but in the winter should be placed in an airy cellar where the temperature may be retained at 18° or 20° R. (73° to 77° F.). The first is that in which the soaking and fermentation is to be effected: it should be 2 feet 8 inches deep, and 2 feet 6 inches in diameter, for from fifty to fifty-five pounds of madder. The second, or washing vessel, should be 5-1/2 feet deep, and 3 feet in diameter; it should have three wooden cocks fixed into it, the first 2 feet, the second 3 feet, and the third 4 feet from the bottom. The third tub is for deposition; its height should be 4-1/2 feet, and it should have a cock at 1-1/2 foot from the bottom. [p220]

On commencing the operation, 50 or 55 lb. of pulverised madder are to be put into the first vessel, water is to be added, and stirred into the mass until it stands 1-1/2 inch above the madder. The whole is then to be left until fermentation comes on and has formed a coat of madder at the surface; this usually takes place in 36 hours, and at latest in 48 hours, according to the temperature. The mass should now be transferred into the second vessel, which is then to be filled with water, and being left for two hours, the madder will fall to the bottom. The upper cock is then to be opened, after that the second, and then the third; and the water which runs from the two latter is to be put into the third vessel, that the rest of the madder may separate from it. The madder in the second vessel is then to be washed a second, third, or fourth time until the washing water is colourless. Thus purified, the madder may be used in the processes of dyeing, according to the known methods; but it is important in summer that it should be used immediately, that a new (the vinous) fermentation may be avoided. The madder deposited in the third vessel, when washed and deposited, may be used like the rest. The liquid first separated after the fermentation may be used in the preparation of hot indigo baths, &c. instead of madder.—_Bull. Univ._ P. vii. 352.

FOOTNOTE:

[36] See page 239 of the last volume.

38. _On Indigo and Indigogene, by M. Liebeg_.—1-1/2 part of pure indigo, 2 parts of proto-sulphate of iron, 2-1/2 parts of hydrate of lime, and from 50 to 60 parts of water, were digested together for 24 hours in a close vessel, which had previously been filled with hydrogen. The clear liquor over the sulphate of lime and oxide of iron, had a yellowish red colour, and was separated by a syphon filled with hydrogen, and mixed with diluted muriatic acid, containing some sulphite of ammonia dissolved; a dense white precipitate was formed, becoming blue in the air. This was gathered in a filter without contact of air, and washed with boiled water containing sulphite of ammonia in solution, and dried at 212°, in close vessels, through which a current of hydrogen was continually passed. The upper surface of the mass became of a blue colour, but the lower remained of a dull white.

This white substance was called Indigogene. It did not change colour in dry air, but under water became of a deep blue, which by drying, assumed a coppery appearance. The blue substance volatilized by heat without leaving any residue, forming purple vapours, which condensed, when cold, into crystals differing in nothing from sublimed indigo. _Indigogene_ dissolves in alkalis without neutralizing them: it is also soluble in alcohol, but insoluble in water or acids.

A given quantity of this indigogene was acted upon by ammonia, and the weight of the undissolved blue portion ascertained, it appeared that the weight of the pure portion dissolved was 0.404 grammes (6.224 grains.) The solution was put into an inverted [p221] jar, over mercury, and oxygen gas gradually passed in until absorption ceased, and then the liquid containing the precipitated indigo was evaporated to dryness at 212°. The weight of the substance was increased to 0.047, _i. e._ 11.5 per cent.

Not having obtained indigogene _perfectly_ pure, M. Liebeg did not attempt to analyze it for the ultimate composition. He remarks, that indigo is, perhaps, the only organic body from which one of its constituent parts may be taken without total decomposition; and which, by oxidation, passes to the state of an indifferent body, having much analogy with peroxides.—_Ann. de Chimie_, xxxv. 269.

39. _On the mutual Action of Ethers, and other Substances_.—From experiments made by M. Henry, he concludes that when metals easily oxidizable, or oxides which unite with acetic acid, are put into sulphuric ether, they produce larger or smaller quantities of acetates, probably, not by decomposing the sulphuric ether, but the acetic ether which is always mixed with it; and that it is in consequence of the saturation of the acetic acid set free from the ether by this decomposition, that sulphuric ether does not redden litmus paper when evaporated, whereas it acts differently when being slightly heated, the quantity of acetic ether contained in it is allowed to decompose by the action of the air.

Nitric and acetic ethers are described as being easily decomposed by the action of many bodies without the assistance of heat, if aided by time. Amongst the products of the action are the acids of the ethers, acetates, and alcohol which dissolves the salts formed.—_Jour. de Chimie Méd_.

40. _Faraday’s Chemical Manipulation_.—The kindness of a friend at Bristol has pointed out to me an error in the directions relative to alkalimetry, which I have given in the above work: this I am desirous of correcting, and, by permission of Mr. Brande, have the opportunity of doing so in the _Quarterly Journal of Science_.

The mistake, which arose from using the wrong specific gravity of two that were required in calculation, occurs in the paragraphs (599, 600,) but fortunately is prevented from occasioning any experimental error by the directions given in (602). The acid of specific gravity, 1.141, directed to be used, is too strong for the quantities marked upon the tube. The substitution of one of specific gravity 1.127, will correct the error, and may be obtained very nearly by mixing 19 parts, by weight, of strong oil of vitriol, with 81 parts of water.

The alterations required may be made in the volume with a pen, as for errors of the press, by reading “1.127” for “1.141” in lines 25 and 30 of page 276, and lines 2 and 13 of page 277; and “nineteen” for “one” in line 27, and “eighty-one” for “four” in line 28 of page 276.—M. F. [p222]

III. NATURAL HISTORY.

1. _On the Supposed Influence of the Moon_, by M. Arago.—There is an impression very general with gardeners, that the moon has a particular effect on plants, especially in certain months. The gardeners near Paris gave the name of the _lune rousse_ to the moon, which, beginning in April, becomes full either at the end of the month, or more generally in May. According to them the light of the moon, in the months of April and May, injures the shoots of plants, and that, when the sky is clear, the leaves and buds exposed to this light become red or brown, and are killed, though the thermometer in the atmosphere is several degrees above the freezing point: they confirm this observation, by remarking that, when the rays of the moon are stopped in consequence of the existence of clouds in the air, that then the plants are not injured, although the temperature and other circumstances are the same.

M. Arago explains this observation of practical men, by a reference to the facts and principles established by Dr. Wells. He has shown that, in a clear night, exposed bodies may frequently have their temperatures reduced below that of the surrounding atmosphere, solely by the effect of radiation, the difference being as much as 6, 7, 10, or more degrees, but that it does not take place when the heavens are obscured. M. Arago then observes, that the temperature is often not more than 4, 5, or 6 degrees above the freezing point during the nights of April and May, and that when the night is clear, consequently when the moon is bright, the temperature of the leaves and buds may often be brought by radiation below the freezing point, whilst the air remains above it, and consequently an effect be produced, which, though not dependent upon, accompanies the brilliant unobscured state of the moon—the absence of these injurious effects, when the moon is obscured, being also as perfectly accounted for by these principles, from the knowledge that the same clouds which obscure the moon will prevent the radiation of heat from the plants. Hence, as M. Arago observes, the observation of the gardener is correct as far as it goes, though the interpretation of the effect which he generally gives is incorrect.—_Annuaire du Bureau des Long._ 1827, p. 162.

2. _Luminous Appearances in the Atmosphere_.—An account is given at page 242 of our last volume, from Silliman’s Journal, of certain spots in the air near the horizon, which have been seen highly luminous in Ohio, United States, by Mr. Atwater, and which often induce the supposition that fires exist in their direction. Mr. Webster says—“I have observed similar phenomena in New England: I recollect one instance, when I resided at Amherst, in Hampshire County, Mass., a bright light in the north-east, near [p223] the horizon, appeared as the light of a building on fire appears at night, at the distance of several miles. I expected, in that instance, every hour to hear that some building in Shutesbury, or New Salem, had been burnt, and, so strong was my belief of it, that I repeatedly asked my neighbours whether they had heard of any such event. At last, I met a gentleman who had just come from one of those towns, who told me he had heard of no fire from that quarter, which convinced me the phenomenon was merely atmospheric.”—_Silliman’s Journal_, xii. 380.

3. _On the Determination of the Mean Temperature of the Air_.—This subject has been investigated by M. G. G. Hallstrœm, who gives the following algebraic formula, which correctly represents the mean temperature for all Europe.

_v_ = 1/2 (_x_ _f_ + _x__e_)−0.33 + 0.41 sin. [(_n_−1) 30° + 124° 8′]

_v_ = mean temperature.

_n_ = the ordinal number of the month for which the temperature is to be calculated (thus, for March, _n_ = 3).

1/2 (_x_ _f_ + _x_ _e_) = the mean temperature taken as the mean of observations taken at ten o’clock in the morning and evening.

In winter 1/2 (_x_ _f_ + _x_ _e_) = _v_ very nearly; whilst, in summer, this quantity is 3/4 of a degree greater than _v_ at Paris, Halle, and Abo.—_Annal. der Phys. und Chem._ 1825, p. 373.

4. _Indelible Writing_.—As the art of man can unmake whatever the art of man can make, we have no right to expect an _indelible ink_: however, a sort of approximation to it may be made as follows:—Let a saturated solution of indigo and madder in boiling water be made, in such proportions as give a purple tint; add to it from one sixth to one eighth of its weight of sulphuric acid, according to the thickness and strength of the paper to be used: this makes an ink which flows pretty freely from the pen, and when writing, which has been executed with it, is exposed to a considerable, but gradual, heat from the fire, it becomes completely black, the letters being burnt in and charred by the action of the sulphuric acid. _If the acid has not been used in sufficient quantity to destroy the texture of the paper, and reduce it to the state of tinder, the colour may be discharged by the oxymuriatic and oxalic acids, and their compounds, though not without great difficulty_. When the full proportion of acid has been employed, a little crumpling and rubbing of the paper reduces the carbonaceous matter of the letters to powder; but by putting a black ground behind them, they may be preserved, and thus a species of _indelible writing_ is procured, (for the letters are, in a manner, stamped out of the paper,) which might be useful for some purposes, perhaps for the signature of bank-notes.

5. _Peculiar Crystals of Quartz_.—Mr. W. Phillips has met with some remarkable crystals of quartz, which occurred imbedded in the [p224] limestone of the Black-rock, near Cork. They are from the fourth to the half of an inch in length, and about half their length in width: they are smooth, externally, for the most part, and sometimes considerably bright; they are of the colour termed smoky, or brown quartz, externally, and may easily be separated from the limestone, leaving a cavity of their exact form. On trying to cleave them, they yielded parallel to one or other of the planes of the pyramid, like common quartz, but at such fractures appeared to consist of alternate and concentric prisms of smoky transparent quartz, and of gray opaque, and somewhat granular limestone. On applying muriatic acid to the surface, effervescence occurred along the gray parts, proving the presence of limestone, but soon ceased: after an action continued for some weeks, the gray parts became cellular, and so soft, as to admit of being scraped by a knife. Mr. Phillips says, it seems reasonable to conclude that such part of the gray substance as does not yield to the action of the acid is siliceous or quartzose; and that the prime difference between it and the smoky quartz surrounding it consists in the different circumstances of crystalline aggregation under which they are deposited. The crystals, with the somewhat analogous case of the Fontainebleau sandstone, may serve to assist in the illustration of some points relative to the laws of affinity, as operating in the formation of crystals.—_Phil. Mag._ N. S., ii. 123.

6. _Native Iron not Meteoric_.—The following notice is by Mr. C. A. Lee. Native iron, on Canaan mountain, a mile and a half from the South Meetinghouse (Conn. U. S.). This is particularly interesting, as it is the first instance in which native iron, not meteoric, has been found in America. It was discovered by Major Barrall, of Canaan, while employed in surveying, many years ago. It formed a thin stratum, or plate, in a mass of mica slate, which seemed to have been broken from an adjoining ledge. It presents the usual characters of native iron, and is easily malleable. For some distance around the place where it was found the needle will not traverse, and a great proportion of the tallest trees have been struck with lightning. Whether these phenomena are connected with the existence of a large mass of native iron, I leave for others to determine: the facts, however, may be relied on.

The specimen has been examined chemically, by Mr. Shepherd, at Yale College. It is invested with highly crystalline plumbago, and splits by the intervention of plates of plumbago into pyramidal and tetrahedral masses. It is not equal to meteoric iron in malleability, toughness, and flexibility, and has not the silvery white appearance of that iron. Its specific gravity is from 5.95 to 6.72. It has native steel intermingled in it, but contains no nickel, or any other alloy.

Major Barrall has only been to the place where this iron occurred _once_, and no other person has ever been to the place, or knows where it is.—_Silliman’s Journal_, xii. 154. [p225]

7. _Native Argentiferous Gold_.—M. Boussingault, who has had the opportunity of examining numerous specimens of argentiferous native gold from the Columbian mines, thinks that they are atomic; he has found 1 atom of silver united to 2, 3, 5, 6, and 8 atoms of gold, and considers it probable that the other combinations to complete the series may occur. He has assumed 24.86 as the number for gold, and 27.03 as the number for silver. The following are some of the experimental results:—

_Native Gold of Marmato_.—Pale yellow octoedral crystals: Gold 73.45 3 atoms 73.40 Silver 26.48 1 " 26.60 Loss 00.07

_Native Gold of Titiribi:_ Gold 74.00 3 atoms 73.40 Silver 26.00 1 " 26.60

_Native Gold of Malpaso_.—Yellow irregular flattened grains: Gold 88.24 8 atoms 88.04 Silver 11.76 1 " 11.96

_Native Gold of Rio-Sucio_.—Deep-coloured large irregular grains: Gold 87.94 8 atoms 88.04 Silver 12.06 1 " 11.96

_Native Gold of the Otra Mina_.—Pale yellow octoedral crystals: Gold 73.4 3 atoms 73.40 Silver 26.6 1 " 26.60

_Native Gold of Guamo_.—Brass-yellow indeterminate crystals: Gold 73.68 3 atoms 73.40 Silver 26.32 1 " 26.60

_Native Gold of Llano_.—Small flattened grains—reddish: Gold 88.58 8 atoms 88.04 Silver 11.42 1 " 11.96

_Native Gold of Baja_.—Porous: Gold 88.15 8 atoms 88.04 Silver 11.85 1 " 11.96

_Native Gold of Ojas-Anchas_.—Yellowish red plates: Gold 84.5 6 atoms 84.71 Silver 15.5 1 " 15.29

_Native Gold of Trinidad, near Santa Rosa de Osos_.—A solid piece of 50 grains: Gold 82.4 4 atoms 82.14 Silver 17.6 1 " 17.86

_Native Gold of Transylvania (Europe)_.—Pale yellow cubic crystals: Gold 64.52 2 atoms 64.77 Silver 35.48 1 " 35.23

_Native Gold of Santa Rosa de Osos_.—A mass weighing 710 grains: Gold 64.93 2 atoms 64.77 Silver 35.07 1 " 35.23

M. Boussingault has remarked a singlar deficiency in the [p226] specific gravity of the native alloys of gold and silver when compared with calculation, or with the results obtained from an alloy similar in composition prepared by fusion; thus the native gold of Marmato has a specific gravity of 12.666, whereas, by calculation, it ought to be 16.931. The gold of Malpaso, by experiment, is 14.706, by calculation, 18.223, and by fusion, 18.1. The gold of Santa Rosa, by experiment, is 14.149, and by calculation, 16.175. This difference, M. Boussingault says, is not due to porosity in the native gold, as he has observed it in the granular and fine varieties, but a peculiar character of the metal in this state. Such an enormous difference, however, is one that can be admitted only upon repeated experimental proofs, made in the most unexceptionable manner; and, considering that it is only in some of the metals that any permanent difference in specific gravity can be established, and even with them to but a small extent, would be a fact so important as to be worth extreme trouble in the verification.—_Annales de Chimie_, xxxiv. 408.

8. _Prothéeïte—a new Mineral_.—This mineral was discovered in 1826, at Rothenkoph, in the valley of Zillerthal, Tyrol. It occurs in rectangular prisms, generally without distinct summits, and rough at both ends. The angles are very seldom truncated, the faces are striated longitudinally. The crystals are of various sizes, some being very small, but they have occurred 5 inches in length, and two in width; the longitudinal fracture is lamellar, the cross-fracture conchoidal. The substance is usually fissured, nearly opaque in large specimens, translucent or diaphanous in small masses. Its colour is crysolite green or white, or between the two; its lustre between that of glass and the diamond; it is heavy; a good conductor of heat; hard enough to scratch glass; infusible before the blowpipe; highly electric by friction. The white crystals have a fibrous texture, which, as well as the colour, seems the result of decomposition. When cut and polished, the mineral assumes a great variety of aspects; the green parts then resemble the finest crysolites, but the fibrous white parts, when cut of a round form, present one or two reflections on a transparent ground which move as the stone is moved, just like those from the cat’s eye; these reflections are very brilliant, and are accompanied by numerous iris colours, which move like those on the opal. This phenomenon is often observed in the rough stone, which, when exposed to light, exhibit certain deep red tints of a cupreous colour, and metallic lustre on all the faces.—_Bull. Univ._ B. xi. 42.

9. _Volcanic Bisulphuret of Copper_.—M. N. Covelli, during his examinations of Mount Vesuvius, has observed some particular actions going on, especially in the fumeroles on the eastern side of the mountain, and within the crater. Speaking of the former, he says, “Here there are fumeroles in which pure chloride of lead [p227] sublimes into white and yellow crystallizations, which fusing in the hotter places form nacres, gum, and stalactites. In many parts the sulphuretted hydrogen, evolved within the fumeroles, reacts on the chloride, and forms sulphuret of lead, dispersed in small scales through the scoria. Other fumeroles produce very thin scales of the black oxide of copper; these are very brilliant, metalloidal, and flexible, and are produced by the action of the vapour of water at a red heat on the chloride of copper, which may be observed on disturbing the fumeroles. Here and there the reaction of aqueous vapour on the perchloride of iron produces metalloidal scales of the peroxide of iron; whilst further on, the same vapour, acting on mixtures of the two chlorides, produces oligiste iron in small crystals, aggregated on the scoria. The muriatic acid resulting from these actions, and the sulphuric acid which is formed by the decomposition of hydrosulphurets and sulphates, attack the iron, lime, copper, alumine, potash, &c., in the lavas and scoria, and hence result a number of other productions which line the passages of the fumeroles”.

M. Covelli descended into the crater, until within 300 feet of the edge of the large eastern opening, from which the great current of lava flowed in 1822. Here the fumeroles presented the most beautiful crystallizations of sulphate of lime and sulphur. On examining the scoria they were found incrusted and covered with a substance, having all the shades of colour belonging to blue, green, and black. Sometimes it resembled a spider’s web in appearance, sometimes soot deposited in the cavities of the scoria. Many specimens were collected, and also a portion of water condensed from the vapours which issued forth, and which evidently contained sulphuretted hydrogen and muriatic acid. The temperature of the vapour was as high as 85° C., in some places, and even up to 90°, at half a foot beneath the surface.

The water being examined was found to contain only a little sulphuretted hydrogen, and a little muriatic acid. The black substance was soon ascertained to be a pure sulphuret of copper. Being analyzed, 100 parts yielded 32 parts of sulphur, and 66 of copper, a loss of two parts being incurred, which accords very nearly with the composition of the bi-sulphuret of copper. The blue and bluish-green substances were found to be mixtures of this sulphuret with sulphate and hydro-sulphuret of copper.

M. Covelli concludes that this substance has been formed by the action of sulphuretted hydrogen on the sulphate and muriate of copper evolved by these fumeroles; and observes, that its composition accords with such an opinion, the deutoxide being that which forms the Vesuvian cupreous salts.—_Ann. de Chimie_, xxxv. 105.

10. _Fall of the Lake Souwando in Russia_.—This lake, situated in the parish of Sakkola, in the Russian government of Wibourg, and surrounded by the lands of the Barons Friedrichs, was near [p228] 40 versts in length, and had the form of a Γ, or Greek G. Before the year 1818, it was separated from the lake of Ladoga by an interval about a verst in width, called Taipale, on which was a sandy hill; its waters flowed into the river Wuoxa, which united the lakes of Saima and Ladoga. On the 14th May, 1818, the waters of the lake Souwando, increased by the thaw and the tempests, overcame the natural dyke at the foot of the lake, threw down the hill of sand, rapidly flowed into the lower lake, carrying away all the surrounding grounds, and for ever destroyed the barrier which had previously separated them. A chapel and a countryman’s house were carried away with the pastures and meadows; the waters of the lower lake were much disturbed, and the surface covered with ruins. The level of the lake Souwando fell 12-1/2 archines, and its length is now only 15 versts. Its waters no longer flow off by the Wuoxa, but pass into the lower lake by several falls through a deep canal. The land which has been uncovered by the water is already cultivated, and the beauty of the surrounding country said to be increased.—_Bull. Univ._, F. x. 133.

11. _Vegetable Torpor observed in the Roots of the Black Mulberry-tree_.—A very old mulberry-tree was broken into four quarters by the wind in 1790. Two of the quarters were destroyed, the other two remained growing for a few years, but the last of them was removed in 1802. An elder-tree grew in the place of the mulberry-tree, without doubt from berries which had fallen into the middle of the old trunk of the latter. This elder-tree died in 1826, and at the time of its languishing about a dozen of mulberry shoots started forth to the day. M. Dureau de la Malle ascertained that these did not spring from seeds, but from the roots of the old mulberry-tree, which had thus lain in the ground in an apparently inactive state, for 24 years, to send forth shoots at last.—_Ann. de Sciences Nat._ ix. 338.

12. _Method of increasing the Odour of Roses_.—For this purpose, according to the author of the method, a large onion is to be planted by the side of the rose tree in such a manner that it shall touch the foot of the latter. The roses which will be produced will have an odour much stronger and more agreeable than such as have not been thus treated, and the water distilled from these roses is equally superior to that prepared by means of ordinary rose leaves.—_Œkonom. Neuigk._;—_Bull. Univ._

13. _Pine Apples_.—A great improvement may be made in keeping pine apples by twisting off their crowns, which are generally suffered to remain and to live upon the fruit till they have sucked out all the goodness. It will be very easy for fruiterers to keep a few crowns by them in water, which can be pegged or stuck on with dough, for show, when the fruit is served up, or artificial ones [p229] may be made. A pine apple will keep for a long time when its crown is removed, and will also be greatly improved in flavour, for the more aqueous parts of the fruit gradually evaporate, and leave it much more saccharine and vinous in its flavour; which natural process is totally destroyed by the vegetation of the crown, just upon the same principle that an onion or carrot loses its flavour when it begins to sprout in the spring.

14. _Mode of Condensing and Preserving Vegetable Substances for Ships’ Provision, &c._—The quantity of liquid matter which enters into the constitution of vegetables is very great; when they are deprived of it their bulk is very trifling. That preparation of animal food called _pemmican_, in which six pounds of meat are condensed into the space of one, is mainly effected by abstracting all the fluid from it. Vegetables may be treated in the same way: let them undergo the process of boiling over a fierce wood fire, so as to preserve their colour when _completely_ cooked; grind them into a complete pulp by some such means as are used to crush apples for cider, &c.; then let them be subjected to the action of the press, (being first put into hair bags, or treated as grapes are in wine countries,) till all the fluid matter is separated from them; the remainder of their substance becomes wonderfully condensed, and as hard as the _marc_ from the wine press. Then let it be rammed hard into carefully glazed air-tight jars, (or tin cases, if preferred,) and subjected to the Appertian process for preserving animal and vegetable matters, (well known, by-the-by, to our grandmothers, who preserved gooseberries in this way from time immemorial.) If jars are used, they may be sufficiently secured by having two pieces of bladder tied successively over them; when the air within is absorbed by heating the inclosed substance, their surface becomes concave by the pressure of the atmosphere, and as long as it remains in this state the matter within is safe. If it should be thought requisite to preserve the flavour of the vegetables entire, an extract should be made from the expressed liquid, and added to the _marc_. But spinage, cabbage, and many others, have abundance of flavour in them in their dry state without this addition. The preparation of the vegetable matter for use is accomplished by adding a sufficient quantity of milk, water, gravy, lime juice, &c., to the _marc_, and warming it up. Let the government, and the dealers in ships’ provision, look to this; a sufficient quantity of this _vegetable pemmican_ would be the greatest luxury to a ship’s crew, and render the scurvy utterly obsolete. It is worthy of remark, that the most irritable stomach is not offended by vegetables treated in this way.

15. _Rewards for the Discovery of Quinia, and for Lithotrity_.—The Académie des Sciences has adjudged a prize of 10,000 francs to MM. Pelletier and Caventou, for their discovery and introduction [p230] into use of sulphate of quinia; and another prize of 10,000 francs to M. Civiale, for having been the first to practise lithotrity on the living body, and for having successfully operated by his method on a great number of persons afflicted with the stone in the bladder.

16. _Upon the Gaseous Exhalations of the Skin_.—M. Collard de Martigny, having experimented on this subject, has obtained results which tend to reconcile the differences existing between previous observers. The Count de Milly first announced, in the year 1777, that an aëriform fluid escapes in great quantity from the surface of the skin, and he considered the gas as carbonic acid. Cruikshank, Jurene, and Abernethy participated in this opinion. Ingenhouz, on the other hand, maintained that the air so secreted was azote. M. Frousset adopted the opinion of Ingenhouz, and endeavoured to confirm it by experiments. Lastly, Priestley and Fontana questioned the reality of a gaseous exhalation from the skin; and Fourcroy positively denied it.

From the experiments of M. Collard de Martigny, he deduces,

i. That a gaseous exhalation really takes place from the skin.

ii. This exhalation is not morbid: it is observable in health.