The elements of materia medica and therapeutics: Carbonate of lime (osia)

The elements of materia medica and therapeutics
by Jonathan Pereira, M.D. F.R.S. & L.S.
Fourth Edition, enlarged and improved, including notices of themost of the medicinal substances in use in the civilized world, and forming an Encyclopædia of Materia Medica.
Vol. I.
London: printed for Longman, Brown, Green, and Longmans, Paternoster Row.
1854.Preparation. — Several forms of carbonate of lime are employed in medicine — viz. marble, chalk, precipitated carbonate of lime, and carbonate of lime from animals: Most of these require to be submitted to some preparation before they are fitted for use.

1. Marble; Marmor; Carbonas Calcis (dura); Massive Crystalline Carbonate of Lime; White Marble, E.; Marmor album, D. — This is commonly employed for the preparation of carbonic acid, and for other purposes. White or statuary marble from Carrara should be selected, on account of its freedom from iron. It requires no Preparation.

2. Chalk; Creta; Calcis Carbonas (Friabilis in pulverem subtilissimum trita et elutriata), L.; Creta; Friable Carbonate of Lime; Chalk, E.; Creta, D. — This is found in great abundance in the southern parts of England. It is ground in a mill, and the finer particles are separated by washing them over in water, letting the water settle, and making up the sediment into flat cakes, which are dried in the air. In this state it is called whiting. Two of the British Colleges give directions for the preparation of chalk by elutriation. By this means it is separated from silicious and ferruginous particles. The product is called prepared chalk (Creta praeparata, E. D.) It is usually made up into little conical loaves.

The Dublin College orders of Chalk, lb. j.; Water, a sufficient quantity. Reduce the chalk to a fine powder, and having triturated this with as much water as will give it the consistence of cream, fill the mortar with water, and stir well, giving the whole a circular motion. Allow the mixture to stand for fifteen seconds, and then decant the liquid into a large vessel. Triturate what remains in the mortar, adding as much water as was previously used, and after allowing it to settle for fifteen seconds, again decant, and let this process be repeated several times. Let the fine sediment which subsides from the decanted liquid be transferred to a calico filter, and dried at a temperature not exceeding 212°.

The direction of the Edinburgh College is essentially the same.

The elements of materia medica and therapeutics: 2. Embrocatio iodinii - Iodine Paint.

The elements of materia medica and therapeutics
by Jonathan Pereira, M.D. F.R.S. & L.S.
Fourth Edition, enlarged and improved, including notices of themost of the medicinal substances in use in the civilized world, and forming an Encyclopædia of Materia Medica.
Vol. I.
London: printed for Longman, Brown, Green, and Longmans, Paternoster Row.
1854.

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¹ Practical Remarks on Gout, Rheumatic Fever, and Chronic Rheumatism of the Joints, pp. 187-88, Lond. 1843.This is a solution of iodine and iodide of potassium in alcohol: the iodide of potassium greatly facilitates the solution of the iodine. The following is Dr. Todd's¹ formula for it: — Iodinii, gr. lxiv.; Potassii Iodidi, gr. xxx.; Alcohol, ξj. M. — "The mode of application is by painting the part freely with a camel's-hair pencil. More or less smarting is produced, and frequently vesication or an herpetic eruption may come on. The painting may be repeated as often as circumstances may demand. It is extremely useful where any effusion has taken place into synovial membranes or sheaths."

The elements of materia medica and therapeutics: 3. Carbo Animalis. — Animal Charcoal.

The elements of materia medica and therapeutics
by Jonathan Pereira, M.D. F.R.S. & L.S.
Fourth Edition, enlarged and improved, including notices of themost of the medicinal substances in use in the civilized world, and forming an Encyclopædia of Materia Medica.
Vol. I.
London: printed for Longman, Brown, Green, and Longmans, Paternoster Row.
1854.(Carbo e sanguine bovino igne pneparatus, L. Carbo animalis, E. D.)

History. — This substance must have been known from the most ancient times. The kind usually met with in the shops is prepared from bones, and is termed bone black or animal black. It is sometimes sold as ivory black (ebur ustum nigrum).

Preparation. — Animal charcoal is extensively manufactured from bones for the use of sugar-refiners; and during the process an ammoniacal liquor (called bone spirit) is obtained as a secondary product. The operation is thus conducted: —

Bones are first boiled to remove the fatty matter which is used in soapmaking. The larger and finer pieces are then selected for the manufacture of buttons, handles of knives and tooth-brushes, &c; while the smaller and refuse portions are sold as manure. The remainder is submitted to distillation.

¹ See Ure's Dictionary of Arts and Manufactures, p. 10S1, figs. 951 aud 955, London, 1839.The stills or retorts are sometimes made of cast iron, and in shape and size resemble those used at gas-works. Formerly they were placed horizontally in the furnace,¹ and the volatile matters were conveyed away by a pipe opening into the ends of the retorts. To facilitate the speedy removal of the charcoal, they are sometimes placed obliquely in the furnace: the bones are introduced at the upper end, and the charcoal is removed from the lower end; — while the volatile matters are conveyed away by a side pipe. But these retorts are considered inferior to the vertical ones, on account of the facility and speed with which the latter can be charged and discharged. The vertical stills or retorts are made either of cast iron or of Welsh bricks; the latter, I am informed, are preferable. In a large manufactory of animal charcoal in this metropolis, the shape of the retort is that of a right rectangular prism; its height being twenty feet, its length about three feet, and its breadth two feet. It is closed at the top by a movable iron plate, secured by a screw bolt. It is closed below by a double trapdoor opening underground. Around the retort is a furnace of brickwork, whose shape is that of a truncated pyramid.


a. Furnace inclosing the retort.
b. Top of the retort.
c. Pipe to convey away the volatile products.
d. Water cistern, through which the volatile matter passes.
e. Pipe leading to
f. The iron receiver (an old steam boiler), com municating with a reservoir cistern under ground.
g. Second receiver.
h. Chimney inlo which the residual vapour passes.
i. Furnace door.
k. Crane.
l. Canister to receive the charcoal.
m. Steps leading to the lower end of the retort.

The bones are introduced at the upper end of the retort (b). The volatile products are conveyed away by the iron pipe (c). After passing through the cistern (d) they are conveyed to a series of receivers (f and y), where the brown ammoniacal liquor (bone spirit) and the empyreumatic oil (animal oil) are deposited. The uon-condensible portion is a fetid inflammable gas: this, after passing through water contained in the second receiver, is conveyed into a chimney, or is burned. The sobd residue in the retort is removed, while red-hot, through the lower and underground end of the retort, into wrought-iron canisters (I), which are instantly closed by iron covers, luted to make them air-tight, and then raised to the surface by a crane (k). When cold it is ground, and sold as animal, bone, or ivory black.

The volatile products of this operation are easily accounted for. When bones are heated, their cartilaginous or gelatinous portion uudergoes decom position, and its elements enter into new combinations. Some of the oxygen and hydrogen unite to form water. Carbon and oxygen, combining in dif ferent proportions, furnish carbonic oxide and acid. Carbon with hydro gen forms carbohydrogen; while nitrogen uniting with hydrogen produces ammonia, which, with some carbonic acid, forms carbonate of ammonia. The empyreumatic or animal oil consists of carbon, hydrogen, and oxygen, with probably some nitrogen.

Properties. — In its general properties animal charcoal agrees with char coal procured from wood. It is denser and less combustible than wood charcoal, but greatly exceeds the latter in its power of destroying colour and odour. In the crude state (carbo animalis crudus) it occurs in four forms in commerce: unground, and retaining the shape of the bones from which it was procured; coarsely ground (grain animal charcoal), as used by the sugar-refiners; more finely ground (coarse grit animal charcoal), as used by distillers; and finely ground or pulverised (fine animal charcoal). In the latter state it is frequently damped, and sold, at a lower price, as ivory black to the makers of blacking, &c.

Characteristics. — Animal charcoal yields, when burnt in oxygen gas or atmospheric air, carbonic acid, like other forms of carbon. From vegetable charcoal it may be distinguished by its texture and appearance, as well as by the nature and properties of its ashes. To obtain the ashes for examination a portion of the charcoal should be burned on a red-hot iron into white ashes. Wood ashes dissolve in sulphuric acid, and yield a bitterish solution: bone ashes are very sparingly affected by that acid, and form with it a compound having a very different taste.

¹ Dumas, Traité de Chimie, t. i. p. 450, Paris, 1828Composition. — Animal charcoal, prepared by calcining the bones of the ox, sheep, and horse, consists of the following ingredients:¹ —
Phosphate of lime
Carbonate of lime } ... 88.0
Charcoal ... 10.0
Carburet or siliciuret of iron ... 2.0
Sulphuret of calcium or iron ... traces
-----------------------------------------
Common Bone Black ... 100.0

The proportion of charcoal here stated is certainly small. Dr. Christison states that he has found, in the animal black of this country, usually about 20 per cent, of charcoal. When bone black is calcined in the open air, the carbon is burnt off, and a whitish residue is obtained, called bone ash. (See Calcis Subphosphas.)

For the ordinary purposes of the arts, as sugar-refining, crude animal char coal answers very well, because the earthy salts in no way affect the process. But in various pharmaceutical operations the presence of phosphate and carbonate of lime would preclude its use, on account of the free acid in the liquids to be decolorised. Hence the necessity of the purification of animal charcoal. (See Carbo animalis purificatus, p. 326.)

Animal charcoal, when deprived of its saline matters, usually contains traces of nitrogen. Dobereiner, indeed, supposed it to be a kind of subnitruret of carbon, composed of one equivalent or 14 parts of nitrogen, and six equivalents or 36 parts of carbon. Bussy, however, has shown, that though animal charcoal retains its nitrogen with considerable obstinacy, yet that the latter may be separated by heat.

Physiological Effects. — The remarks already made in reference to the physiological effects of wood charcoal apply equally well to animal charcoal.

¹ Pharmaceutical Journal, vol. ix. p. 78.

² Journal de Pharmacie, t. viii. p. 257, 1822.Uses. — The principal use of animal charcoal is as a decolorising agent in various pharmaceutical processes, as in the refining of sugar, the preparation of disulphate of quina, hydrochlorate of morphia, veratria, &c. The superior value of animal to vegetable charcoal for this purpose is usually referred to the minute separation of the carbonaceous particles effected by the presence of other matters, as of phosphate of lime, when bones are employed. Carbonate of potash is better for this purpose than phosphate of lime. The property possessed by minute particles of charcoal, of abstracting colouring matter from liquids, depends, probably, on some chemical affinities existing between carbon and colouring matter. It has been stated that charcoal which has been once used cannot have its decolorising property restored by a fresh ignition, unless it be mixed with some inorganic substance. This, however, is an error. The animal charcoal which has been used in sugar-refining is returned to the maker to be freshly ignited, and is then employed again, and this process of re-igniting is repeated many times, without any loss of decolorising power. [Animal charcoal can scarcely be regarded as a proper decoloriser in the preparation of the alkaloids, as it appears that many of these substances become removed from solution when digested with it. Morphia and strychnia are so affected, according to the experiments of Dr. Band, of Philadelphia.¹ — Ed.]

The following table, drawn up by Bussy,² shows the decolorising power of charcoal for indigo and molasses. The indigo test liquor contained 1/1000th of this substance; and, therefore, every gramme of the solution decolorised represents a millegramme (=0,0154 troy gr.) of indigo absorbed by the charcoal. The molasses solution consisted of one part molasses and twenty parts of water.

Kind of Charcoal employed. (Weigh talways 1 gramme = 15.434 troy grains.)	Solution of Indigo decolorized grammes	Solution of molasses decolorized grammes	Decolorizing power on Indigo.	Decolorizing power on Molasses.
1. Bone charcoal	22	9	1.00	1.00
2. Vegetable or animal oil charred with phosphate of lime	64	17	2.00	1.90
3. Bone charcoal washed with hydrochloric acid	60	15	1.87	1.60
4. No. 3 calcined with potash	1450	180	45.00	20.00
5. Calcined lamp-black	128	30	4.00	3.30
6. no. 5 calcined with potash	550	90	15.20	10.60
7. Charcoal of carbonate of soda decomposed by phosphorus	380	80	12.00	8.80
8. Charcoal of acetate of potash	180	40	5.60	4.40
9. Starch charred with carbonate of potash	340	80	10.60	8.80
10. Albumen charred with potash	1080	140	34.00	15.50
11. Gelatine charred with potash	1150	140	36.00	15.50
12. Blood charred with phosphate of lime	380	90	12.00	10.00
13. Blood charred with chalk	570	100	18.00	11.00
14. Blood charred with potash	1000	180	50.00	20.00

¹ Warington, Memoirs of the Chemical Society, vol. ii. p. 326, 1845; also Weppeu, Pharmaceutical Journal, vol. v. p. 326, 1846.The effect of animal charcoal in removing substances from their solutions is not limited to colouring matters: it also deprives liquids of their bitter principles, alkaloids, resins, tannin, and even some metallic salts.¹ It is obvious, therefore, that it cannot be employed to decolorise poisonous liquids, since it deprives the solution of more or less of its deleterious ingredient, as well as of its colouring matter. Moreover, it is clear that manufacturers who employ animal charcoal to decolorise their solutions must lose part of their product; and hence in the preparation of disulphate of quina, &c. a loss must be sustained by the employment of charcoal as a decoloriser.

² Pharmaceutical Journal, vol. v. p. 325, 1846.

³ On Poisons, p. 84, 1848.Dr. Garrod² has recently proposed purified animal charcoal as a general antidote in cases of poisoning; but I agree with Dr. Taylor³ in regarding the experiments adduced in favour of it as inconclusive. Like many other agents it is certainly capable of acting mechanically, and of thereby impeding the action of poisons (see ante, pp. 158, 159, and 165), but beyond this there is no evidence of its antidotal power.


CARBO ANIMALIS PURIFICATUS, E.D.; Purified Animal Charcoal. — The Edinhurgh College directs a mixture of lb. j. of Animal Charcoal and f?xij. each of Water and of Hydrochloric Acid to be boiled, after digestion for two days; then dilute with two pints of water: the undissolved charcoal, collected in a filter of linen and calico, is to be washed with water till what passes through scarcely precipitates with solution of carbonate of soda. The charcoal is to be heated first moderately, and then to redness in a closely covered crucible. — In this process the hydrochloric acid dissolves the phosphate of lime, and decomposes the carbonate of lime and sulphuret of calcium, evolving carbonic and hydrosulphuric acid gases, and forming chloride of calcium, which remains in solution. The carbonate of soda, used by the Edinburgh College, is for the purpose of detecting the presence of a calcareous salt in the washings.

The formula of the Dublin College is as follows: —

"Take of Ivory Black, lb. v.; Muriatic Acid of commerce, Oiij.; Water, Cong. ni. Oiij.; Distilled Water, as much as is necessary. To tho acid, diluted with Oiij. of water, gradually add tho ivory black, and digest, with repeated stirring, at a gentle heat, for twenty-four hours. Pour on now a gallon of water, and when, after the mixture has been well agitated, the insoluble matters have subsided, remove the clear solution by decantation, or the syphon. Let this be done a second and a third time. Place now the black sediment on a calico filter, and wash it with distilled water until the washings cease to give a precipitate with nitrate of silver. Finally, let the product be dried in a stove or oven, a gentle heat being at first applied, which must be finally raised to between 300° and 400°."

Purified animal charcoal causes no effervescence when mixed with hydro chloric acid, by which the absence of carbonate of lime is shown. Nor is any precipitate produced by the addition of ammonia, or its sesquicarbonate, to the acid which has been digested in the charcoal, by which the absence of any dissolved calcareous matter is shown: caustic ammonia would precipitate any phosphate of lime in solution, while its sesquicarbonate would yield a white precipitate with chloride of calcium. Purified animal charcoal, "when incinerated with its own volume of red oxide of mercury, is dissipated, leaving only a scanty ash [about 1/200th]." — Ph. Ed.

Purified animal charcoal is used as a decolorising agent in the preparation of the vegetable alkaloids, and as an antidote to poisons.

[Experiments by MM. Wassen and Graham, and also Drs. Garrod and Rand, seem to prove that the alkaloids, and some mineral poisons also, are prone to combine with purified animal charcoal, and become inert if sufficient of this latter substance be administered.

¹ Pharmaceutical Journal, vol. ii. p. 78.Dr. Garrod considers that animal charcoal has greater power of removing arsenic from its solutions than has the hydrated sesquioxide of iron; but tins is opposed to the results of the other above-mentioned experimenters.¹ — Ed.]

The elements of materia medica and therapeutics: 2. Carbo Ligni. — Wood Charcoal.

The elements of materia medica and therapeutics
by Jonathan Pereira, M.D. F.R.S. & L.S.
Fourth Edition, enlarged and improved, including notices of themost of the medicinal substances in use in the civilized world, and forming an Encyclopædia of Materia Medica.
Vol. I.
London: printed for Longman, Brown, Green, and Longmans, Paternoster Row.
1854.

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¹ Hist. Nat. lib. ivi. cap. 7.

² Kidd's Outlines of Mineralogy, vol. ii. p. 47.

³ Traitè de Chimie appliquée aux Arts, I. i. p. 561.

⁴ For some further details, consult Mr. Wilkinsou's work on the Engines of War, London, 1841Carbo e ligno igue prreparatus, L. Carbo ligni, E. D.

History. — "Wood charcoal must have been familiar to man from the most remote period of antiquity, and was probably known to the first inhabitants of the globe. For an account of the ancient method of procuring it, I must refer the reader to the works of Theophrastus (cap x.) and Pliny.¹

Natural History. — Wood charcoal is always an artificial product. Some samples of Bovey coal have very much the appearance of wood charcoal, but are readily distinguished by their containing hydrogen, in consequence of which they burn with a yellow flame. Moreover they are not good conductors of galvanic electricity.²

Preparation. — Ordinary wood charcoal is prepared, on the large scale, for the purposes of fuel, by burning billet-wood (oak, beech, hazel, and sometimes willow), piled in a conical heap, covered with turf and sand, to prevent the access of atmospheric air, a few holes being left near the bottom and one at the top to occasion a draught. The heap is then set fire to, and when the flame has pervaded the whole mass, the holes are closed. When cooled, the billets are found converted into charcoal. For an account of the mode of arranging the wood in heaps, consult Dumas.³

The charcoal used in the manufacture of gunpowder is prepared by the distillation of wood in cast iron cylinders, set horizontally (or nearly so) in brick work, over a furnace. The charge is introduced at the front, and the opening is then perfectly secured by an iron door and bar, well luted. The back part of each cylinder is perforated by two pipes, one above the other, and bent downwards into tubs containing water. The tar flows out by the lower pipe, and the pyroligneous acid by the upper one, and condenses in the receiver (the tub). The smoke and vapours escape into the air. When sufficiently burnt, the charcoal is raked out into iron boxes, which are immediately covered, to exclude the air.⁴ At the Waltham Abbey mills, charcoal is prepared from the Dogwood (Cornus sanguinea) the Alder (Alnus glutinosa), and the Willow (Salix). The Dogwood charcoal (which occasions a peculiar ringing sound when it falls on stones) is used for rifle powder: the other kinds for cannon and musket powder. Lieut-Col. Moody tells me that the Dutch White Willow (Salix Russelliana?) is the best kind of willow for charcoal, but that the Huntingdon Willow is also a good one. (See Acidum Aceticum.)

Box wood charcoal for galvanic purposes is prepared by putting prismatic pieces of box wood, about an inch long and half an inch thick, into a crucible, covering them with dry sand, and exposing them to a red heat for about an hour.

Properties. — Wood charcoal is black, odourless, and insipid. It has the texture of the wood from which it has been obtained. It is brittle, and may be easily pulverised, especially when hot. Though a very bad conductor of heat, it is an excellent conductor of electricity. It is insoluble, infusible, and incapable of volatilization. Its specific gravity varies according to the substance from which it has been obtained. A remarkable property possessed by it is that of abstracting certain substances (such as hydrosulphuric acid, organic colouring principles, various odorous matters, &c.) from liquids in which they are dissolved, or through which they are diffused. Another curious quality is that of condensing within its pores a certain quantity of any gas with which it may be placed in contact. Thus one volume of boxwood charcoal absorbs 1.75 volumes only of hydrogen gas, but 90 volumes of ammoniacal gas. Some of the properties now mentioned (as that of decolorising) are possessed, in a more eminent degree, by animal charcoal.

Characteristics. — By combustion in oxygen gas, wood charcoal yields carbonic acid gas, — a property by which it is shown to consist of carbon. Its texture and appearance, as well as the nature of the ashes which it leaves behind when burnt, serve to distinguish it from other forms of carbon. (See Animal Charcoal).

¹ Traité des Estais par la Voie seche, t. i. p. 286, Paris, 1834.Composition. — The following is the composition of charcoal obtained from different woods, according to the experiments of Berthier¹
— | Poplar. | Maple. | Ash. | Fir. | Alder. | Birch. | Oak. | Hazel.
Carbon | 85.6 | 85.2 | 83.2 | 90.3 | 88.1 | 88.0 | 87.7
Calcined Ashes | 1.0 | 1.0 | 1.8 | 2.2 | 1.8 | 1.9 | 2.0 | 2.0
Volatile Matters | 13.4 | 18.8 | 15.0 | 7.5 | 8.0 | 10.0 | 10.0 | 10.3
Charcoal | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0


Wood ashes consist of soluble alkaline salts and of insoluble matters. The alkaline salts have for their base potassium and sodium: they contain (or yield) carbonic, sulphuric and hydrochloric acids, a little silica, and sometimes a trace of phosphoric acid. The insoluble matters contain carbonic and phosphoric acids, silica, lime, magnesia, and the oxides of iron and manganese. The quantity of carbonic acid is never sufficient to saturate both the alkalies and the earths, in consequence of the heat having expelled carbonic acid from the earthy carbonates. (See Potassa Carbonas.)

² Dict. de Mat. Med. par MM. Mérat et De Lens, t. ii. art. Carbone.

³ Traité de Matière Médicale, par S. Hahnemann, traduite par A. J. L. Jourdan, Paris, 1834.Physiological Effects. — Wood charcoal I believe to be an inert substance, both with respect to animals aud vegetables. Burdin² gave a pound of it daily without producing any other effect than that of blackening the stools. A variety of properties and virtues have, however, been ascribed to it, — as I believe, without foundation: thus it has been termed anodyne, emmenagogue, tonic, purgative, &c. In the French edition of Hahnemann's Materia Medica,³ no less than thirty-five pages are occupied with the enumeration of the symptoms produced by one-millionth of a grain of this substance ! !

Uses. — In this country, charcoal is used as a therapeutic agent, principally as a disinfectant and antiseptic, to absorb the fetid odour evolved by gangrenous and phagedenic ulcers. For this purpose it may be used in the form of powder or of poultice. Its disinfecting aud antiseptic powers, however, are much inferior to those of chlorine, or of the chlorides [hypochlorites] of lime and soda.

¹ Considération sur l'Usage du Carbone en Médecine, Paris, 1808.As a tooth-powder it is a valuable agent, freeing the teeth from the foreign matters which cover them, and at the same time counteracting the unpleasant smell of the breath arising from decayed teeth or disordered stomach; but it is apt to lodge in the space between the gum and tooth, forming an un sightly livid circle (see ante, p. 159). Brachet¹ states that it checks caries of the teeth. Areca-nut charcoal is a favourite variety for tooth-powders. Its fancied superiority is ascribed to the extreme hardness of its particles.

² Edinburgh Medical and Surgical Journal, vol. x. p. 13.Internally, charcoal has been exhibited in various affections of the alimentary canal, such as dyspepsia, cardialgia, diarrhoea, cholera, and dysentery. The beneficial effects said to have been produced in these cases can only be referred to the action of charcoal on the secretions of the bowels; an explanation apparently supported by Dr. Chapman's statement, that in dysentery, when the stools are highly acrid and offensive, charcoal entirely divests them of the bad smell and acrimony. In consequence of the advantage said to have been obtained by Dr. Calcagno, of Sicily, by the use of charcoal in intermittent, it was tried by Dr. Calvert, physician to the British forces at Palermo, and with success.² In this country, however, I believe it is never resorted to in ague by medical practitioners. Dr. Daniel, of Savannah, has recommended it in obstinate constipation, and in the nausea and confinement of the bowels which frequently attend pregnancy. It has also been used in various other diseases, but experience has not confirmed its efficacy.

Administration. — The dose of charcoal, as ordered by different writers, varies from ten grains to a tablespoonful or more.

The elements of materia medica and therapeutics: 1. Plumbago vel Graphites. — Graphite or Black Lead.

The elements of materia medica and therapeutics
by Jonathan Pereira, M.D. F.R.S. & L.S.
Fourth Edition, enlarged and improved, including notices of themost of the medicinal substances in use in the civilized world, and forming an Encyclopædia of Materia Medica.
Vol. I.
London: printed for Longman, Brown, Green, and Longmans, Paternoster Row.
1854.

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¹ Essays, p. 246.

² Historia Naturalis, lib. xxxiv. cap. 47, 50, and 53, ed. Valp.

³ London Medical Gazette, vol. xviii. p. 267.

⁴ [In reference to the sources of plumbago, we find the following among some notes left by the late Dr. Pereira: — "Visited the Borrowdale lead mine; was told no plumbago bad been sent to market for three years; now engaged in running a level in order to find the vein; not been successful at present; the old workings are discontinued" (July 1849). In a note to Dr. Pereira, from a correspondent, we also find it stated that "Mexican black lead is much adulterated; sand, black clay, powdered black lead crucibles, and inferior qualities of lead, being used for the purpose. The finest plumbago is called pencil lead: the inferior, Naples lustre, Mexican jet, &c. Spanish plumbago is scarcely in the market."]History. — Plumbago (so called from its resemblance to plumbum or lead,) or graphite (from [], I write, on account of its use as a writing material), was probably known to the ancients; but it was first accurately distinguished from other bodies with which it had been previously confounded, especially with molybdena (bisulphide of molybdenum), by Scheele,¹ in 1779.

The terms plumbago, plumbum nigrum, and molybdena, met with in Pliny,² do not apply to graphite.

Natural History. — It is found in various parts of the world; chiefly in primitive rocks and the coal formations. It occurs at Borrowdale in Cumberland, in various parts of the continent of Europe (Bavaria, Bohemia, Spain, &c.), in Ceylon, and in the United States of America. A very pure graphite is found near Bustletown in Pennsylvania.

Graphite is found either crystallized or compact. Crystallized graphite (graphites crystallinus) may be foliated, scaly, or radiated,: its forms are thin six-sided tables belonging to the rhombohedric system. Compact graphite (graphites solidus) occurs either massive or disseminated.

Borrowdale plumbago is of fine quality. It is brought to London, and sold by auction at a public-house in Essex- street, Strand, on the first Monday in every month.³ The best quality usually sells for two guineas or more per pound, and is employed for making pencils.

Spanish Plumbago is imported from Malaga, It is probably obtained from the mountain of Mora, near Marbella, in Andalusia. It is sometimes of superior quality.

Ceylon or East India plumbago is another sort which is extensively imported. Its quality is inferior.

German plumbago is imported from Hamburgh. It is of inferior quality, and is said to be the produce of Bohemia. The so-called Mexican black lead is imported from Hamburgh.⁴

Properties. — As found in commerce, it is usually in kidney-shaped masses. Its colour is iron or steel-grey, with a metallic lustre. It has a greasy feel, and writes easily on paper. Its specific gravity is 2.08 to 2.45.

Characteristics. — It is known to be carbon by its yielding carbonic acid by combustion in oxygen gas. When burned, it usually leaves a residuum of silica and red oxide of iron. It is infusible before the blow-pipe. Its physical properties distinguish it from most other varieties of carbon. Some kinds of coal-gas charcoal (artificial graphite) closely resemble it. Of noncarbonaceous substances, molybdena (bisulphide of molybdenum) is the only substance that can be confounded with it in external appearance.

Purity. — Graphite usually contains traces of iron and silica. When of good quality it is free from all visible impurities (sand, stones, &c.) When heated before the blow-pipe, it should be infusible, and not evolve any odorous vapour or smoke: its freedom from metallic sulphurets (as of antimony and lead) is thereby shown. It is insoluble in alkalies and acids. Hydrochloric acid boiled with it should dissolve only some minute portions of iron; and the filtered acid liquid should yield no precipitate on the addition of carbonate of ammonia; and no change of colour when sulphuretted hydrogen is added to it.

The powder sold in the shops under the name of black lead, for polishing iron grates, &c. is an adulterated article, and is unlit for medicinal purposes. It is usually prepared by reducing the quality of the so-called Mexican plumbago (German plumbago) by grinding it with sand, old black lead crucibles, a substance called Bideford black (which am informed is a kind of black clay found near Bideford in Devonshire), and an inferior plumbago called common lead, seconds, or German gunpowder (from its being granulated like gunpowder). When reduced, it forms Naples lustre, Mexican jet, black lead, &c.

¹ Pharmaceutisches Central-Blatt für 1838, p. 524.

² Ann. Chim. el Physiq. 3ème ser. i. p. 1-54.

³ Silliman's Journal, vol. x. p. 105.

⁴ Proceedings of the Chemical Society, No. i. p. 12, 1841.

⁵ Ausfürlihe Arzneimittellehre, Bd. iii. p. 486, Berlin, 1828.Wackenroder¹ has signalised the existence of a commercial graphite, of which three-fourths were sulphuret of antimony.

For ordinary purposes, powdered graphite is purified by boiling it with nitro-muriatic acid, and then washing and drying it.

Dumas and Stas² purified it for analysis by heating it to redness with caustic potash, then washing it with water, boiling with nitric acid and nitro-muriatic acid to extract iron and bases, washing, drying, and then exposing it, at a white heat, to a stream of dry chlorine gas, by which chloride of iron and chloride of silicon were volatilised. When thus purified, it contained merely a trace of silica.

Composition. — It consists essentially of carbon, but is usually mixed with variable proportions of silica, iron, and other substances. The following are analyses of three varieties by Vanuxen:³
... | Borrowdale (pure) | Borrowdale (impure) | Bustletown (pure)
Carbon | 88,37 | 61,27 | 95,4
Water | 1,23 | 5,33 | 0,6
Silica | 5,10 | 10,10 | 2,6
Alumina | 1,00 | 3,20 | 0,0
Oxides of Iron, Mangmese, &c. | 3,60 | 20,00 | 1,4
Plumbago | 99,30 | 99,90 | 100,0

I suspect, however, that the finest varieties of the Borrowdale graphite contain a smaller quantity of foreign matter than is here stated. Graphite has been recently analysed by Dr. It. F. Marchand,⁴ who states that 1,4580 gramme of native graphite left a residue of pure white silica, without a trace of oxide of iron, weighing only 0.0075.

On the erroneous supposition that the carbon was chemically combined with iron, graphite was formerly called carburet or percarburet of iron. From some observations of Schrader, however, it would appear that the iron is in combination with titanic acid.

Physiological Effects. — Various properties have been assigned to it; but further evidence is wanting to establish its action on the body. Richter⁵ says it alters, in some way, the lymphatic secretion and the condition of the skin; and, after some days' use, causes increased secretion of urine, with difficulty in passing it.

Uses. — It has been employed both externally and internally in chronic diseases of the skin (as herpes). When used externally, it is employed in the form of ointment (Vnguentum plumbaginis), composed of from one to six drachms of plumbago to an ounce of lard. Internally the dose is ten or twelve grains to a drachm, or more.

The elements of materia medica and therapeutics: 5. Carbonium. - Carbon.

The elements of materia medica and therapeutics
by Jonathan Pereira, M.D. F.R.S. & L.S.
Fourth Edition, enlarged and improved, including notices of themost of the medicinal substances in use in the civilized world, and forming an Encyclopædia of Materia Medica.
Vol. I.
London: printed for Longman, Brown, Green, and Longmans, Paternoster Row.
1854.

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¹ [There ia a considerable difference of opinion among chemists respecting the equivalent number and volume of carbon vapour. In a work specially devoted to Materia Medica we have not thought it advisable to make any change. — Ed.]

² Edinb. Philosophical Journal, vol. iii. p. 98; and Philosophical Magazine, vol. i. p. 147, 1827.

³ Geological Transactions, 2d series, i. 419.

⁴ De la Beche, Researches in Theoretical Geology, p. 32, London, 1834.Symbol C. Equivalent Weight 6.¹ Equivalent Volume of Carbon Vapour (P) 1 or []

History. — The term carbon (from carbo, õnis, coal) was first employed by Morveau, Lavoisier, and Berthollet, to designate the pure matter of charcoal. To the second of these chemists we are indebted for demonstrating, that by combustion in oxygen gas the diamond and charcoal yield the same product — namely, carbonic acid gas.

Natural History. — Carbon is found in both kingdoms of nature:

a. In The Inorganised Kingdom. — When pure and crystallised, it constitutes the diamond, which Sir D. Brewster² suspects to oe of vegetable origin; but a specimen, described by Mr. Heuland,³ was found in a primary rock. Plumbago and anthracite consist principally of carbon. The bituminous substances (as coal, petroleum, naphtha, &c.) also contain it. These are admitted by geologists to be of vegetable origin. Carburetted hydrogen is evolved from coal strata, marshy places, stagnant waters, &c. Carbonic acid is found either in the free state, as in the atmosphere, in mineral waters evolved from the earth in old volcanic countries, &c, or combined with metallic oxides, in the form of the carbonate of lime, iron, &c. It is remarkable that carbon is rare among the older rocks.⁴

b. In the Organised Kingdom. — Carbon is an essential constituent of all organised beings, both vegetable and animal.


Properties. — Carbon is a solid, odourless, tasteless substance, neither fusible (?) nor volatile; combustible in oxygen gas, and yielding carbonic acid gas. The other properties of carbon are so varied, that chemists are obliged to admit distinct varieties of this substance: the principal are the diamond, plumbago, and charcoal (animal and vegetable). Of these, the two latter only require consideration in this work.

[Carbon, like oxygen, is now considered to assume the allotropic form, and to show varying chemical reactions in consequence. The diamond and plumbago must be regarded as merely allotropic forms of ordinary carbon. — Ed.]

The elements of materia medica and therapeutics: Hair Dyes

The elements of materia medica and therapeutics
by Jonathan Pereira, M.D. F.R.S. & L.S.
Fourth Edition, enlarged and improved, including notices of themost of the medicinal substances in use in the civilized world, and forming an Encyclopædia of Materia Medica.
Vol. I.
London: printed for Longman, Brown, Green, and Longmans, Paternoster Row.
1854.

---


¹ Paulus Æginela, translated by Mr. Adams, for the Sydenham Society, vol. i. pp. 342-4, 1844. — See also Galen, De Compos. Medicam. Secundum locos, lib. i.

² Medea is said to have been acquainted with the art of dyeing grey hairs black, and partly in consequence of this she had the reputation of being able to restore youth to old people.

³ Galen, supra cit.; Paulus, supra cit.; and Alexander Trallianus, i. 3.

⁴ The use of a composition of this kind, called Poudre d'ltalie, is said to have produced ophthalmia (Lond. Med. Gaz. Nov. 18, 1842).

⁵ See Gray's Supplement to the Pharmacopoeia, by Mr. Redwood, p. 740, Lond. 1847. Also, Journal de Chimie Médicale, tom. ii. p. 250, 2ndo ser.

⁶ Phoebus, Handbuch der Arzneiverordnungs-lehre, Th. ii. p. 148, 3tte Ausgabe, 1840.

⁷ Pharmaceutical Journal, vol. iii. p. 585.

⁸ Devergie, Médecine Legate, t. ii. p. 931, Turis, 1836; and Dr. Cummin, Lond. Med. Gaz. vol. xix. p. 215.Hair Dyes (tinctura capillorum) are chemical agents; but they are included in this class, because their employment usually devolves on the hair-dresser. Yet, occasionally, a knowledge of them is useful to the medical practitioner. "Galen, when about to treat of compositions for the hair, remarks that the application of these does not belong properly to the physician; but that he may sometimes be obliged to furnish them to royal ladies, whom, under certain circumstances, he cannot venture to disobey."¹

Hair dyes were in use by the ladies of antiquity;² and numerous recipes for their preparation are to be found in ancient medical authors.³

Various substances, — some mineral, others vegetable, — have been used as hair dyes. The base of most of the powders, pastes, and liquids sold in the shops, is either lead or silver. A mixture of finely-powdered litharge or carbonate of lead, and about an equal weight of slaked lime (to which starch is sometimes added) is frequently used.⁴ It is then put on to prevent evaporation, and in four or five hours is removed, and the dye washed out. The water causes the oxide of lead to unite with the lime, forming a plumbite of lime. The lime is useful by removing the grease of the hair, while the lead combines with the sulphur contained in the hair, and forms the black sulphuret of lead. Leaden [] on the same principle. Nitrate of silver is also extensively used as a hair dye. Hair, impregnated with a solution of this salt, blackens, partly by the reduction of the silver, partly by the formation of the black sulphuret of silver. Sometimes a solution of hydrosulphuret of ammonia, to which caustic potash has been added, is applied to the hair previous to the use of the nitrate, but a solution of gallic acid is preferable, and acts better than the hydrosulphuret. Other formulae for hair dyes have been published.⁵ The objections to the use of mineral hair dyes are, that, they commonly communicate a reddish or purplish tint, and render the hair dry, crisp, and brittle.

Various vegetable substances have been employed; as the green shells of walnuts (cortex nucum juglandis viridis). These are used in the form of decoction, or of the so-called walnut liquor. The "Tinctur zum Schwarzfärben der Haare" is an alcoholic tincture of these shells scented with oil of lavender.⁶ Pyro-gallic acid has recently been proposed as a hair dye.⁷

The detection of stained hair is sometimes an object of medico-legal research.⁸ Lead may be recognised in hair by boiling the latter in nitric acid, and applying the tests for lead to the nitric solution. To detect, silver, the hair must be treated with chlorine, to form chloride of silver, which is soluble in ammonia. From the ammoniacal solution the chloride may be precipitated by nitric acid, and its nature ascertained by the usual means.

XVII. Remarks on the Aurora Borealis. By Mr. Winn. p. 128. (1774)

The Philosophical Transactions of the Royal Society of London, For their commencement, in 1665, to the year 1800: Abridged, with notes and biographic illustrations by Charles Hutton, LL.D. F.R.S. George Shaw, M.D. F.R.S. F.L.S. Richard Pearson, M.D. F.S.A. VOL XIII From 1770 to 1776. London: Printed by and for C. And R. Baldwin, New Bridge-Street, Blackfriars. 1809I believe the observation is new, that the aurora borealis is constantly succeeded by hard southerly, or south-west winds, attended with hazy weather and small rain. I think I am warranted from experience to say constantly; for in 23 instances that have occurred since I first made the observation, it has invariably obtained.

The gale generally commences between 24 and 30 hours after the first appearance of the aurora. More time and observation will probably discover whether the strength of the succeeding gale is proportionate to the splendor and vivacity of the aurora, and the distance of time between them. I only suspect that the more brilliant and active the first is, the sooner will the latter occur, be more violent, but of shorter duration, than when the light is languid and dull.

VII. On the Manner in which White Marble is produced. By R. S. Raspe, F.R.S. An Abstract from the Latin, p. 47. (1770)

The Philosophical Transactions of the Royal Society of London, For their commencement, in 1665, to the year 1800: Abridged, with notes and biographic illustrations by Charles Hutton, LL.D. F.R.S. George Shaw, M.D. F.R.S. F.L.S. Richard Pearson, M.D. F.S.A. VOL XIII From 1770 to 1776. London: Printed by and for C. And R. Baldwin, New Bridge-Street, Blackfriars. 1809In this paper "Mr. R. gives an account of some observations made by the Abbé Vegni on the hot mineral waters of St. Philip, situated at Radicofani, in Tuscany, on the road from Florence to Rome. 1° The Abbé traced the source of «hese waters to a small bill (which appeared to be entirely composed of white marble), from which they flowed in several rivulets. 2° He found that these waters abounded in sulphur. 3° He found that they deposited a great quantity of shining white tophus, with which not only the sides of the channels, along which they flowed, became incrusted, but likewise all kinds of hard bodies that were thrown into them; and this in such manner, that when the said tophus was dexterously broken off, it retained exactly the form and shape of the bodies on which it had been deposited. 4° He furtlier observed, that when the old channels became choked up by - the accumulation of tophus, or in any other manner, the water still continued to deposit tophus in its new and more elevated channels.

Hence the Abbé was led to infer, 1° That the whole of that hill, from which these hot mineral waters issued, was formed by the successive deposition of this shining white tophus. 1° That this tophaceous precipitate might be rendered subservient to the arts, provided it was caught upon moulds. Accordingly the Abbé set on foot an undertaking of this kind, which succeeded very well. Models of various kinds of sculpture formed of gypsum, well varnished and be smeared with oil or grease, being placed in the currents of these hot springs, became incrusted with tophus to the thickness of 1 lines -m the space of 6 days; and in this manner were obtained bas reliefs, medallions, architectural ornaments for doors, windows, chimneys, &c. which in many instances looked like real sculpture, and seemed to be formed of the purest Carrara marble.

Mr. Raspe adopts the opinion that all white marble is a precipitate from water like the tophus of the hot springs above mentioned.

XXXIX. Continuation of an Experimental Inquiry concerning the Nature of the Mineral Elastic Spirit, or Air, contained in the Pouhon Water, and other Acidulæ. By W. Brownrigg, M. D., F. R. S. p. 357. (1774)

The Philosophical Transactions of the Royal Society of London, For their commencement, in 1665, to the year 1800: Abridged, with notes and biographic illustrations by Charles Hutton, LL.D. F.R.S. George Shaw, M.D. F.R.S. F.L.S. Richard Pearson, M.D. F.S.A. VOL XIII From 1770 to 1776. London: Printed by and for C. And R. Baldwin, New Bridge-Street, Blackfriars. 1809

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* Now termed Carbonic Acid Gas.Prop. 1. The ferruginous and absorbent earths, contained in the Pouhon water, are kept dissolved in it, by means of the mephitic air* to which those earths are united. — In an inquiry concerning the nature of the mineral and elastic spirit, or air, contained in this water, published in the Trans, of the r. s., vol. lv. [Abrid. vol. xii, p. 235 J it has been shown, that when the Pouhon water is excluded from all contact with the common air, in such manner that the mephitic air which it contains has free liberty to fly from it into an empty bladder, this air does not separate from the water by any spontaneous motion, as it would from its rare texture and elastic force, were it at liberty to exert these its qualities: but, on the contrary, in this situation, it remains united to the other ingredients of the water, when exposed to the most intense heat that we usually observe, in the open air, in this our climate. It has been further shown, in the 2d experiment, that this elastic fluid, when excluded from common air, in the manner before related, is but slowly expelled from the Pouhon water by a heat of 110 degrees of Fahrenheit's ther mometer, though such heat is sufficient to raise water, a much heavier body, in distillation: and so closely is air united to the other ingredients of the water, that it is not wholly expelled from them by a scalding heat of 160 or 170 degrees of the scale, when exposed to it for 2 hours.

Which experiments therefore prove, that this air is not detained in the Pouhon water by the pressure of the atmosphere, or by any other external force, as is the air with which beer, or other fermenting liquors, are often surcharged, while they are confined in bottles; but that this elastic fluid is equally mixed with the watery element, and with the other ingredients of which this mineral water is composed, and exists with them in a state of solution, or in a fixed state, being attached to the water, and to the other ingredients dissolved in it, by a force sufficient to keep them all united together in one uniform compound, while this force is not removed by some external cause.

It further appears, from the same experiments, that so long as this air continues united to the other ingredients of the Pouhon water, its martial and absorbent earths do also remain suspended in it; but, so soon as any part of this air is expelled by heat, those earths begin to separate from the water, which then becomes white and turbid; and when, by continuance of the heat, more of this air is expelled, more of the earthy particles also separate from the water, in the same proportion as its air is separated from it; and while only a small portion of the air remains, some portion of the martial earth also remains dissolved in the water, as appears from its giving a slight tinge of the purple, when mixed with galls: but none of these earths are any longer detained in the water, than while it continues impregnated with some mephitic air: when this air is entirely separated from the water, it is wholly decompounded, having lost its distinguishing brisk and pungent taste, and its power of striking a purple colour with galls; its more volatile and elastic principles being exhaled, its metalline and absorbent earths then subside in a white flocculeht sediment, and no other substance remains dissolved in the water, save only the small portion of alkaline and neutral salts, which enter its composition.

From this short recapitulation of the abovementioned experiments, it therefore appears, that the Pouhon water undergoes a decomposition when its air is expelled from it by means of heat. The opposite extreme of cold is also found to produce the same effect of decompounding the Pouhon water, when this its aerial principle is expelled from it by means of congelation. For having poured some of this water into open tin vessels, that were placed in the common freezing mixture of sea salt and snow, as soon as the water began to shoot into ice, at the bottom and sides of the vessels, very minute bubbles of air incessantly arose in it, and were discharged from its surface with such force, as to carry with them small particles of the water to a considerable height; and continued thus to fly off, till all the water was congealed. The ice was very white, from the minute bubbles ef air, which were every where interspersed through it, and by which the frozen water considerably increased in bulk, so as to rise at its surface into a very convex form. The water, when thawed, was white and turbid, and soon let fall its metallic and absorbent earths in a white sediment, it then had almost lost all its taste; and, being mixed with tincture of galls, only gave a slight purple tmge. By a 2d congelation, it seemed almost entirely deprived of its air, and, with it, of the remaining part of its white earths; and, when decanted from its sediment, no longer struck a colour with galls. From these experiments it therefore appears, that as soon as this water is deprived of its air, whether it be by heat or by cold, it is no longer capable of keeping those earths dissolved, which, while it is impregnated with this air, continue suspended in it.

In these decompositions of the Pouhon water, by heat and by cold, no volatile spirit, either acid or sulphureous, nor any other subtile matter, has been found to fly from it, save only its mephitic air: while this air is present in the water, its martial and absorbent earths remain dissolved in it; as soon as this air is separated from the water, in whole or in part, those earths, either in the whole or in part, do also separate from it, and are no longer suspended in it, than while they are united to a due proportion of this aerial solvent. Whence it appears, that this mephitic air is the medium by which the metalline and absorbent earths, contained in the Pouhon water, are held in solution; and, contrarywise, that those earths are the medium, by which this air is more firmly united to the watery element in this compound, in which it enters as a principal ingredient, and, by its solution in the water, and its union with these earthy substances, from a very rare volatile and elastic body, is reduced to a fixed state.

This dissolving power of mephitic air may further be proved from the recomposition of the Pouhon water, by adding to it the air expelled from it by coction. But as Mr. Cavendish has already shown, that the absorbent earths of Rathbone Place water may be redissolved by the mephitic, or fixed air, which had been extracted from that water; and as Mr. Lane has also demonstrated, that iron is rendered soluble in water., by the medium, of mephitic air, Dr. B. did not think it necessary at that time to give an account of his experiments on the same subject; but as those experiments contain some phenomena that have not yet been noticed, he may perhaps offer them to the public on some future occasion.

Schol. 1. — From the foregoing experiments, it appears that the mephitic air and martial earth, contained in the Pouhon waters, strongly attract each other, and, uniting together, form a concrete soluble in water, and readily distinguished in it, by the peculiarly brisk acidulous taste, which it receives from this aerial principle, joined to a rough subastringent taste, which proceeds from the iron. This concrete, like other vitriols of iron, strikes a black colour with galls, and may well be esteemed a saline body of the neutral kind, of which the mephitic air constitutes the spirituous solvent, and the martial earth its base. It further appears, that the mephitic air is possessed of all the properties, by which some of the chemists have distinguished those pure and simple bodies, or spirits, which by them are esteemed, in their own nature, and of themselves, saline, and which, in union with ether bodies, form salts that are more compound. For this aerial solvent, in like manner with the pure acid spirits, is soluble in water, and imparts to it its peculiar sharp and acidulous savour: also, in combination with various metalline and absorbent earths, this volatile elastic spirit, like those acids, forms various saline concretes of the neutral kind; inasmuch as those metalline and absorbent earths, when united to this elastic spirit, are thus rendered soluble in water; and, in union with it, acquire peculiar savours, . resulting in part from this their spirituous principle, and in part also from the particular kind of earth with which it is combined. This air therefore, considered in the relation which it bears ot several earthy substances, and to water, considered also as it impresses the organs of taste, with its peculiar brisk, and acidulous savour, may justly be stiletl a mineral elastic spirit of a saline nature, and is sufficiently distinguished from all other saline spirits, by its great rarity, and by its aerial nature. How far, and under what laws, this relation between mephitic air and various saline earths, and other bodies, may be extended, has not yet been fully discovered: suffice it in this place to remark, that a class of saline bodies of a neutral nature are here detected, composed of various earthy bases, united to a volatile aerial spirit, all of which agree in one common solvent, the mephitic air, but differ from each other, according to the nature of the base to which this air is united.

The agreement of these saline concretes with neutral salts in these essential properties, by which these last are distinguished from other more simple saline bodies, will further appear from their decomposition; which is effected by those various ways, and under the same laws, by which all other neutral salts are decompounded; namely, by all those different ways, by which the acid spirits, and the terrene or alkaline bases of neutral salts, can be separated from each other.

For, first, the aerial spirit of these saline concretes, is forced, by fire, from its union with the earthy base, which it holds dissolved in water, in like manner as the acid spirit of other neutral salts are expelled by fire from the more fixed principles, which enter the composition of those salts. The degree of heat required to separate the acid spirit of neutral salts, from their more fixed alkaline or earthy base, varies in the decomposition of almost every different kind of salts; and the extreme volatility and expansive force of this aereo-saline principle renders it more easily separable, by heat, from the fixed principles to which it unites, than any other kind of saline spirit.

Secondly. The saline concretes, formed with this aerial solvent (in like manner as other neutral salts), are decompounded by the addition of stronger acids, which more powerfully attract the terrene or metallic base of these concretes, than it is attracted by their light and subtle aerial spirit, and detaches from them the aerial solvent to which tho?e earths were before united. All acids, found in a liquid form, have this effect from the light vinous acids to the most ponderous acid of vitriol; so that the affinity between these metalline and absorbent earths, and this their aerial solvent, is less than that which exists between the same earths and all the known acid spirits. In all additions of these acids to the spirituous or acidulous waters, an effervescence has been observed, not readily accounted for, by those who suppose an acid to predominate in those waters. The conflict and discharge of air here arises from the expulsion of the aerial principle from its terrene base; in like manner as the acids of sea salt and nitre are expelled, with effervescence, from their alkaline bases, by the more powerful acid of vitriol. And here, by the way, it may be proper to remark, that the vitriolic acid, when mixed with the acidulae and other chalybeate waters, does not preserve those waters from decay, as Hales, and others, after him, have supposed; but, on the contrary, destroys their texture, or decompounds them, by expelling their elastic spirit, and entering into new combinations with their earthy priiv ciples; thus forming a new compound, less perishable indeed than the former, but also less efficacious in the cure of many diseases. When Rhenish wine is added to the acidulae, the large quantity of air that flies off may, in part, proceed from the wine; but when Dr. B. mixed the vitriolic acid with Pouhon water, a considerable quantity of air was indeed discharged; but not the whole which that water holds in solution. He therefore conjectured, that some part of the air, contained in that water, might be imbibed by the superabundant acid, which he used in the experiment, and that more mephitic air might perhaps have been expelled from the water, had he only mixed with it the exact quantity of this acid, that was required to dissolve the earthy substances contained in it.

Thirdly. These saline concretes, contained in the Pouhon water, and other acidulae, are subject to decomposition, not only from acids, as before related; but also from alkalies, whether fixed or volatile: all which more powerfully attract this subtile aerial principle than it is attracted by the martial and absorbent earths, to which it is united in those waters. And here again appears an exact agreement between these aereo-saline concretes, and various neutral salts, in the mode of their decomposition. For the ammoniacal salts (which are all composed of the volatile alkali, united to an acid spirit, either muriatic, nitrous, or of some other kind) as soon as one of the fixed alkalies, or quicklime, is added to any of them, the acid spirit which it contains, quitting its union with the weaker volatile alkali, this last is let loose; and the stronger alkali, or quicklime, takes its place; between which and the acid spirit a new combination is formed. The same happens when any alkali, either fixed or volatile, is added to the acidulae; their elastic spirit then quits the ferruginous and absorbent earths, to which it was joined, and forms a new combination with the alkali, by which it is more powerfully attracted than by these earthy substances. These earths therefore, being no longer suspended in the water by the aerial solvent, render it turbid and milky, until they have gradually subsided in it, in the form of a white sediment: for such is the native appearance of the martial earth, as well as of all the other earths contained in these waters, as will be shown here after. In these decompositions of acidulous waters, by means of alkalies, no effervescence, or discharge of air bubbles, takes place; for here the air is all absorbed by the alkali added, and not expelled from the water, as it is in the decomposition of the same waters, by means of stronger acids.

When the acidulae are mixed with common soap, a two fold decomposition takes place. The fixed alkali, quitting the unctuous substances, to which it was joined in the soap, unites itself to the aerial spirit, or mephitic air, of those waters, while this air, at the same time, deserts the earthy substances with which it was before combined. The same new combinations seem to take place, when soap is mixed with any of those waters which are usually called hard; many of which waters have been found to contain an earthy substance, dissolved by means of this subtile aerial principle.

The above observations and experiments show an exact agreement, in the several ways by which the various neutral salts, and those saline concretes, formed of mephitic air united to an earthy base, are decompounded. It ought however here to be remarked, that the saline concretes, which exist in the Pouhon water, in a dissolved state, though evidently of the neutral kind, have not hitherto been obtained in a solid form; owing perhaps, in some measure, to the great volatility of their spirituous principle; but chiefly to their being subject to decomposition, from the precipitation of their earthy base, by means of common air, during the evaporation of the water in which they are dissolved, as will be shown hereafter.

The mephitic air of the acidulae, though it is soluble in water, and imparts to it its brisk and pungent taste, which has been usually stiled subacid; and though it produces effects exactly similar to those of acid spirits (by readily uniting to various earthy substances, which of themselves are not soluble in water, but, by their union with this aerial fluid, are rendered soluble in it, and communicate to the water peculiar savours, and form in it saline concretes of the neutral kind; which concretes, so formed, are again separable into their component ingredients, by all those ways by which the acid and alkaline principles of other neutral salts are separable from each other) yet it differs from all acid spirits, found in a liquid form, in its rare texture and in its elastic quality, and in not striking a red colour with syrup of violets, and other blue tinctures of vegetables; which change, in the blue colour of those tinctures, is usually esteemed a test of the presence of an acid. Besides the trials which have been made, by mixing syrup of violets with pure water, impregnated with various kinds of mephitic air, in which no change in the colour of the syrup was observed, he had for several days suspended pieces of linen, that had been dyed blue with fresh juice of violets, in the mephitic air of spa water, and also in that of chalk; and, when the linen was taken out of the said air, did not perceive its blue colour in any wise changed, though the same pieces of dyed linen were instantly turned of a green colour, when exposed to the fumes of spirit of hartshorn. Whether therefore, and under what relations, this aereo-saline spirit may merit the title of an acid, he leaves to the determination of others. Such however it has appeared to be to many philosophers, since this mephitic air is doubtless the same with the acidum vagum fodinarura of Boerhaave and others; and with the acidum centrale perpetuum inexhauribile of Beccher; with the spiritus sulphureus aereo-aethereo-elasticus of Hoffman; and the sal embrionatus and sal esurinus of the sagacious Helmont, which, he says, corrodes the ore of iron, and with it forms a volatile vitriol in the Pouhon water. All these, and many other philosophers, had acquired some knowledge of this subtile aereo-saline principle from contemplating its effects; but, not having obtained it in a palpable form, were unacquainted with several of its principal properties.

From considering the great subtilty of this aereo-saline principle, its power of dissolving many earthy substances, with its property of uniting readily towater, and with it, of pervading the very minute vessels of the animal frame, without injuring them, as stronger acids do by their corrosive quality, we may thence form some judgment of the great efficacy of this air, as a de-obstruent and solvent, in many diseases of the human body, arising from preternatural concretions and obstructions thence ensuing. If to these we add the geat antiseptic powers of this kind of air, which it possesses in common with acids, and which were first detected by Sir John Pringle, and have since been more fully explained by Mr. Macbride and Dr. Priestley; we then, in some measure, may account for those extraordinary effects which this kind of air is found to produce, in the cure of many obstinate diseases, with which mankind are afflicted.

LII. Of a Pure Native Crystallized Natron, or Fossil Alkaline Salt, found in the Country of Tripoli in Barbary. By Donald Monro, M.D., F.R.S., &c. p. 567 (1771)

The Philosophical Transactions of the Royal Society of London, For their commencement, in 1665, to the year 1800: Abridged, with notes and biographic illustrations by Charles Hutton, LL.D. F.R.S. George Shaw, M.D. F.R.S. F.L.S. Richard Pearson, M.D. F.S.A. VOL XIII From 1770 to 1776. London: Printed by and for C. And R. Baldwin, New Bridge-Street, Blackfriars. 1809

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* See an account of the making of glass with nitre and sand in C. Plinii Secundi Hist. Natural, torn. ill. lib. xxxvi. cap. 26, and an account of its medicinal virtues, ibid. lib. xxxi. cap. 10. And Tacitus, in mentioning the river Belus in India, says, 'Circa cujus os collectae arenee, admixto nitro, in vitrum excoquuntur.' Lib. v. Mist. sect. 7. — Orig.

** Nitre is mentioned as used in baths, in several parts of the Holy Scripture, particularly by the prophet Jeremiah. See chap. ii. ver. 22. The nitre, or natron, is likewise taken notice of by many other of the ancient authors. — Orig.

*** See his notes on title 26, p. 86, of the edition printed at London l684-5. — Orig.It is well known that the nitre, or nitron, of the ancients, which they used for making of glass,* and in their baths,** and for other purposes, was not the salt which now goes by the name of nitre, or saltpetre; but a salt of an alkaline nature, which at present is commonly called the natron of the ancients, or the fossil alkali. The knowledge of it was entirely lost for several centuries; but was revived in the last, by the Hon. R. Boyle, who, in his Short Memoirs for the Natural Experimental History of Mineral Waters,*** after telling us that it is of an alkaline nature, says, 'that he had some of it brought from Egypt, and a neighbouring country, whose name he did not remember.'

However, it was afterwards neglected, and its properties as a distinct species of alkaline salt not known for many years; for though chemists observed, that a Glauber salt and cubic nitre were formed by dislodging the marine acid from sea-salt, by means of the vitriolic and nitrous acids; and from thence suspected that there was something particular in the basis of this salt; yet its true nature was not discovered till Mons. du Hamel du Monceau gave an account, in the Memoirs of the French Royal Academy of Sciences for the year 1736, of his having obtained it pure, in two different ways. 1st. By dislodging the marine acid by means of the vitriolic, and then separating it by the addition of a phlogiston, and forming a hepar sulphuris, from which he precipitated the sulphur by means of the vegetable acid, and then separated this acid from the basis of sea-salt by the force of fire. 2d. By dislodging the marine acid from the seasalt by the addition of the nitrous, and so forming a cubic nitre, from which he dislodged the acid, by deflagrating it with charcoal; and then he purified the remainder by dissolving it in water, and by filtrating and evaporating the liquor and crystallizing the salt.

After he had obtained the basis of sea-salt quite pure, he tried a number of experiments with it, and with the natron of Egypt; and found that they were entirely of the same nature, and that they were of a distinct species of alkaline salt, different in their properties from the potash, and other alkaline salts, commonly obtained by burning wood, and most other vegetable substances; and that they formed different neutral salts with the 3 mineral acids, and with the vegetable. This salt is likewise got from burning the barilla, the kali, and other marine plants; and all that is at present used in this country, by our manufacturers, has been prepared in this manner.

* See Hoffman, Phys. Chem. lib. ii. obs. 1. Geoffroy, Mater. Medica, part i. cap. 2. Dr. Shaw's Travels, Excerpt, p. 55, and other authors. — Orig.Hitherto it has not been found native in the western parts of Europe, except in mineral waters, and in the neighbourhood of volcanos, or at places where they are alleged to have existed formerly; but it has long been found in Egypt, and near Smyrna, and in other eastern countries, commonly mixed with earth, in a floury or concrete form; in some places pretty pure, in others more mixed.*

In the year 1764, Dr. Wm. Heberden gave an account of a salt of this kind, found on the Pic of TenerifF, where there is a volcano; and added several very ingenious experiments of the Hon. Henry Cavendish, to prove that the vegetable alkali has a greater affinity with acids than the fossil or natron. It is probable that this salt, got at the Pic of TenerifF, is the basis of sea-salt, whose acid has first been dislodged, either by the force of fire, or by the acid of decomposed sulphur, which has afterwards been attracted by a fresh phlogiston, and both separated bv the force of fire; though it is not at all impossible but that there may be magazines of this fossil salt lodged native in the bowels of this mountain.

Hitherto there had been no account of its being found any where native in a crystalline form, and in large quantity; and therefore he imagined that the following history would be agreeable to the b. s. In the year 1765, Mrs. White, widow to the late consul White of Tripoli, on her return to this country, showed Dr. D. M. a substance which, she said, had a very particular property of bubbling up, or fermenting, when mixed with lemon juice. Immediately, on seeing and tasting it, he suspected it to be a pure native natron, or fossil alkali; and was confirmed in this opinion, by mixing it with difFerent acids; and he afterwards had a few pounds of it sent home to him, and some gentlemen in the city had imported some hundred weight of it.

On inquiring into the history of this salt, he was told that it was brought yearly to Tripoli, in large quantities, from the mountains in the inland part of the country, and that it went by the name of Trona; that the inhabitants sometimes took an ounce, or more of it, by way of physic, and that it commonly operated both as an emetic and purgative medicine; that the principal use they made of it, was to mix it with their snufF, to give it, what they think, an agreeable sharpness; and that it was yearly sent to Constantinople, in Urge quantity, to be employed for the same purpose. But so far as he could learn, the Turks are entirely ignorant of its nature, and employ it for no other uses. It is well known that this salt does not run per deliquium, but falls down into a white floury powder, when exposed to the air; and that it makes a harder and firmer soap than the common vegetable alkali, and is alleged to make a purer and finer glass.

This salt, which he had the honour to present to the r. s., was extremely pure, dissolved entirely in water, leaving only a small quantity of a reddish earth be hind. He tried what quantity of acid I 02. of this salt would saturate, and found that it saturated as much as near 2-l oz. of the common gross barilla, in the form it is commonly imported. He had it likewise tried by calico printers, and it was found to answer all their purposes, and nearly in the same proportion with respect to the gross barilla, as above mentioned, and he was told that it was thought to answer better than any other salt they had ever tried. Most of the neutral salts made with this alkali and acids, except the cubic nitre, keep long without running per deliquium, even those made with vegetable acids; for most of the neutral salts made with vegetable acids, and with some of this salt, which he had the honour to present to the r. s. in the year 1 767, still remained entire, though kept only in a close drawer, in the same tea-cups and small basins, without any cover, as they were shown to the Society.

He had not been able to learn in what particular place of the inland part of Tripoli in Barbary this salt is found, nor how it is disposed of in the bowels of the earth: but it should seem to run in thin veins, of about 4 an inch, or a little more thick, in a bed of sea-salt; for all of it that has hitherto been imported into this country, is covered with sea-salt on each side. The one side is always smoother than the other, and appears as if it had been the basis on which it rested; the other, which should seem to be the upper side, is rougher, by the shooting of the crystals. The pieces of the thin veins appear almost as if the salt had been dissolved in water, and afterwards boiled up into thin crystallized cakes, only that the crystals are much smaller, and disposed in a manner that cannot easily be imitated by art; for when this salt is dissolved, and evaporated to a pellicle, and left to crystallize, it always shoots into crystals resembling those of Glauber salt.

Brown paper dipt into a solution of this salt, after it is dry burns almost as if it had been dipped in a solution of true nitre, as Dr. Heberden had observed of the salt got at the Pic of Teneriff; which shows that it contains more of an inflammable principle than the common vegetable alkali. There are great mines of sea-salt in the country of Tripoli, the salt of which should seem to contain a large proportion of this natron; for he was told that all the meat salted with it acquired a red colour.

This native alkaline salt having never been subjected to the force of fire, is perfectly mild, and contains no caustic parts, as the barilla, and the common potashes prepared by burning wood and plants, or the salts thrown out by volcanos commonly do; and therefore it will be found to be much more useful for bleaching and washing linens, and for clearing and scowering cotton or woollen stuffs, and for many other purposes, than any other alkaline salt hitherto known, at the same time that it will answer every purpose for which the other kinds of the fossil alkali are employed.

When this salt is to be used for making rochelle or other neutral salts, or for washing or bleaching linen, it ought first to be dissolved in pure water, and the solution be allowed to stand for some time, till the reddish or brown earth has all precipitated to the bottom, and then the pure liquor ought to be poured off, and what remains at the bottom be thrown into a filter; for if this precaution is not taken, the reddish earth is in danger of giving a slight brown or reddish colour to the neutral salts, or to affect the colour of the linen.

XXV. Letter from Mr. John Baptist Beccaria, of Turin, F. R. S., to Mr. J. Canton, F.R.S., on his New Phosphorus receiving Several Colours, and only Emitting the Same. From the Latin, p. 212. (1771)

The Philosophical Transactions of the Royal Society of London, For their commencement, in 1665, to the year 1800: Abridged, with notes and biographic illustrations by Charles Hutton, LL.D. F.R.S. George Shaw, M.D. F.R.S. F.L.S. Richard Pearson, M.D. F.S.A. VOL XIII From 1770 to 1776. London: Printed by and for C. And R. Baldwin, New Bridge-Street, Blackfriars. 1809Mr. B. made several cylindrical boxes of thin iron plates, black withinside; and covered with a lid; in which was inserted a glass of any colour different from that of the box. Into every box he put similar bits of the phosphorus. These inclosed bits were exposed to the sun altogether; then taking the boxes into the dark, and opening them, he saw that the piece of phosphorus was green, which was imbued with the light through the green glass; but red, through the red glass; and yellow, through the yellow glass: that is, it appears by this experiment that the phosphorus emits not only the light imbibed, but each its own light also.

IX. Experiments on a New Colouring Substance from the Island of Amsterdam, in the South Sea. Made by Mr. Peter Woulfe, F. R. S. p. 91. (1775)

The Philosophical Transactions of the Royal Society of London, For their commencement, in 1665, to the year 1800: Abridged, with notes and biographic illustrations by Charles Hutton, LL.D. F.R.S. George Shaw, M.D. F.R.S. F.L.S. Richard Pearson, M.D. F.S.A. VOL XIII From 1770 to 1776. London: Printed by and for C. And R. Baldwin, New Bridge-Street, Blackfriars. 1809This substance is of a light bright orange colour; has a peculiar, though not: a strong smell; and, when handled, gives a yellow stam to the skin, which does, not readily wash out with soap: and water. Put on a red hot iron, it smokes, melts, and catches fire, leaving a caput mortuum. When boiled with water, it gives the liquor only a slight yellow tinge, which is but little heightened by the addition of a fixed alkali; therefore the colouring part of this; substance is insoluble in water. Oil of vitriol put to it becomes of a red orange colour; but, when the acid is drained off, the residuum appears purple. Annotto, treated in the same manner, gives a blue colour. Spirit of wine, aether, fixed and volatile alkalies, as also soap, dissolve the colouring part of this substance. To determine the quantity of colouring matter which it contains, 2drs. were digested in a mattrass, with 4 oz. of rectified spirit of wine; the solution, being filtered, assumed a rich deep yellow colour, like a strong solution of saffron or gamboge with the same spirit; what remained in the filter was digested a 2d time, with 4 oz. of fresh spirit of wine, and the liquor filtered; this solution was much weaker than the first. The undissolved part remaining in the filter after this 2d solution was digested, a 3d time, with 4 oz. of fresh spirit; but the solution was now quite weak, and of a very pale yellow colour. The residuum being now deprived of its colouring portion, was slowly dried, when it appeared of a very pale yellow colour, felt as soft as starch between the fingers, and weighed 42 grs.; so that nearly 2/3 of this colouring substance are soluble in spirit of wine; the undissolved part is not soluble in water, acids, or alkalies. Put on a red hot iron, it smokes and catches fire without melting, leaving a caput mortuum, and gives a smell similar to that arising from common vegetable matter. The first solution in spirit of wine, after standing 24 hours, deposits some of its colour in the form of minute spiculine crystals, of an orange colour. The 2d and 3d solutions let fall none of their colour. The 1st solution, dropped on paper, tinges it of a bright orange colour, the 2d gives a lively yellow colour, and the 3d a pale yellow. The 1st solution, sufficiently diluted with spirit of wine, makes a bright yellow stain on paper, no way inclining to an orange, but exactly resembling that made by the 2d solution; hence it seems probable, that an orange colour is only a deep yellow. Vitriolic aether readily dissolves the colouring part of this substance, and affords solutions of nearly the same colour as those made with spirit of wine. Oil of turpentine dissolves but a small portion of it, and acquires only a pale yellow colour. A solution of fixed alkali in water, digested with this substance, dissolves a large portion of its colouring part, and the solution is of a brownish yellow colour. Volatile spirit of sal ammoniac, seems to dissolve a larger portion of it than the fixed alkali, and the solution is of a reddish orange colour. A solution of soap in water, boiled with this substance, likewise dissolves its colouring part. All the foregoing solutions, except that in oil of turpentine, which was not tried, dye silk, cloth, and linen, of various shades of yellow and orange; but these colours are discharged, by boiling the dyed substances for some time in soap and water. This colour can therefore be of use only in dying silk and wool, for which purpose we are already furnished with, good dyes. Few colours go so far in dying as this new substance, and none dye so speedily, especially when soap and water are used as the solvent; for a dip or two will dye cloth or silk of a lively yellow colour, when put into the mixture while hot. Soap and water may be perhaps used with advantage, as the solvent for several other colours.

From the foregoing experiments it appears, that this colouring substance, on -which they have been made, is of the resinous kind, and has a good deal of affinity with annotta.

IV. Experiments on Dying Black. By Mr. James Clegg, of Redivales, near Bury, p. 48. (1774)

The Philosophical Transactions of the Royal Society of London, For their commencement, in 1665, to the year 1800: Abridged, with notes and biographic illustrations by Charles Hutton, LL.D. F.R.S. George Shaw, M.D. F.R.S. F.L.S. Richard Pearson, M.D. F.S.A. VOL XIII From 1770 to 1776. London: Printed by and for C. And R. Baldwin, New Bridge-Street, Blackfriars. 1809Lime having been proved to increase the solvent power of water, on astringent vegetables, for medical purposes, Mr. C. was desirous of knowing if it would be equally useful in the art of dying black: to this end he made the following experiments.

Exper. 1. Four pennyweights of each of the following astringents, viz. galls, sumach, oak bark, bistort root, and logwood, were boiled during 10 minutes, in half a pint of pure river water; on mixing the decoctions with a saturated solution of martial vitriol, in the proportion of 1/3 of the solution to 2/3 of the decoction, they struck colours differently inclining to blackness, in the following order: viz. oak bark, bistort root, sumach, galls. He then boiled the same weight of all the astringents, in the same quantity of lime water, and on mixing them as above, the colours they produced were inferior to those with plain water, the astringency of the logwood, or whatever gives it the property of striking black with green vitriol, was entirely destroyed; it produced not the least blackness with any quantity of vitriol.

Exper. 2. Four pennyweights of each of the astringents above-mentioned, were tritured in plain water, and 4 others in lime water; the measures of water used were equal to those left, after boiling, in the last experiment; and, on being mixed with martial vitriol, as in the last experiment, the colours produced, by this means, were superior to those produced by boiling. Those tritured in lime-water were judged to be the deepest, which agrees with Mr. Henry's experiments; but we must again except the logwood, which gave no colour by trituration, more than by boiling in lime-water.

Exper. 3. All the above mixtures having been written with as inks, and exposed 6 months to the air; those boiled in lime-water had failed much; those tritured in lime-water, and in plain water, had faded a little; those boiled in plain water evidently preserved their colour best. On slightly rubbing the faded writings, with a fresh astringent liquor, they recovered their original blackness; by which it appears, that it was the astringent parts of those inks which had failed.

Does it not appear, by these experiments, that, though lime water tends to deepen the colour produced by some astringents and martial vitriol, it by no means adds to the duration of those colours; and as lime-water, either by trituration or coction, entirely destroys the property, in logwood, of striking black with martial vitriol, it can by no means be of service, in the black dye, where logwood is a material ingredient. Does it not also appear, that a slight boiling is preferable to trituration, for the purposes of dying, when a durable colour is wanted?

Having observed a solution of iron, in a vegetable acid, struck a deeper black, on mixture with an astringent, and produced its effects much more expeditiously, than a strong solution of martial vitriol; it occurred, that the iron, being more slightly combined with the vegetable acid than with the vitriolic, made it more easy for the astringent matter to decompound the former, and produce an ink; if this was the case, he suspected, that lime-water deepened the colour of astringent and chalybeate mixtures, not so much by its action on the astringent, as on the chalybeate, the lime uniting with the superabundant acid, and leaving the iron with so much of the acid, as is necessary for the formation of an ink, to be more easily attached by the astringent matter of the vegetable. But if this theory was well founded, it followed, from analogy, that any substance, which had a greater affinity with the vitriolic acid than iron had, would produce the same effect, in some degree, as lime. To determine this:

Exper. 4. He took 2 vessels, containing equal measures of a strong astringent liquor, composed of galls and logwood: into one vessel he put a small quantity of pearl ashes; the other remained as a standard. Pieces of linen and cotton cloth, after maceration in these liquors, were thrown together into a strong solution of copperas; they were soon after taken out, and washed in cold water; when dry, the pieces prepared in ashes were, all of them, much deeper than the others.

He made use of different kinds of pearl and pot-ashes, as well as of many kinds of astringents; the ashes had the same effect, whatever astringent was made use of, and the strongest alkali always produced the deepest colour; and though ashes, used with an astringent, always gave a deeper black, than the same astringent without ashes, yet logwood, which without ashes gave not so deep a colour as galls with them, gave a much deeper black than galls with the same addition. There was a remarkable difference, in this case, between lime and ashes, in their effect on logwood; with lime it gave no blackness; but with ashes, it produced a deeper black than any other astringent he made use of.

Being desirous of trying the duration of colours, produced by astringents, in which different quantities of pearl-ashes had been dissolved;

Exper. 5. In 2 pints of river water, he boiled 1 oz. of logwood, during 10 minutes; he then added half an ounce of Aleppo galls, and boiled them together 10 minutes longer; the liquor having stood to cool, was decanted off, and divided into 6 equal quantities. N° 1 remained as a standard; into N° 2 he put 6 grains of fine pearl-ashes; N° 3, 12 grains; N° 4, 18 grains; N° 5, 24 grains; N° 6, 30 grains: to 6 drops of each of these liquors, he added 2 drops of a saturated solution of copperas; N° 2 and 3 struck a deep black; N° 1 and 4 black, but inferior to 2 and 3; N° 5, a brown black; N° 6, brown.

From this experiment it appears, that N°5 and 6 were spoiled by an over proportion of ashes. Before seeing experiments, wherein it had been demonstrated, that a quantity of acid enters into the composition of ink, Mr. C. imagined the alkali decompounded the copperas too suddenly, and disengaged the iron faster than the astringent matter could unite with it. But most probably the alkali neutralized too great a portion of the acid. All these writings having been now exposed 6 months to the air, in N° 5 and 6 the blackness is quite destroyed; N° 4 is somewhat faded; N° 1, 2, 3, remain nearly as they were; N° 2 and 3 being still superior to the standard.

VII. Of the Roots used by the Indians in the Neighbourhood of Hudson's Bay to dye Porcupine Quills. By Mr. John Reinhold Forster, F.R.S. p.54 (1772)

The Philosophical Transactions of the Royal Society of London, For their commencement, in 1665, to the year 1800: Abridged, with notes and biographic illustrations by Charles Hutton, LL.D. F.R.S. George Shaw, M.D. F.R.S. F.L.S. Richard Pearson, M.D. F.S.A. VOL XIII From 1770 to 1776. London: Printed by and for C. And R. Baldwin, New Bridge-Street, Blackfriars. 1809Among the curiosities presented by the Hudson's Bay Company to the b. s., is a small parcel of porcupine quills, dyed by the wild natives, some red and some yellow, with the roots of some plants they use for that purpose. Mr. F. examined them carefully, and found that they are probably of the same kind with those mentioned by Prof. Kalm, vol. 3, p. 14, and 160 of the English translation. The one root, dying yellow, is called by the French in Canada, Tisavoyanne jaune; the other, dying red, has the name of Tisavoyanne rouge. Prof. Kalm declares the latter to be a new plant, belonging to the genus of galium, and received by Dr. Linnaeus in his Species Plantarum, p. 153, by the specific name of tinctorium, on account of its dying quality. It grows in woody, moist places, in a fine soil. Kalm observes, 'that the roots of this plant are employed by the Indians in dying the quills of the American porcupine red, which they put into several places of their work: air, sun, and water, seldom change this colour. The French women in Canada sometimes dye their cloth; red with these roots, which are but small, like those of the galium luteum or yellow bedstraw.' Dr. Linnaeus describes this plant, as having 6 narrow linear leaves at each knot of the stem, and 4 at the branches; commonly 2 flowers are on each stalk, and its seeds are smooth. The roots, when dry, are of the thickness of a crow quill, brown on the outside, and of a bright purple red, when broken, on the inside.

The 2d plant, or the Tisavoyanne jaune, is, according to Prof. Kalm, vol. 3, p. 160, 'the three-leaved hellebore (helleborus trifolius Linn.); grows plentifully in woods, in mossy, not too wet, places. Its leaves and stalks are employed by the Indians to dye yellow several kinds of their work, made of prepared skins. The French learned from them to dye wool and other things yellow with this plant. Among the roots sent as a specimen from Hudson's Bay, Mr. F. found! several leaves, which he separated, and found the plant undoubtedly to be the three-leaved hellebore. In the 4th vol. of Dr. Linnaeus's Amoenitates Academicae, is a figure of this plant, which on comparison Mr. F. found by no mean* to be accurate: for the leaves in our specimens, and in those collected by a gentleman who favoured him with the sight of the plant, are far more pointed, than in the engraved figure. The stalks have constantly but one flower.

The dyed porcupine quills sent along with the roots from Hudson's Bay, are of the brightest red and yellow: and this circumstance suggested the thought of trying whether these roots might not be usefully employed in dying. For this purpose, he boiled a piece of flannel in a solution of half salt of tartar and half alum: the wet flannel was put into the decoction of the three-leaved hellebore roots, and boiled in it for the space of about 12 or 15 minutes; the flannel, when taken out, was dyed with a bright and lasting yellow dye. A white porcupine quill, boiled in the same decoction, became nearly of as bright a yellow, as those sent over from Hudson's Bay. This experiment made him believe that he had hit upon the right method of dying with the three-leaved hellebore; and will, he hopes, prompt the directors of the Hudson's Bay company to order larger quantities of this root from their settlements, as it will no doubt become a useful article of commerce.

The flannel, boiled in salt of tartar and alum as above mentioned, was likewise immersed and boiled for nearly the same space of time as in the former experiment, in a decoction of the root of the galium tinctorium, but it would dye only a dull and faint red. A porcupine quill boiled with it became yellow, but by no means red. This operation convinced him, that the Indians must certainly have some method to extract the bright and lasting colour, which he could not do. They use perhaps the root quite fresh, which circumstance probably makes them succeed in their dying process. If it could be brought about, to extract and afterwards to fix on wool the dye of this root, it would, no doubt, on account of its bright colour, be a valuable acquisition for our manufactures, and he does not in the least doubt of the probability of succeeding in the attempt, as the woollen stuffs are animal substances as well as the porcupine quills, and therefore easily susceptible of any dye.

The Spaniards of Mexico have but lately learned of the inhabitants of California, the art of dying the deepest and most lasting black that ever was yet known. They call the plant they employ for that purpose cascalote; it is arboreous, with small leaves and yellow flowers; its growth is still slower than that of an oak; it is the least corrosive of all the known substances employed in dying, and strikes the deepest black: so that, for instance, it penetrates a hat to such a degree, that the very rags of it are thoroughly black. The leaves of the cascalote are similar to those of the husiaoke, another plant likewise used for dying black with, but of an inferior quality. The latitude of California gives us hope that the country near the Mississippi, or one of the Floridas, contains this cascalote, the acquisition of which would be of infinite use in our manufactures.