Nicolas Louis Vauquelin’s Analysis of Prepared Tobacco
[12 Jan.–17 Apr. 1809]
Analysis of Snuff
of the Hôtel Longueville—By Mr Vauquelin.
In occupying myself in this research, my object was to know whether the principles discovered in the green Nicotiana also exist in the prepared tobacco; and if not, to find out what kind of change it undergoes. I also hoped to discover the substances employed in the preparation of snuff.
240 grammes of tobacco in powder washed five different times, with a litre of warm water each time, after dessication, weighed 105 grammes. It therefore lost in this operation 56¼ per cent, as well in humidity as in soluble matter—a quantity which is very considerable. The tobacco thus washed, had neither smell nor taste. Hence we may conclude, that it is in the soluble principles the properties of this substance are contained. It produced no effervescence with acids, which proves that it contained no insoluble carbonate.
When thrown on live coals, it emits a sharp smoke like that of wood, and which has no resemblance to that of unwashed tobacco.
We shall leave, for a moment, this residue, to occupy myself with the infusion of tobacco.
The first waters of the tobacco had an odor and smell like those of tobacco itself. They were alkaline, for they instantly re-established the color of turnsole reddened by an acid. We ought not1 to be surprised at this, when we recollect that in presenting to snuff a glass rod dipped in weak muriatic acid, white thick vapors are formed, doubtless occasioned by the combination of ammoniac with the acid.
The infusion of prepared tobacco differs then from that of the green plant in this respect, that the first is alkaline, and the other acid. This infusion precipitated abundantly a dissolution of silver in a substance which does not dissolve in the nitric acid, indicating that it contains a muriate.
Gall nuts occasion there a colored flocconous precipitate, which announces the presence of animal matter.
Lastly, potash developes a very sensible odor of ammoniac, and the oxalic acid proved that it contained lime.
The different infusions united were distilled in a retort until they were reduced to about ¹⁄₂₀. The liquor which passed over had at first no color, but in the course of some days it became slightly yellowish. Its taste was extremely acrid.
I had divided the products of this distillation to ascertain whether they presented some difference in their properties, but I perceived none that merit attention; except that the first contained carbonat of ammoniac, and were more colored than the last, of which the taste was stronger.
This taste was absolutely the same as that produced by tobacco when it falls into the throat.
The color of the infusion, thus concentrated, was singularly heightened, and the taste was thus insupportable by its acridness. Potash still developed from it the odor of ammoniac. During the distillation, the liquor had deposited a small quantity of brown dust, which appears to have proceeded from a portion of carbonated oil.
Having filtered the liquor, I continued to evaporate it by a gentle heat to the consistence of honey, and I treated the residue several times with alkohol, until it was no longer colored. There remained a brown matter viscous like thick mucilage. I leave this, for a moment, to continue the examination of the alkoholic dissolution.
The latter had a red brown color, and a taste extremely acrid: during the time of cooling, it deposited many needle-shaped crystals, which were found to be nitrat of potash.
The alkoholic liquor decanted from the crystals, was distilled to the consistence of syrop: the alkohol which passed over had not carried off an atom of the acrid matter; which proves that it is not volatile at the same temperature as the spirit of wine. The liquor remaining in the retort had preserved its acridness in all its force. This matter, thus concentrated, contained some portions of a thick oil, which was seperated by the addition of a little water and filtration. This oil well washed, had none of the acrid taste of the liquor from which it was seperated. In this state of concentration, caustic potash disengaged a strong odor of ammoniac, and produced in the same a flocconous precipitate. The nitrat of silver formed a precipitate which was the true muriat of silver. Lastly, the oxolat of amonniac occasioned therein a very abundant precipitate. It therefore contains muriat of ammoniac and muriat of lime.
Desirous to know whether the red brown color which this liquor had, was owing to a portion of the animal matter which had not been seperated by the alkohol, I poured into a portion gallic alkohol, and I obtained a yellowish precipitate. I filtered the liquor, which had then lost a great part of its color; and added a new quantity of gallic alkohol, which still formed a precipitate, but less abundant and less colored than the first. After a second filtration, the infusion of gall nuts always formed a precipitate, but was now white, and dissolved in an excess of gallic alkohol, and also in pure alkohol.
Having remarked that the last precipitate dissolved in alkohol, I wished to know if the first also dissolved therein, which I found to be the case.
The first precipitate formed by gall nuts in the dissolution of the acrid matter, had a yellow brownish color, as above mentioned. it dissolved for the most part in alkohol, which it colored with the same tint. There remained only an atom of a brownish substance in flacons. This precipitate dried was pulverulent. When kept for some time in the mouth, and moistened with saliva, it produced a strong acridness like that which the liquor2 itself occasioned. Exposed to heat in a crucible of platina, it exhaled as soon as warmed, vapors whose acridness was insupportable, which affected the eyes, and glided into the mouth, producing the same sensation as the liquor. When the matter began to decompose, it swelled in a singular manner, and left a very small portion of ashes.
This portion convinced me that the matter which communicated the color to the liquor in question, is not of an animal nature, which would have been extraordinary being dissolved in alkohol.
It appeared that in proportion as I added gallic alkohol to the liquor, its acrity diminished, and I suspected that the principle was itself precipitated and neutralized by the ; in consequence of which, I tried, by the same reactive, the distilled water of tobacco of which we have spoken above, and there was formed a white milky precipitate.
Fearing that the small quantity of the carbonat of ammoniac contained in this distilled water, was the cause of this effect, I saturated the alkali with some atoms of acid, and there was also a precipitate. I put, on the other hand, some drops of the carbonat of ammoniac in a glass of water, and I added thereto of the infusion of galls, but I obtained no precipitate. The mixture was not even troubled.
I saw that the presence of an acid, of carbonat of ammoniac, and of alkohol in this distilled water, prevented the gall nuts from there forming a precipitate.
Suspecting that the effect here produced by gall nuts was owing to a volatile oil, I put of3 this reactive in distilled rose water, and no effect was produced. On the other hand, I shook olive oil with this water, hoping that it would charge itself with the acrid principle, and that the water would become insipid, which did not take place; whilst it is known that the distilled water of plants yields to the fat oils their aromatic principle when produced by an essential oil.
This might lead us to suspect that the acrid matter contained in tobacco, is not of an oily nature.
The dissolutions of the nitrat of silver, of mercury, and of the acetate of lead particularly, are precipitated by the distilled water of tobacco; but fearing that the small quantity of carbonat of ammoniac contained in this, was not the sole cause of these effects, by means of a gentle heat I reduced a certain quantity of this water to about the twentieth part of its bulk, and although it was no longer alkaline, it always precipitated the metallic dissolutions in the same manner, the lead in large white floccules, the mercury of a yellowish color, which soon passed to gray; silver in a white matter which did4 not deposit, which only gave a milky half-transparent appearance to the liquor.
A portion of the infusion of tobacco thickened by distillation, and seperated by means of alkohol, exposed to the heat of a crucible of platina, also exhaled before boiling a gas of extreme acridity, which attacked the eyes, irritated the tracheal artery so as to excite a violent cough, and left for some time in the mouth the taste and odor of the smoke of tobacco: in proportion as the liquor concentered,5 the vapors became more abundant and stronger; and when the greatest part of the humidity was dissipated, the substance swelled, blackened, and inflamed: it left a coaly matter very divided, of which the washing gave alkali and muriat of potash. The charcoal thus washed and put in nitric acid produced a lively effervescence, and6 we obtained, by the evaporation, nitrat of lime in a considerable quantity. This matter then contained a salt with potash for its base, and another with lime. I suspect that it was the acetate of potash and muriat of lime, or perhaps the contrary.
All these experiments, which I multiplied and varied, appear to me to prove, that the matter which produced all the effects above-related, is a new vegetable principle of which the chemists have never spoken, which constitutes the essential and distinctive character of tobacco; and which does not perhaps exist except in this genus of plants; a principle very difficult to be destroyed, seeing it preserves itself notwithstanding the numerous operations to which the plant is submitted to bring it to a state of snuff—Operations which7 modify several other principles also found in this plant, as we shall soon see.
It will be recollected that I treated by alkohol the extract of the infusion, and that this reactive did not dissolve the totality of this extract; that, on the contrary, it left a considerable quantity of a brownish matter, and viscous like gum.
Of this matter we shall now examine the nature.
I dissolved it in water, and passed thereon acetate of lead, which occasioned an abundant brownish yellow precipitate, which, washed and diluted with water, was submitted to a current of sulphurated hydrogen gas. By this means the lead was converted to a state of sulphure. The liquor, filtered and concentered, was treated by alkohol to seperate the animal matter, and to obtain the malic acid. When we precipitate the malic acid, from any vegetable infusion whatever which contains an animal matter, by the acetate of lead, the malat of lead constantly carries with it a portion of this animal matter which colors it, and this matter is partly redissolved in the malic acid seperated by the sulphurated hydrogen. This acid, freed from alkohol, was considerably pure. The precipitate which it formed in the acetate of lead, redissolved entirely in the acetous acid, and the nitric acid converted it into oxalic acid. There exists then, in the prepared tobacco, malic acid as in the green plant. It has therefore not undergone any change by the preparation of tobacco.
Having ascertained, by experiments made on the infusion, that it contained a calcareous salt, I naturally supposed that the malic acid was combined with lime, and that consequently I ought again to find this earth combined with the acetous acid in the liquor precipitated by the acetate of lead.
To demonstrate the presence of the acetate of lime in this liquor, I began to precipitate of it a portion of the salt of lead which had been in excess by means of hydrogen sulphur. It was afterwards filtered and evaporated; but a fact which surprised me was, that a considerable quantity of malat of lime escaped the decomposing action of the acetate of lead, altho’ the latter was in excess. This salt, during evaporation, presented itself under the form of terrous crusts. The matter being dried, the residue was washed with small quantities of cold water; and I seperated by this means the acetate of lime from the malate of the same base.
I know not how to explain this effect. Is it owing to a portion of the malate of lime which, by some new combination, has eluded the action of the acetate of lead? Or is it produced by a portion of the malate of lead remaining in dissolution in the liquor, and of which the acid, made free by sulphurated hydrogen, shall have decomposed a portion of the acetate of lime, and have formed anew a malate of the same base? I am more disposed to believe in this latter manner of action; for after the lead is seperated by the sulphurated hydrogen, the acetate of lead precipitates a new quantity of malic acid. This proves at least, that the acetate of lead is not a very rigorous means of determining the quantity of malic acid contained in plants.
I found, as we see, in the infusion of tobacco in powder, the same substances as those which I had found in the juice of the green tobacco—to wit.—1o An acid principle. 2o An animal matter. 3o Malate of lime. 4o Muriat of ammoniac and of potash. 5o Nitrat of potash. 6o Acetate of potash. I moreover found carbonat of ammoniac and muriat of lime, which do not exist in the green tobacco: these two substances are probably formed there by the substances usually added to tobacco to make it stronger or sharper.
It is however possible that a part of the ammoniac, which is continually disengaged from the tobacco when it is in air, was produced during the fermentation of a portion of the animal matter of the plant, for I found this last singularly changed in snuff: it does not give a sufficient quantity of ammoniac by distillation.
Having several times washed the snuff with water, as mentioned above, I treated it warm by alkohol; but the latter gave, by evaporation, a sort of yellowish green resin, which had no bitter taste, and which was nothing else, as I believe, than the green resin of the plant changed in its color; for it had almost the same taste, and burned like it, and with the same odor. This experiment proves that water alone is sufficient to carry off from the tobacco all its acrid matter, and that this principle is very soluble in water.
The tobacco freed from every thing it contained Soluble in water and alkohol, had neither taste nor smell. A new proof that these properties reside in the soluble parts. Treated by a gentle heat with weak nitric acid, it communicated to the latter a deep brownish color. After 48 hours, the liquor was well expressed and filtered.
This liquor precipitated abundantly by the oxolat of ammoniac in a whitish gritty substance, which was oxolat of lime; the alkalis produced therein colored and flocconous precipitates. Nevertheless when the quantity of these acids was not sufficient to saturate completely the nitric acid, we obtained a gritty precipitate, which had the same appearance as that formed by the oxalat of ammoniac.
To know the nature of this precipitate, I operated, as I have said above, on a sufficient quantity of liquor, and I was convinced that the matter was calcareous oxalat. First, I boiled it with the carbonat of potash, and this first changed to a carbonat of lime: the potash saturated by the nitric acid gave the acidulous oxalat of potash.
Thus, there is no doubt that the prepared tobacco does not contain, like the green plant, oxalat of lime. Having also obtained from the liquor this oxolat of lime, I saturated it by ammoniac, and then there was formed a new precipitate, but more abundant than the first, colored and flocconous.
This precipitate distilled in a retort, furnished carbonat of ammoniac, fetid oil, and charcoal, which gave yellow ashes entirely soluble in nitric acid.
Ammoniac mixed with the dissolution occasioned an abundant precipitate, which was composed of phosphat of lime mixed with a little oxyd of iron.
Carbonated potash still determined a precipitate in the filtered liquor, and this precipitate was carbonat of lime, which proves that the nitric acid had retained a small quantity of the oxolat of lime, which was decomposed by heat.
It is even probable that the whole of the calcareous oxalat was not precipitated in the two above mentioned operations; for I am not sure that the oxalat of lime dissolved directly in the nitric acid, is not entirely precipitated by ammoniac, seeing that having added an excess of this alkali, if we pour in the oxalic acid, a precipitate is formed anew.
This then is not a good method to determine the quantity of oxalat of lime contained in vegetables, when extracted by the nitric acid.—The residue of tobacco washed successively by water, spirits of wine, and nitric acid, being burned, gave ashes consisting chiefly of silex: there were, however, traces of the phosphat and carbonat of lime, and of iron which escaped the action of the nitric acid.
I have then found in snuff the same substances above mentioned, which exist in the green tobacco, and this proves that they are not decomposed by the different operations they have undergone during the examination of the plant. I think, however, that the animal matter has experienced some small changes from which may result Carbonat of ammoniac: but I also found in the snuff muriat of lime, and carbonat of ammoniac doubtless proceeding from the addition of lime, or of the carbonat of lime and salt ammoniac, which are mixed with the wines to give them sharpness.
This tobacco, as well as the green vegetable that furnishes it, have presented nothing particular except the acrid principle above mentioned, and which I have not found in any plant that I have hitherto examined.
It is this principle that distinguishes tobacco from every other vegetable preparation with which it can be compared. According to the properties we have mentioned, we easily conceive how it so readily acts on the membrane of the nose, which it so irritates as to occasion violent sneezings, and dangerous sometimes for the persons not accustomed to it—How it occasions in the throat an insupportable acridity, and creates nausea and vomiting when it descends into the stomach—how introduced, by glyster, into the large intestines, it brings back [to]8 life by the irritation it produces, persons asphyxed by submersion, &c. In fine, this principle, which is soluble in alkohol, and in water, which is volatile, but not so much so as to prevent it from being centered in water, and especially in spirit of wine by a slow evaporation of its dissolutions, may be preserved, and employed to form an artificial tobacco with other vegetable powders, or to improve adulterated tobacco, or to give more force to that which is weak. To this principle concentered in water, we may give the name of essence of tobacco.—
MS (PPAmP: APS Archives, Manuscript Communications); in David Bailie Warden’s hand; undated; endorsed at the American Philosophical Society as “read 15 Sept. 1809.” Enclosed in TJ to Robert Patterson, 31 Aug. 1809.
Vauquelin’s two memoirs were presented to the members of the American Philosophical Society at its 15 Sept. 1809 meeting (APS, Minutes [MS in PPAmP]). On 16 Mar. 1810 a committee presented to the society its “Report relative to the Memoire of M. Vauquelin,” signed by Silvain Godon (PPAmP: APS Archives, Manuscript Communications). The committee observed that because “several periodical publications gave an account of the work,” it was uncertain whether Vauquelin still wanted his work published in the society’s transactions. It therefore directed Warden or Robert Patterson to ask Vauquelin if he would “present them again, with some new additions, which will restore to this piece a Character of originalness.” The society published neither memoir.
flacons: flagons. glyster or clyster is an enema or suppository (OED description begins James A. H. Murray, J. A. Simpson, E. S. C. Weiner, and others, eds., The Oxford English Dictionary, 2d ed., 1989, 20 vols. description ends ).
1. Manuscript: “not not.”
2. Manuscript: “liqor.”
3. Thus in manuscript.
4. Manuscript: “dit.”
5. Manuscript: “contentered.”
6. Manuscript: “and and.”
7. Warden here canceled “multiply.”
8. Omitted word editorially supplied.
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