A course of chemistry containing an easie method of preparing those chymical medicins which are used in physick : with curious remarks and useful discourses upon each preparation, for the benefit of such who desire to be instructed in the knowledge of this art / by Nicholas Lemery, M.D.

CHAP. XVIII. Of Vitriol.

VItriol is a Mineral compounded of an Acid Salt, and Sulphureous Earth; there are four sorts of it, the Blue, the White, the Green, and the Red.

The Blue is found near the Mines of Copper, in Hungary, and the Isle of Cyprus, from whence it is brought to us in fair Crystals, which keep the name of the Country, and are called Vitriol of Hungary, or Cyprus; it partakes very much of the nature of Copper, which renders it a little Cau∣stick; it is never used but in outward applications, such as Collyriums, or waters for the eyes, and to consume proud flesh.

White Vitriol is found near unto Fountains, it is the most of all depurated from a Metallick mixture: it may be taken inwardly to give a vomit; it is likewise used in Collyriums.

There are three sorts of Green Vitriol, the Ger∣man, English, and the Roman. That of Germany draws near unto the blue, and contains a little Copper, it is better than the rest for the prepara∣tion of Aqua fortis. That of England partakes of Iron, and is proper to make the Spirit of Vitriol. The Roman is much like the English Vitriol, ex∣cepting that it is not so easie to dissolve.

Red Vitriol was brought among us a few years ago out of Germany, it is called Natural Colco∣thar, and is esteemed to be a Green Vitriol Calcined by some subterranean heat. It is the least common of them all, it stops Bloud, being applied to He∣morrhagies.

If you dissolve a little white, or green Vitriol in water, and write with the dissolution, the writing will not be seen, but if you rub the paper with a little Cotton dipt in the decoction of Galls, it will appear legible; then if you wet a little more Cot∣ton in Spirit of Vitriol, and pass it gently over the paper, the Ink will disappear again; and yet at last if you rub the place with a little more Cot∣ton dipt in Oil of Tartar made per Deliquium, it will again appear legible, but of a Yellowish co∣lour.

The reason that I can give for these effects is this, the Spirit of Vitriol dissolves a certain Coagu∣lum which is made of Vitriol and Galls, but the Oil of Tartar breaking the force of this acid Spirit, the Coagulum recovers it self, and appears again, but because it now contains Oil of Tartar too, it acquires a new colour.

If you throw the dissolution of Vitriol, or Vitriol only powdered, into a strong decoction of dried

Roses, it will turn as black as common Ink; if you pour some drops of spirit of Vitriol into it, this Ink will turn red; and if you add to it a little vo∣latile spirit of Sal Armoniack, it will turn gray.

These changes of colour do proceed from the spirit of Vitriol's dissolving the Coagulum which the Vitriol it self had made, and rendring it invisible; the liquor recovers a fresher red colour than it had, before the Vitriol was put into it, because the same spirit does separate the parts of the Rose which were dissolved in the liquor, and renders them more visible.

The volatile spirit of Sal Armoniack, which is an alkali, does partly break the acid edges of the spirit of Vitriol, so that the parts of the Rose having nothing more to keep them rarefied, do close to∣gether, and consequently the liquor changes co∣lour.

By this experiment may be seen, that the dried Rose may serve to make Ink with, as well as Galls; Indian wood, and divers other things will do the same.

Gilla Vitrioli, or Vomitive Vitriol.

This operation is only a purification of white Vitriol.

Dissolve what quantity you please of white Vi∣triol, in as much Phlegm of Vitriol, as is needful to dissolve it; filtrate the dissolution, and evapo∣rate two thirds of the moisture in an earthen pan. Put the rest into a cool place for three days time, there will shoot out Crystals, which you must sepa∣rate;

then evaporate a third part of the liquor that remains, and set the vessel again in a Cellar, there will shoot new Crystals; continue thus eva∣porating and crystallizing, until you have gotten all you can; dry these Crystals in the Sun, and keep them for use; the dose is from twelve grains to a drachm, in Broth, or some other liquor.

Remarks.

This is only a Purification of Vitriol, that serves to separate a little earth from it.

All the liquor may be evaporated without any Crystallization, the Gilla Vitrioli will remain at bottom in a white powder.

White Vitriol is used in this operation rather than Green, because it is milder.

The other Vitriols may be purified after the same manner.

After taking this vomit, a man sometimes voids by stool a black matter like Ink, because it frequently happens that some part of the Vitriol descending into the Guts, meets a saline matter that it joyns with, and so causes a blackness, as it uses to do when Vitriol is mixed with Galls.

Calcination of Vitriol.

Put what quantity you please of Green Vitriol into an earthen pot unglazed; set the pot over the fire, and the Vitriol will dissolve into water; boil it to the consumption of the moisture, or else

until the matter turn into a grayish mass drawing towards white; this is called Vitriol Calcined to whiteness. If you should Calcine this gray Vitriol a good while over a strong fire, it would turn as red as bloud. It is called Colcothar, and is good to stop bloud, being applied to a wound.

Remarks.

You must not Calcine the Vitriol in a glazed pot for fear of dissolving the Vernish, which would change the nature of the Vitriol.

It may be Calcined, or rather dryed in the Sun, until it becomes white, this Calcination deserves to be preferr'd before the other, but only it is longer a doing.

The Vitriol may be likewise spread about a Fur∣nace heated a little, and so dried until it turns white.

If you should resolve to dry as exactly as you can, sixteen pounds of green Vitriol, there would remain but seven pounds of white Vitriol.

But in order to do this, you must powder the white mass of Calcined Vitriol, after you have broke the pot, and stir it a long time in an earthen pan, over a little fire, until there rises no more fume from it, or until there remains in it no more phlegm.

If you should Calcine this white Vitriol to a redness, you'd have five pounds and a half of Col∣cothar. The sulphur of Vitriol is lost during this last Calcination, you must do it in the Chimney, for the fume would be very injurious to the breast.

This sulphur has the same smell as ordinary sul∣phur.

Some have writ, that the red colour which ap∣pears after a long Calcination of English Vitriol, was an undoubted proof that there was Copper in it, after the same manner as the red colour which happens to Verdigreese calcined is a certain proof that it contains in it some particles of Cop∣per.

But that which is here said to pass for a thing un∣deniable, is no proof at all; for first of all those Vitriols which are thought most to partake of Cop∣per, do give no greater redness in their Calcina∣tion, than the others which partake the least of it. Secondly let Copper be prepared which way you please, you can never make it redder than the Col∣cothar of English Vitriol, whose redness must be thought to proceed from some particles of this metal contained in it. And thirdly, we see plain∣ly, that Iron, Lead, Mercury, and divers mineral bodies do acquire a red colour in their Calcining, without containing any Copper.

The Sympathetical powder that has made so much noise is nothing but white Vitriol opened, pre∣pared divers ways according to mens different con∣ceptions about it. The Roman Vitriol is better esteemed than the other for this operation.

The common method of preparing this Powder is to expose it to the heat of the Sun, whilst the Sun is in Leo, that is in July, in order to dry it, and to open it. And men think that Sign does be∣stow particular influences on the preparation. Though in truth it undergoes drying better in that season than another, by reason of the great heat

then of the Sun. And it may be the parts of the Vitriol do become more volatile by this heat, but for what is said of Influence it is meerly imagi∣nary.

Many do only pulverize the ordinary Vitriol, in order to make the Sympathetical powder.

When you would use this powder, you are to take the bloud of a wound upon a linnen cloth, and to sprinkle some of it upon the bloud. It is pretended, that though the bloudy linnen were ten miles off from the Patient, when the Sympatheti∣cal powder is applied to it, the wound would pre∣sently heal. But the experience of several per∣sons who have tried it (and others may do the same) does evince, that men have had a great faith, when they have talked of the effects of this powder; for if it be not applied to a cloth newly blouded, and even in the chamber of the Patient, you will certainly find no effect from it. Nay where such precautions have been used, it per∣forms no great matter, and sometimes does no∣thing at all.

Now to explicate the action of Vitriol, called Sympathy, you must know that there does con∣tinually exhale into the air, little bodies from this mineral salt, and to convince you of it, you need only to put the several Vitriols of different colours pretty near one another in the same place, you will find after 12 or 15 daies that they have all changed colour a little in their superficies. The white will become yellow, the green whitish, the blue greenish, the red grayish. These changes of colour cannot proceed but from little bodies, which being separated from each kind of Vitriol,

and mixing in the air, some part of them do fall confusedly on the matter. And it must not be said that these changes are caused by the air, which does open and rarefie these salts; for if you put them into places separate, or distant from one another, this effect will in no wise happen.

You must also observe that the bloud, to which the Vitriolick powder is applied, retaining some heat still, may thereby increase the activity and number of the little bodies which do arise from the Vitriol.

And these Vitriolick bodies dispersing them∣selves in the air are they that cause all the Sympa∣thy, for they do mix in the wound of the patient, and because the virtue of Vitriol is to stop the bloud, and to dry it, you need not wonder if the volatile parts which come from it, do perform the same effect.

But it may be objected, that the volatile parts of Vitriol have no more determination naturally to go find out the wound of a person, than other parts of the body, and other places of the chamber. Nay on the contrary, that a wound being common∣ly covered with a plaister, and somewhat thick ban∣dage, is not so likely to receive those bodies.

I answer, that there is no need of giving any other determination to these volatile parts of Vitriol, than is given to other volatile salts which are dispersed in the air; but because wounds are always of a glutinous temper, it is easie to conceive that these little bodies will ad∣here to them in greater quantity than to others, as any downy substance which flies about a room, wherein there is Glue, or Turpentine,

will more easily stick in them, than in other places.

As for the Bandage and Plaster, used to wounds, you must know that those who do use the Sympa∣thetical powder, do apply none of them. But when it happens, which is very rare, that a mans wound has been cured by this Powder, although there was a Plaister and bandage also laid upon it, this effect can never be attributed to any thing else but the penetration of Vitriol, for there are wounds that a very little quantity of Vitriol is ca∣pable of drying.

Thus I have given you the most rational expli∣cation that can be, of an effect which has hitherto passed for a thing altogether inexplicable.

To conclude, I would not advise any wounded person to insist or depend too much on a remedy of this nature; for to one who ever received consider∣able good, there's a hundred, who never perceived any effect from it, and the cause of it has been, that the volatile parts of the Vitriol have hapned to be diverted from the wound by some wind, or else because the greatest part of people have their bloud too subtile, and too active to be fixed by so little a quantity of Vitriol.

Nevertheless those whose heads are filled with the Sympathetical Powder do speak of it, as of a never failing medicine. And if a man offers to con∣vince them by an experiment to the contrary, as it is not hard to do, they presently cry out, that the reason it fails is, because it is ill prepared; but it is easie to convince them, if they desire a serious satisfaction in it, for the powder of their own pre∣paration, that they so much magnifie, though it be

successful in one, will be found to fail in a great many others.

Many Authors have also written a great many falshoods in defence of the Sympathy, as for ex∣ample, that if the urine of an Infant were cast into the fire so soon as it is made, it would cause a heat of urine: that if the excrements of an animal were thrown into the fire, or among Nettles, there would be an Inflammation in the guts of the same creature, and many the like stories, which a thousand experiments will prove not to be true.

Distillation of Vitriol.

This Spirit is an acid salt of Vitriol, dissolved into a liquor, by a great fire.

Fill two thirds of a large earthen Retort, or glass one luted, with Vitriol Calcined to white∣ness; place it in a close Reverberatory furnace, and fitting to it a great Balon or Receiver, give a very small fire to warm the Retort, and make the water come forth that might still remain in the Vitriol; and when there will distil no more, pour the water out of the Receiver into a Bottle, this is called Phlegm of Vitriol; it is used in Inflamma∣tions of the eyes to wash them with: refit the Re∣ceiver to the neck of the Retort, and luting the junctures exactly, encrease the fire by degrees, and when you perceive Clouds to come forth into the Receiver, continue it in the same condition, until the Receiver grows cold; then strengthen the fire with wood to an extream violence, until the flame rises through the Tunnel of the Reverberatory as

big as ones arm. The Receiver will fill again with white Clouds; continue the fire after this manner for three days, and so many nights, then put it out: unlute the junctures when the vessels are cold, and pour the Spirit into a glass body, set it in sand, and fit to it quickly a Head with its Receiver; lute the junctures close with a wet Bladder, and distil with a very gentle fire, about four ounces of it, this is the Sulphureous spirit of Vitriol, keep it in a viol well stopt.

It is good for the Asthma, Palsie, and diseases of the Lungs, the dose is from four drops to ten in some convenient liquor.

Change the Receiver, and augmenting the fire, distil about half the liquor that remains in the bo∣dy: this is called the Acid Spirit of Vitriol, it is mixed in Juleps to an agreeable acidity.

That which remains in the body is the most acid part of the Vitriol, and is improperly called Oil. It may be used like the acid Spirit, for continued Feavers, and other distempers that are accompanied with a violent heat. This Oil is likewise used for the dissolution of metals.

You'l find in the Retort a Colcothar which hath the same virtues with that I spoke of before.

Remarks.

To make the Spirit of Vitriol you must take green English Vitriol, such as being rubbed upon Iron doth not at all change colour, which shews it doth not partake of Copper, as the German does, that looks a little blueish, and is more acrimonious.

You must Calcine it as I have said, to the end it being deprived of the greatest part of its Phlegm, the distillation may be dispatched the sooner. A third part of the Retort is left empty, that the Spirits may have room to rarefie in, when they come forth.

There distils also a great deal of Phlegm into the Receiver, and all of it is known to have come, when there drops no more. Those who don't care for the sulphurcous spirit, do let it come forth, and mix together with the Phlegm, before the junctures are luted; but you must be sure to go∣vern the fire discreetly at that time; for these Spirits come with a great deal of violence, and use to break the Retort, when they are driven too furiously. When they are out, you must aug∣ment the fire to the last degree of all, for the acid Spirit will not part with its earth, until it is forced by an extraordinary heat.

If you distil eight pounds of white Vitriol, at sixteen ounces to the pound, you'l draw off se∣venteen ounces of Phlegm, and two and twenty ounces and a half, both of the Sulphureous, and the Acid spirit of Vitriol. Of these two and twenty ounces and a half, there will be five ounces of Sulphureous spirit.

You'l find in the Retort five pounds, five ounces of Colcothar.

Use all the care you can possible to preserve all the liquors which come from Vitriol, yet it will be impossible for you to hinder it from losing some through the junctures, during the distillation.

If you should use German instead of English Vi∣triol, you'd draw off a little more spirit than the

quantity I have named, but it would have some smell of Aqua fortis, and the matter which re∣mains in the Retort would be of a brown colour drawing towards black. This colour proceeds from sulphureous Fuliginosities which rise more from this Vitriol than the other, because it par∣takes of Copper; for this Sooty vapour finding no vent to get out at, falls down again upon the matter and blackens it.

The Furnace in which this operation is perform∣ed, must be very thick, that the heat of the fire being none of it lost through the Pores, may the bet∣ter act upon the Retort. These Spirits do rarefie into white vapours in the Receiver, which must be provided large enough, to give them free liberty to circulate in, before they condense into a liquor at bottom. The fire is usually continued four or five days together, but if after that, you should change the Receiver, and continue the fire three or four days longer, there would come forth an Oil of Vitriol congealed, and caustick, which is nothing but the more fixt part of the Sprit of Vi∣triol. And this Congelation hath given this liquor the name of Oil of Vitriol, though improperly.

Vitriol contains earth enough, wherefore none is added to it, as is necessarily done in the distilla∣tion of Niter.

Acid Spirits are Salts become fluid by the force of fire, which hath disingaged them from their more terrestrious part, and they may be revived again by pouring them upon some Alkali; for ex∣ample, the Spirit of Vitriol remaining some time upon Iron, doth reincorporate into Vitriol, and the Spirit of Niter, poured upon Salt of Tartar makes a Salt-peter.

There is one thing happens about the Oil of Vi∣triol, when it is very strong, which is strange indeed; it is, that if you mix it with its Acid Spi∣rit, or with water, or else with an Ethereal Oil, such as the Oil of Turpentine, this mixture grows hot to that degree, that sometimes it breaks the Viol it was put into, and often it produces a consider∣able Ebullition.

I could quickly give an account of this heat and Ebullition, if I would suppose an Alkali to be in the Oil of Vitriol, as those do who pretend to ex∣plicate every thing that happens by the notions of acid and alkali; but not comprehending how an alkali should be able to remain so long a time with so strong an acid as is the Oil of Vitriol without be∣ing destroyed, I had rather give a reason that seems to me abundantly more probable.

I conceive therefore that if water, or Spirit of Vitriol, or the Ethereal Oil of Turpentine do come to heat the Oil of Vitriol, it is by setting in mo∣tion a great many fiery particles which the Oil of Vitriol had drawn with it in the distillation; for these little fiery bodies being environ'd with salts that are exceeding heavy, and hard to rarefie, they drive about with vehemence whatsoever stands in their way, and when they have caused an Ebul∣lition, and find they can't get out at the top of the Viol, they break it to pieces with the bussle they make at bottom, and on the sides.

Perhaps it will be said, I do here suppose gra∣tis that the Oil of Vitriol does contain fiery parti∣cles; but if we consider the great violence of fire, and the time that is spent in drawing this acid, it will be no such hard matter to grant me this sup∣position.

Besides it will be hard to explicate the great and burning Corrosion of Oil of Vitriol without admitting these fiery parts, for the Vitriol contains nothing in it self of this Caustick nature; it is true indeed that it contains Phlegm, Sulphur, and Earth, but it is a thing impossible but this acid should discover it self more than it does, if it were as Corrosive in the Vitriol, as it is in the Oil.

Once it hapned to me, that putting into my Furnace a Retort whose two thirds were filled with German Vitriol dried, in order to draw off its Spi∣rits, I distilled first of all the Phlegm, and sulphure∣ous spirit, which I took out of the Receiver; I then fitted it again to the Retort, and by a great fire continued three days and three nights, I di∣stilled off the acid Spirit as we are used to do. When the vessels were cold, I admired to find in my Receiver nothing but a mass of Salt, or Congealed Oil of Vitriol. This Salt was so ex∣ceeding Caustick and burning, that if I offer'd to touch the smallest part of it with my finger, I pre∣sently felt an insufferable scalding, and was fain to put my hand immediately into water, it con∣tinued to fume still, and when a little of it was thrown into water, it made the same hissing noise, as a fire-coal flung into water would do. Besides it heated the water very much, and much more than common Oil of Vitriol could.

I kept this congealed Spirit about six months, after which time it dissolved into a liquor, which I used as Oil of Vitriol; for it was in effect the same thing.

And in my opinion this operation does sufficient∣ly evince, that Oil of Vitriol contains fiery parts.

It hapned to me another time, that having recti∣fied the Spirit of Vitriol, to separate it from its Oil by an Alembick, some part of the distilled Spirit was turned into fair and transparent Cry∣stals in the bolt-head, or Receiver, which Cry∣stals had the same acrimony, and strength with the mass I now spoke of.

If you pour some drops of Spirit, or Oil of Vi∣triol into a quart of hot water, in which you shall infuse a pugil of dried red Roses, the liquor will in a little time become as red as Claret; and this effect must not so much be attributed to the Spirit of Vitriol's sharpning the water, and so thereby drawing out the Tincture of Roses, as to this that the acid Spirit does rarefie and separate the parti∣cles of the Rose (which the water had dissolved) and made to appear better than before; for if you strain the Infusion, and separate the Roses, before you pour to it your Spirit of Vitriol, although the liquor so strained be yet but little raised in colour, it will nevertheless turn to as high a red, after the Spirit is dropt into it, as if the Roses remain∣ed still in the liquor. We must say the same thing of other Tinctures that are drawn by acids, as al∣so of such as are made by an Alkali salt.

If you fill a glass Viol with the decoction of Nephritick wood clarified, and look on it, turning toward the light, it will appear yellow; but if you turn your back to the light, it will appear blue; if you mix with it some drops of Spirit of Vitriol, it will appear yellow on every side, but if you again add about as much more Oil of Tartar, it will return unto its first colour.

If you take a Blue, or Violet tincture made in water, such as is drawn out of the Sun-flower, or Violet flowers, and pour upon it some drops of Spirit of Vitriol, it will presently turn red; but if you throw into it some Alkali salt, it will recover again its former colour.

On the contrary if you pour an Alkali liquor, such as volatile Spirit of Sal Armoniack, or the Oil of Tartar, upon the blue Tincture, it will pre∣sently turn green; and if you again pour upon it a little Spirit of Vitriol, it will change this colour in∣to an obscure red.

The decoction of Indian wood is very red: if you drop into it a little Spirit of Vitriol it will turn yellow; and if you still add some volatile Spirit of Sal Armoniack it will become black.

If you infuse three or four hours a piece of Indi∣an wood in some clear juice of Citron, and take out your wood, the liquor will have received no alteration of colour, but if you add to it some drops of Oil of Tartar made per deliquium, it will take a brown colour, and if you add to it a little Spirit of Vitriol, it will resume its colour again.

If you pour some drops of Oil of Tartar upon Claret, it will become greenish, and if you add to it a little Spirit of Vitriol, it will return to its former colour.

All these changes of colour, which the Spirit of Vitriol, or other acids, and Alkali's do make, proceed only from the different position of bodies dissolved in the liquor, and from its disposition to modifie the light different ways.

Styptick Water.

This water is a solution of Vitriol and other ingredients, to stop bleedings.

Take Colcothar, or the red Vitriol that remains in the Retort after the spirit is drawn out, Burnt∣alom, and Sugar-candy, of each half a drachm, the Urine of a young person, and Rose-water, of each half an ounce, Plantain-water two ounces, stir them all together a good while in a mortar, then pour the mixture into a Viol, and when you use it, separate it by Inclination.

If you apply a Bolster dipt in this water to an opened Artery, and hold your hand a while upon it, it stops the bloud. In like manner you may wet a little Pledget in it, and thrust it into the Nose, when an Hemorrhage continues too long; taken inwardly, it cures spitting of bloud, bloudy flux, and the immoderate flux of the Hemorrhoids, or Terms, the dose is from half a drachm to two drachms in Knot-grass water.

Remarks.

When the bloud gushes forth too fast, you must redouble the first Bolster, that was put upon the wound, and assist it a little with your fingers for half an hour.

The Basis of this water is Colcothar.

Having used this water with good success upon several occasions, I was willing to insert it in this

Book, and I believe if any body please to experi∣ment it, as I have done, they will easily acknow∣ledge it to be an excellent Remedy in many Di∣stempers.

Lapis Medicamentosus.

Powder and mix together Colcothar, or the red Vitriol, that remains in the Retort after distilla∣tion, or in want of it Vitriol Calcined to a red∣ness two ounces, Litharge, Alom, and Bole-Ar∣menick, of each four ounces; put this mixture into a glazed pot, and pour upon it good Vinegar enough to cover the matter two fingers high; cover the pot and leave it two days in digestion, then add to it eight ounces of Niter, two ounces of Sal Armoniack; set the pot over the fire, and evaporate all the moisture, Calcine the mass that remains, about half an hour in a strong fire, and keep it for use. It is a good Remedy to stop Go∣norrheas, a drachm of it is dissolved in eight ounces of Plantain water, or Smith's water, to make an Injection into the Yard; it is likewise good to cleanse the eyes in the small pox, seven or eight grains of it must be dissolved in four ounces of Plantain or eye-bright water; it is also good to stop bloud, applied outwardly to a wound. It may be dissolved in Knot-grass water, and will go near to have the same effects as the styptick water.

Remarks.

This stone is called Medicamentosus by way of excellence, by reason of the good effects it pro∣duces.

The Colcothar, that remains in the Retort after the distillation of Vitriol, must be better than the others for this Operation; because being de∣prived of the greatest part of its Spirits, it is the more Astringent.

Litharge, which is a Lead Calcined, Alom, and Bole-Armenick, are so many considerable Astrin∣gents, that do no hurt in this composition.

Vinegar is put in to incorporate the ingredients together, and set them a Fermenting, after which the Niter and Sal Armoniack do easily mix among the rest.

The Calcination which is given to it at the end, is done to carry off some part of the acid, and to augment the Astriction: It likewise fixes the stone the more, and makes it fitter to keep.

It is one of the best Remedies I ever met with, for stopping Gonorrheas, when it is a proper time to stop them by Injections.

Salt of Vitriol.

This Operation is the more fixed Salt of Vitriol, that remains after distillation.

Take two or three pounds of the Colcothar, that remains in the Retort after distillation of Vitriol,

let it infuse in eight or ten pints of warm water for ten or twelve hours; boil it a little while, and then let it settle; separate the water by Inclina∣tion, and pour new water upon the matter; pro∣ceed as before, and mixing your Impregnations, evaporate all the moisture in a sand-heat in a glass or earthen vessel, there will remain a salt at bot∣tom.

It is used as the Gilla Vitrioli, to give a Vomit; the dose is from ten to thirty grains.

Remarks.

This salt is that part of the Vitriol that the fire is not able to rarefie into Spirit. Some Authors say, that it Vomits just after the same manner, as Gilla Vitrioli, taken in a smaller dose, but I have observed that its effect was much less, and on the contrary there was need of giving it in a larger dose than the Gilla, to procure a Vomit; for having given of it several times a drachm at a dose, the person had no Inclination at all to Vo∣mit; and truly I am apt to believe that a fixt salt of Vitriol divested of its Sulphur, doth rather tend to precipitate downwards than mount up∣wards; for Vomiting is caused by Saline Sulphurs, which prick the Fibers of the Stomach, whence follows a Convulsion to this part.

That which remains indissoluble is called Caput Mortuum, it is used for Astringents.

If you expose it to the Air for a year, or a year and half, it returns into Vitriol again.