Chapter XLVIII: Section III: Of Operations on the SEMI-METALS (1)

CHAP. I.

_Of_ ANTIMONY.

PROCESS I.

_To Separate Antimony from its Ore by Fusion._

Having drilled some small holes, of about two lines in diameter, in the bottom of a crucible, put into it your Antimonial Ore broken into little bits, about the size of a hazel nut; lute on its cover; set the crucible thus prepared in the mouth of another crucible, and close the joints with lute.

At the distance of half a foot from this compound vessel place bricks all round, so as to form a furnace; the sides of which must rise as high as the brim of the uppermost crucible.

Let the bottom of this furnace be filled with ashes, up to the top of the lower crucible, and the rest of the furnace with lighted coals. Blow the fire, if it be necessary, with bellows, till the upper crucible become red. Keep it up in this degree for about a quarter of an hour. Then take your vessels out of the furnace, and you will find the Antimony collected in the bottom of the lower crucible, having run through the holes of the upper one.

_OBSERVATIONS._

The ore of Antimony is one of the most fusible: it always contains a great deal of Sulphur, and cannot sustain a fire of any force without being dissipated into vapours. It requires no additament to flux it: for it is not necessary, on this occasion, that the earthy and stony matters mixed therewith be brought to fusion. It is sufficient that the Antimonial part be melted; which, as soon as it becomes fluid, is carried by its weight to the lower part of the crucible. Thus it is separated from all heterogeneous matters; which are left in the upper crucible, while it passes through the holes in its bottom, and forms a mass in the lower.

The precaution of closing all the apertures of both crucibles is necessary, on account of the volatility of this mineral: and that the Antimony, when once melted, may not continue exposed to a great heat, it is made to run down into a vessel surrounded with ashes only, and by that means very little affected with heat; ashes being one of those solid mediums that transmit least of it.

PROCESS II.

_The common Regulus of Antimony._

Reduce crude Antimony to powder. Mix it with three fourths of its weight of white Tartar, and half its weight of refined Salt-petre, both pulverized. Into a large crucible made red-hot in the fire, throw a spoonful of your mixture, and cover it. There will be a very considerable detonation. When it is over, throw in a second spoonful of your mixture, and cover the crucible as before: this will produce a second detonation. Go on thus, till you have thrown in all your mixture.

When the whole has thus fulminated, increase the fire so as to bring the matter into fusion; that being done, take the crucible out of the furnace, and immediately pour its contents into an iron cone heated and greased with tallow. Strike the floor and the cone some gentle blows with a hammer, to make the Regulus precipitate: and when the matter is fixed and cold, invert the cone and turn it out. You will see it consist of two distinct substances; the uppermost of which is a saline scoria, and the undermost the reguline part. Strike this mass a blow with a hammer, in the place where these substances join, and you will by this means separate the scoria from the Regulus; the latter of which will have the form of a metallic cone, on whose base you will observe the signature of a bright star.

_OBSERVATIONS._

Antimony, though separated by a former fusion from the earthy and stony parts of its ore, must nevertheless be still considered as an ore, on account of the great quantity of Sulphur it contains, which mineralizes the metalline part or Regulus. Therefore, if you desire to have this Regulus pure, you must separate it from the Sulphur that is combined with it. This may be done several ways. The method above proposed is one of the readiest and easiest, though not altogether free from inconveniencies, as we shall shew.

The Salt-petre in the mixture detonates by means of the Sulphur of the Antimony, which it consumes, and from which it separates the reguline part: but lest it should also consume some of the phlogiston which gives the Regulus its metalline form, Tartar is added; because it contains a great deal of inflammable matter, and so is capable of furnishing enough for the detonation of the Nitre, or rather for restoring to the metallic earth of the Antimony, the phlogiston that may be consumed by the Nitre.

If we consider what passes in this operation we shall soon be convinced that a great deal must be lost in it, and that we do not thereby obtain near the whole of the Regulus that the Antimony is capable of yielding: for, 1. the Regulus of Antimony being a volatile substance, much of it must be dissipated during the detonation; and so much the more as the detonation is frequently repeated, and continued for a considerable time. The flowers that may be collected by presenting cold bodies to the smoke that rises in the operation, and which may be reduced to a Regulus by the addition of a phlogiston, sufficiently prove what is here advanced.

2. All the Sulphur of the Antimony is not consumed by the Nitre on this occasion; and moreover, the Acid of that part thereof which is burnt, uniting with some of the Alkali produced by the deflagration of the Nitre and Tartar, forms a Vitriolated Tartar, which meeting with a sufficient quantity of phlogiston in the mixture produces new Sulphur. Now this Sulphur, whether not consumed, or reproduced, in the operation, combining with the Alkali forms a Liver of Sulphur; and that dissolves part of the Regulus, which by this means remains confounded with the scoria. The proof of this is, that, if the scoria be mixed with filings of iron, and fused a second time, you will find at the bottom of the crucible a button of Regulus, which it contained, and which is separated therefrom by the interposition of the Iron. We shall say more on this subject in the process for making the Martial Regulus, which immediately follows this. If, instead of melting the scoria with iron filings, we pulverize it, boil it in water, and then pour an acid into that water; the liquor will instantly grow turbid, and a Sulphureous Precipitate will fall, commonly called _the Golden Sulphur of Antimony_; which is nothing else but common Sulphur still combined with some particles of the Regulus; a new proof of what we advanced concerning the production of Liver of Sulphur in this operation.

As Regulus of Antimony is of no great value, the loss sustained in this process is seldom regarded. However, we shall have occasion, in the sequel, to point out a method of obtaining this Regulus with less disadvantage.

PROCESS III.

_Regulus of Antimony precipitated by Metals._

Put one part of small iron nails into a crucible, and set it amidst burning coals, in a melting furnace. When the iron is thoroughly red-hot, and begins to grow white, add thereto little by little, and at several times, two parts of crude Antimony in powder. The Antimony will immediately flow and unite with the Iron. When the Antimony is entirely melted, add thereto, at several times, the fourth of its weight of pulverized Nitre: a detonation will ensue, and the whole mixture will be in fusion.

After you have kept the matter in this condition for some minutes, pour it into an iron cone, first heated and tallowed. Strike the sides of the cone with a hammer, that the Regulus may fall to the bottom; and, when all is cold, separate it from the scoria by a blow with a hammer. Melt this first Regulus again in another crucible, adding a fourth part of its weight of crude Antimony. Keep the crucible close shut, and give no more heat than is necessary to melt the matter. When it is in perfect fusion, add to it at several times, as you did before, the sixth part of its weight of pulverized Nitre; and, in half a quarter of an hour after this, pour the whole into a cone as you did the first time.

Lastly, melt your Regulus over again a third, or even a fourth time, always adding a little Nitre, which will detonate as before. If after all these fusions you pour the Regulus into an iron cone, you will find it very beautiful, and the star well formed: it will be covered with a semi-transparent, lemon-coloured scoria. This scoria is extremely acrid and caustic.

_OBSERVATIONS._

Though Regulus of Antimony unites very readily with Sulphur, and is always found combined therewith in the earth, we must not thence conclude that it hath a greater affinity than other substances with that mineral: on the contrary, all the metals, except Gold, have a greater affinity than this Semi-metal with Sulphur. Hence it follows that all the metals, except Gold, are capable of decomposing Antimony, and separating the sulphureous part from the metalline; so that, instead of employing Iron, as in our process, Copper, Lead, Tin, or Silver, may be used, and a Regulus obtained by means thereof.

But as Iron is, of all the metallic substances, that which hath the greatest affinity with Sulphur, it is on this occasion preferred to the rest. And from hence two advantages arise: the first is, that the operation is performed sooner and with greater ease: the second, that the Regulus is purer, and contains less of the precipitating metal. For it is a general rule, that, when one metallic substance is employed to precipitate another, the precipitated substance is always a little adulterated by the admixture of some particles of the precipitant. Now, the greater affinity the precipitant hath with the matter united to that which is to be precipitated, the less doth the precipitate retain of the precipitant.

In this process the Iron melts very easily by means of the union it contracts with the Sulphur; which, as we observed before, hath the property of rendering this metal very fusible, though of itself the most refractory of all.

The scoria found on the Regulus of the first fusion is a combination of Iron with the sulphureous part of the Antimony. This scoria is extremely hard, and not to be separated from the Regulus without some trouble. The Nitre added, being alkalizated and united therewith, renders it a little softer, and gives it the property of relenting in the air. Any Alkaline Salt may be substituted for the Nitre.

The Nitre that is alkalizated in the operation, or the Alkali that is added, procures moreover another advantage; namely, that, by uniting with part of the Sulphur of the Antimony, it produces a Liver of Sulphur, which dissolves the Iron, retains it, and hinders that which is not yet combined with pure Sulphur from uniting so readily with the Regulus as it otherwise would do.

Lastly, the addition of Nitre, or an Alkali, contributes greatly to promote the fusion, to render it more perfect, and to procure a more complete precipitation of the Regulus.

The second fusion which the Regulus is made to undergo is intended to purify it from any mixture of Iron. When the fresh Antimony added on that occasion comes to melt with the Regulus, the Sulphur contained in the Antimony joins with the ferruginous parts in the Regulus; and the Iron becoming lighter by this union is thrown up to the surface of the matter. There it forms a sort of scoria, with which a good deal of Antimony is mixed; the Regulus not being wholly precipitated, because there is not Iron enough in the mixture for that purpose. The Salt-petre added here produces the same effect as in the first fusion.

But if, on one hand, the Regulus precipitated in the first fusion be purified, by this addition of fresh Antimony, from most of the Iron with which it was alloyed; on the other hand, this same Regulus cannot be kept from re-uniting with some sulphureous parts.

In order therefore to separate it entirely from these, it must be melted over again once or twice more, and a little Nitre added each time, to consume them by deflagration. But this cannot be done without consuming also some of the very phlogiston which gives the Regulus its metalline form: whence it comes to pass that part of the Regulus is converted to a calx, which, by means of the alkalizated Nitre, is turned into glass; and it is this glass which mixing with the scoria gives it the yellow colour observed therein. This yellow colour may also be in part produced by some ferruginous particles, of which a small quantity always remains combined with the Regulus, notwithstanding its former depuration by Antimony.

It is of no use to repeat the fusions of the Regulus oftener than is above proposed, or to add fresh Nitre with a view to consume the Sulphur it may still contain: for after the second fusion it contains none at all, and retains only the phlogiston necessary to give it the metalline form. So that, by prosecuting the matter further, you would only calcine and destroy the Regulus to no manner of purpose.

From what hath been said it is plain that, even by this process, we do not obtain all the Regulus which our Antimony is capable of yielding; seeing part of it is destroyed by the fusions it must necessarily undergo with Nitre, in order to its purification. We shall give a process for obtaining from Antimony the greatest quantity of Regulus it can possibly be made to yield, after we have treated of its Calcination, which is in some sort the first step of that process.

PROCESS IV.

_The Calcination of Antimony._

Take an unglazed earthen vessel, wider at top than at bottom; put into it two or three ounces of crude Antimony finely pulverized. Set this vessel over a weak charcoal fire, and increase the heat till you see the Antimony begin to smoke a little. Continue the fire in this degree, and keep incessantly stirring the Antimony with the shank of a tobacco-pipe all the while it is upon the fire.

The powder of Antimony, which, before calcination, was of a brilliant colour inclining to black, will become dull, and look like an earth. When it comes to have this appearance raise your fire till the vessel be red-hot, and keep it up in this degree till the matter cease entirely to smoke.

_OBSERVATIONS._

Antimony, as hath been already said, is a sort of ore consisting of a metalline or reguline part mineralized by Sulphur.

The design of this calcination is, by the action of fire, to dissipate the sulphureous part, which is the most volatile, in order to separate it from the metalline part. It is evidently a real torrefaction; but the operation is very difficult, and requires a good deal of attention; for Antimony very easily melts, while at the same time it is necessary to our success that it do not melt; because when the matter is in fusion the Sulphur requires a much greater degree of heat to carry it off. Now, as Regulus of Antimony itself is very volatile, a good deal of it would be dissipated along with the Sulphur, if it were exposed to the degree of heat necessary to carry off the Sulphur when the mass is melted.

Therefore if it happen that the Antimony begin to melt during the calcination, which is easily perceived by its running into clots, it must be taken off the fire, and the clotted parts be again pulverized; after which the calcination is to be prosecuted with a less degree of heat.

When the Antimony has lost all its brightness, and is become like an earth, it is time to augment the degree of heat, in order to complete the calcination; because the last portions of the Sulphur are the most difficult to raise. Moreover, the inconveniences just mentioned are not now to be apprehended: for, as the great fusibility of the reguline part is owing to the Sulphur, what remains, after you have dissipated the greatest part of the Sulphur, is much less fusible; and, as the redundant Sulphur of the Antimony cannot be driven off, without dissipating at the same time a good deal of the phlogiston necessary to metallize its Regulus, the matter that remains comes much nearer to the nature of a calx, than to that of a metalline substance; and consequently partakes of the nature of all metallic calces, which is to be very fixed.

Antimony may also be calcined by mixing with that mineral an equal quantity of charcoal-dust. As charcoal is incapable of fusion, it prevents the Antimony from clotting, as well as from losing so much of its metallizing phlogiston as it otherwise would: and hence it comes to pass that the calx of Antimony, prepared in this manner, comes nearer to the nature of a Regulus, than that which is prepared without addition.

If you happen to raise the fire too much, in this calcination with charcoal-dust, the calx will be partly reduced to a Regulus, by means of the phlogiston which the charcoal furnishes; and then the Regulus will be dissipated in vapours, especially as this calx, which comes very near the nature of a Regulus, is not so fixed as that prepared without addition. For this reason it always continues to smoke, even when it contains no superfluous Sulphur: and therefore you must not wait till it cease to smoke before you put an end to your calcination; for you will lose a great deal of it in vapours. It is time to stop when the vapours that rise from it, while it is moderately red, do not smell of burning Sulphur.

PROCESS V.

_Calx of Antimony reduced to a Regulus._

Mix the calx of Antimony, which you intend to reduce, with an equal quantity of black soap. This mixture will make a thin paste. Put it little by little into a crucible, previously made red-hot amidst live coals. Thus let the soap burn till it cease to emit any oily smoke. Then cover the crucible; make the fire strong enough to melt the matter, and you will hear it effervesce and boil. When this noise is over let the crucible cool, and then break it: you will find in it a beautiful scoria, marked with circles of several colours; and under that a button of Regulus, which is not yet quite pure, and must be purified in the following manner.

Pound this Regulus, and mix it with half its weight of an antimonial calx as perfectly desulphurated as possible. Put it into a crucible, and cover it: melt the whole, so that the surface of the melted matter may be smooth and uniform. Let the crucible cool, and then break it: you will find in it a beautiful button of very pure Regulus, covered with a scoria having the appearance of an opaque glass, or a kind of greyish enamel, moulded on the finely radiated surface of the Regulus.

_OBSERVATIONS._

Of all the metalline calces that of Antimony is most easily reduced. Any matter that contains the phlogiston, even charcoal-dust alone, is sufficient to procure it the form of a Regulus, without the addition of any thing to facilitate its fusion; because this calx, which is not of itself altogether refractory, becomes still more fusible as it combines with the phlogiston, and approaches to the reguline state.

Though all inflammable matters are capable of procuring the reduction of the calx of Antimony, yet there are some with which the operation succeeds better, and produces a greater quantity of Regulus, than it does with others. Fatty matters, joined with Alkalis, are those which answer best in this reduction, as they do in most others. The black flux, for instance, is very proper for this purpose: but Mr. Geoffroy, who made many experiments on Antimony, found by repeated trials that black soap is still fitter for it, and that a greater quantity of Regulus was obtained by its means, than by any other reducing flux whatever. The process here given is taken from one of the Memoirs on this subject, which he laid before the Academy of Sciences.

Black soap is made of the lye of a Fixed Alkali, such as potash for instance, with quick-lime, incorporated by boiling with oil of lint-seed, rape-seed, or hemp-seed, and sometimes also with animal fat. The oily matters, contained in this reducing flux, are first burnt and charred to a coal in the crucible. As soon as they are brought to this state, the crucible is covered, and the fire is increased, till the matters melt. At that instant the reduction begins to take place; and the bubbling noise observed is an effect thereof.

The Regulus obtained by this first fusion is not yet very pure, being adulterated with the mixture of some unmetallic earth that was contained in the Antimony, and with a portion of the calcarious earth of the soap.

Mr. Geoffroy found that his Regulus was contaminated with this substance, by putting it into water: for on that occasion he observed a very brisk ebullition about the reguline buttons, which sometimes lasted above four and twenty hours; and on examining them with a glass, he discovered some little holes, imperceptible to the naked eye, through which the water entered, to unite with the lime retained in the internal parts of the Regulus, which having been recalcined in the operation required to be slaked.

This Regulus may be purified by simple fusion, without any additament, because the particles of lime, being lighter than those of the Regulus, will be thrown up to the surface, on which they will form a sort of scoria. But Mr. Geoffroy took notice that, in this case, the surface of the Regulus is never very neat; that it is always sullied with a very adhesive scoria, and that no star is formed upon it. Besides, the Regulus must be kept a long while in very thin fusion, that the heterogeneous matters, which hinder the perfect re-union of its parts, may have time to rise to the surface by their lightness. But the longer the Regulus is kept in fusion, the more of it evaporates, because of its volatility. He was therefore obliged to have recourse to other means.

We have in the process described the method which succeeded best with Mr. Geoffroy. It consists in melting the Regulus over again, with the addition of a little fresh calx of Antimony thoroughly freed from its Sulphur. This calx being in its nature easily vitrifiable, and combining with the earthy parts that deprave the Regulus, and which cannot be vitrified without addition, scorifies these matters, and with them forms the opaque glass, or kind of enamel which is found over the Regulus purified in this manner.

The star on that part of the Regulus of Antimony, which was contiguous to the scoria, is a mark of its purity, and a proof that the operation was well performed. This star is nothing but a particular disposition of the parts of the Antimony, which have the property of running naturally into facets and needles. The perfect fusion, both of the Regulus and the scoria that covers it, leaves the parts of the Regulus at liberty to range themselves in this order. This disposition appears not only on the upper surface of the Regulus, but, if you break the button, you find the same in its internal parts. There are some round pyrites whose insides have nearly the same appearance, and seem to consist of rays issuing from a common center.

The quantity of Regulus obtained by Mr. Geoffroy's process is more than double of what is procured in the common way, which yields but about four ounces in the pound; whereas this gives from eight to ten ounces.

When Antimony is calcined with charcoal-dust, what remains after the dissipation of all the Sulphur is not, properly speaking, a calx of Antimony; but a sort of Regulus quite formed, and differing from the common Regulus only in that its parts are disunited, and not collected into a mass. For if this pretended calx of Antimony be melted, it directly coalesces into a Regulus, without the addition of any inflammable matter fit to procure its reduction. Indeed less Regulus is obtained by this means than when a reductive is added: but nevertheless this experiment still proves what I advanced; seeing Regulus of Antimony cannot be melted without losing more or less thereof, either because some of it is dissipated in vapours, or because part of it loses its phlogiston in the fusion, and so is converted into a calx.

PROCESS VI.

_Antimony calcined with Nitre. Liver of Antimony. Crocus Metallorum._

Pulverize and mix perfectly together equal parts of Nitre and Antimony: put the mixture into an iron mortar, and cover it with a tile, which however must not shut it quite close. With a live coal set fire to the matter in the mortar, and immediately withdraw it. The mixture will flame, with great detonation; which being over, and the mortar cooled, invert it, and strike its bottom to make all the matter fall out. Then, by a blow with a hammer, separate the scoria from the shining part, which is the _Liver of Antimony_.

_OBSERVATIONS._

In this operation the Nitre takes fire and detonates with the Sulphur of the Antimony; and nothing remains but the metallic earth of the mineral, which, meeting with no substance to restore its phlogiston, cannot take the form of a Regulus; but, being combined with a large quantity of fused saline matters, begins itself to flow, and forms a sort of vitrification; which, however, is not a complete one, because the matters do not continue long enough in fusion, but cool too soon. This preparation of Antimony is a violent Emetic. It is used to make Emetic Wine and Tartar Emetic: it is also given in substance to horses.

The saline matters found after the operation in the form of a scoria, or perhaps confounded with the Liver of Antimony, are combinations of Fixed Nitre, partly with the Acid of the burnt Sulphur, forming a Neutral Salt of the same kind as Vitriolated Tartar, and partly with some unburnt Sulphur, forming a sort of Liver of Sulphur that contains a little Regulus. It is usual to pulverize this Liver of Antimony and wash it with water, in order to dissolve and carry off all the Salts. When thus pulverized and washed it is called _Crocus Metallorum_. If Liver of Antimony be melted with any inflammable matter, it will be reduced to a Regulus; because it is nothing but a metalline calx half vitrified.

PROCESS VII.

_Another Calcination of Antimony with Nitre. Diaphoretic Antimony._ Materia Perlata. Clyssus _of Antimony_.

Mix one part of Antimony with three parts of Nitre; project this mixture by spoonfuls into a crucible kept red-hot in a furnace. Each projection will be attended with a detonation. Continue doing this till you have used all your mixture: then raise the fire, and keep it up for two hours; after which throw your matter into a pan full of hot water. Let it lie steeping in water kept hot for a whole day. Then pour off the liquor: wash the white powder you find at bottom in warm water; and repeat the ablutions till the powder become insipid. Dry it, and you have _Diaphoretic Antimony_.

_OBSERVATIONS._

This operation differs from the preceding one, in respect of the quantity of Nitre deflagrated with the Antimony. In the former we added one part only of Nitre to one part of Antimony; but in this three parts of Nitre are put to one of the mineral; and the calx resulting from this mixture is of course very different from the other.

In the first place, Liver of Antimony hath a reddish colour; whereas Diaphoretic Antimony is very white. Secondly, Liver of Antimony is in a manner half vitrified; Diaphoretic Antimony is, on the contrary, in the form of a powder, the parts of which have no connection together.

The reason of these differences will easily appear, if we consider, that, Liver of Antimony being the result of calcination with one part of the Nitre only, which is not sufficient to consume all the Sulphur of the mineral, what remains after the detonation is not entirely deprived of its phlogiston; from whence arise the colour it retains and the ease with which it flows in the fire: but that, when three parts of Nitre are added instead of one, this quantity is not only sufficient to consume all the Sulphur and the phlogiston of the Antimony, but even more than enough; seeing that, after the operation, some Nitre is still found undecomposed.

The calx of Antimony, prepared by calcining it with three parts of Nitre, is therefore deprived of all its phlogiston. This is the cause of its whiteness, and the reason why it is not half vitrified by the operation, as Liver of Antimony is: for we know that the more a metallic calx is deprived of its phlogiston, the less fusible and the less vitrifiable it is. This calx of Antimony bears the name of _Diaphoretic Antimony_, or _Diaphoretic Mineral_: because, being neither emetic nor purgative, it is thought to have the virtue of promoting perspiration.

Antimony may be calcined with various proportions of Nitre, between that used to make Liver of Antimony, and this with which Diaphoretic Antimony is prepared; and from these calcinations will result calces possessed of properties both chymical and medical, of an intermediate nature between the extremes of those two preparations. The nearer the proportion of Nitre comes to that employed in preparing Liver of Antimony, the more will the resulting calx resemble that preparation; and in the same manner, a calx prepared with a greater proportion of Nitre will so much the more resemble Diaphoretic Antimony, as the proportion of Nitre used comes nearer three parts of Nitre for one of Antimony.

It is not necessary that Antimony in substance be employed to make the Diaphoretic Mineral: you may, if you please, make use of its Regulus. But as the Regulus contains no Sulphur, nor any more phlogiston than is requisite to secure its metalline form, it is needless to put three parts of Nitre to one of Regulus; an equal quantity thereof being sufficient.

The matter is projected by spoonfuls, to the end that, by gradual and repeated detonations, the Antimony may be more perfectly calcined: it is also with a view to destroy entirely the small remainder of phlogiston, which may have escaped the action of the Nitre, that the matter is kept red-hot in the crucible for two hours.

The whole is afterwards thrown into hot water, and left steeping therein for several hours, with design to give the water time to dissolve all the saline matters that are mixed with the Diaphoretic Calx. When crude Antimony is used in making this preparation, these saline matters are, 1. an Alkalizated Nitre; 2. a Neutral Salt formed by the union of the Acid of Sulphur with part of that Alkali, as in the preparation of Liver of Antimony; 3. a portion of undecomposed Nitre.

The water in which the Diaphoretic is washed takes up moreover a portion of the calx of Antimony, which is exceeding finely attenuated, and continues united with the fixed Nitre, and suspended therewith in the liquor. This matter is to be separated from the Fixed Nitre, by mixing the water wherein it is dissolved with an Acid, which unites with the Alkali, and precipitates this matter in the form of a white powder, to which the name of _Materia Perlata_ hath been given. Because it is precipitated in the same manner as the Golden Sulphur of Antimony, and, like that, is found in the water with which the saline matters are washed out, after the detonation of Nitre with Antimony, some Chymists have given it, though very improperly, the name of the _Fixed Sulphur of Antimony_.

This matter is a true Calx of Antimony, and differs from Diaphoretic Antimony in nothing but its being still more perfectly calcined. It is so indeed to such a degree that it is impossible to restore its metalline form, or reduce it to a Regulus, by the addition of an inflammable matter. Diaphoretic Antimony, on the contrary, may be re-metallized, by supplying it with phlogiston: but it must be observed that, in whatever manner you go about this, you will obtain a much smaller quantity of Regulus, than when you use a Calx of Antimony prepared with a smaller quantity of Nitre.

If you attempt to reduce either Liver of Antimony or Diaphoretic Antimony, great care must be taken to wash them thoroughly, in order to free them from every thing saline: for, without this precaution, the Acid of the Sulphur, having, as was observed, formed a Neutral Salt with the Alkali of the Nitre, will combine with the inflammable matter added to revivify the calx of Antimony and reproduce a Sulphur; which, uniting afterwards with the same Alkali, will produce a Liver of Sulphur, that will dissolve part of the Regulus, hinder its precipitation, and greatly lessen the quantity which might otherwise be expected.

A particular sort of Diaphoretic Antimony is sometimes prepared for Medical uses, which hath a purgative quality: it is not washed at all, and is therefore called _Unwashed Diaphoretic Mineral_.

Diaphoretic Antimony may also be prepared in close vessels, by means of which the vapours that rise during the operation are retained. For this purpose a tubulated retort is employed, having a series of adopters fitted to it. The retort is placed in a furnace, and heated till its bottom become red: then a very small quantity of the mixture, for making Diaphoretic Antimony, is introduced through the tube in the upper part of the retort, and the tube immediately stopped. A detonation ensues, and the vapours expand themselves into the adopters, where they condense. This is repeated till the intended quantity of matter be used. After the operation some white flowers are found sublimed in the neck of the retort, and a small quantity of liquor in the recipients. This liquor is acid. It consists of some of the Acid of the Nitre, which the Acid of the Sulphur hath expelled from its basis, and also a little of the Acid of the Sulphur carried up by the heat before it could combine with the basis of the Nitre. This liquor is called _Clyssus of Antimony_. The name of _Clyssus_ is given to all liquors in general that are prepared by this method.

The white flowers found in the neck of the retort are flowers of Antimony; that is, a calx of Antimony forced up by the heat, and by the impetus of the detonation. These flowers may be reduced to a Regulus. What remains in the retort is the same with the matter that remains in the crucible, wherein the mixture of Nitre and Antimony for making Diaphoretic Antimony hath been deflagrated.

Neither Diaphoretic Antimony nor the Pearly matter are soluble in any Acid.

PROCESS VIII.

_Calx of Antimony Vitrified._

Take any quantity you please of calx of Antimony, made without addition; put it into a good crucible, which set in a melting furnace: kindle the fire gradually, and leave the crucible uncovered at the beginning.

A quarter of an hour after the matter is red-hot, cover the crucible, and excite the fire vigorously till the calx melt. You may know when it is thoroughly melted, by dipping into the crucible an iron wire, to the end of which a little knob of glass will adhere, if the matter be in perfect fusion. Keep it in fusion for a quarter of an hour, or rather longer if your crucible can bear it. Then take it out of the furnace, and immediately pour out the melted matter on a smooth stone, made very hot for the purpose: it will presently fix into a yellow Glass.

_OBSERVATIONS._

All the calces of Antimony, when exposed to a violent fire, are converted into Glass; but not all with the same facility. In general, the more of their phlogiston they have lost in the calcination, the more difficult is their vitrification. This causes also a difference in the colour of the Glass; which will be of so much a deeper yellow, and the nearer to a red, the less the Antimony was calcined.

It frequently happens, when we employ a calx of Antimony which is not sufficiently deprived of its phlogiston, that we find in the crucible a button of Regulus, which, being heavier than the Glass, always lies at the bottom. With a view to avoid this inconvenience, and to dissipate completely the excess of phlogiston that may still be left in the calx of Antimony, we direct the crucible to be left uncovered for some time, at the beginning of the operation. If, notwithstanding this precaution, any Regulus be still found at the bottom of the crucible, and you resolve to vitrify it, the crucible must be returned to the furnace, and the fusion continued; by which means the Regulus will at last be converted into Glass.

If, on the contrary, you meet with any difficulty in effecting the vitrification, on account of your having employed a calx that hath lost too much of its phlogiston, such as Diaphoretic Antimony, or the Pearly matter, the fusion may be greatly facilitated by throwing into the crucible a little crude Antimony.

Glass of Antimony is a most violent emetic. This Glass, as well as Liver of Antimony, is employed in preparing Emetic Wine and Emetic Tartar.

It may be resuscitated, like the calces of Antimony, into a Regulus, by re-uniting it with a phlogiston. For this purpose it must be finely pulverized, thoroughly mixed with some black flux, and melted in a covered crucible. This Glass, as well as that of Lead, hath the property of greatly promoting the vitrification of matters that are to be scorified.

PROCESS IX.

_Kermes Mineral._

Break any quantity you will of Hungarian Antimony into little bits: put it into a good earthen coffee-pot: pour on it twice its weight of rain-water, and a fourth part of its weight of well filtered liquor of Nitre fixed by charcoal. Boil the whole briskly for two hours, and then filter the liquor. As it cools it will acquire a red colour, grow turbid, and leave a red powder on the filter.

Return your Antimony into the coffee-pot. Pour on it as much rain-water as before, and three fourths of the former quantity of the liquor of Fixed Nitre. Boil it again for two hours, and then filter the liquor. It will again deposite a red sediment. Return your Antimony into the coffee-pot: pour on it the same quantity of rain-water, and half the first quantity of the liquor of Fixed Nitre. Boil it again for two hours, and then filter the liquor as formerly. Wash all these sediments with warm water, till they become insipid; then dry them, and you have the _Kermes Mineral_.

_OBSERVATIONS._

If you recollect what we said concerning the property which Fixed Alkalis possess of uniting with Sulphur, both by fusion, and, when those Salts are resolved into a liquor, by boiling, and of forming therewith a Liver of Sulphur, which dissolves all metalline substances, you will readily comprehend the nature of this Kermes.

Antimony consists of a sulphureous and a reguline part. Therefore, if this mineral be boiled in a solution of a Fixed Alkali, such as Nitre fixed by charcoal, the Alkali will dissolve the Sulphur of the Antimony, and form therewith a Liver of Sulphur, which, in its turn, will dissolve the reguline part. Now, Kermes Mineral, prepared as above directed, is no other than a Liver of Sulphur combined with a certain quantity of Regulus of Antimony.

Mr. Geoffroy hath set this truth in the clearest light, by his accurate analysis of the Kermes Mineral. The experiments he made on that subject are circumstantially related in several Memoirs printed in the volumes of the Academy for 1734 and 1735. By combining Acids with the Kermes he demonstrated, 1. the existence of Sulphur in this compound; having separated from it a burning Sulphur, which cannot be mistaken for any other than the Sulphur of Antimony. In order to obtain this Sulphur pure, an Acid must be employed that will not only absorb the Alkali, but also perfectly dissolve the reguline part that might otherwise remain united with the Sulphur. _Aqua regia_ was the Acid which succeeded best with Mr. Geoffroy. 2. He also proved that there is a Fixed Alkali in the composition of the Kermes; seeing the Acids with which he precipitated the Sulphur became Neutral Salts, and just such as those very Acids combined with a Fixed Alkali would have constituted: that is, the Vitriolic Acid produced a _Sal de duobus_; the Nitrous Acid a regenerated Nitre; and the Marine Acid a regenerated Sea-salt. 3. Mr. Geoffroy demonstrated the reguline part of Antimony to be an ingredient in the Kermes; having procured therefrom an actual Regulus of Antimony, by fusing it with the black flux.

In preparing the Kermes it is necessary to renew the liquor from time to time, as above directed; because, when it is once impregnated with Kermes to a certain degree, it can take up no more; and consequently the same liquor cannot operate again on the Antimony. Experience hath shewn, that, if the doses above prescribed be applied, the liquor will after two hours boiling be sufficiently saturated with Kermes.

If the liquor in which the Kermes is dissolved be filtered while it is very hot, and almost boiling, it leaves nothing on the filter; the Kermes passing through with it: but as it cools it grows turbid, and gradually deposites the Kermes. Therefore it ought not to be filtered till it be cold; or, if it be filtered while it is boiling hot, in order to separate from it some coarse particles of Antimony not yet converted into Kermes, it must be filtered a second time when it is cold, in order to get the Kermes.

Though in the method usually practised for making Kermes, the Antimony is boiled only thrice, yet it does not follow that more Kermes may not be obtained from it, or that but little more would be obtained by a fourth and fifth boiling; on the contrary, it would yield considerably more. Mr. Geoffroy observed, that he got more Kermes by the second boiling than by the first, and still more by the third than by the second; and that the yield goes on increasing in this manner to a very great number of times, which he hath not determined. This increased effect arises from hence, that by multiplying the frictions of the little bits of Antimony against each other, new surfaces are exposed to the action of the Alkaline liquor, and furnish it with more Sulphur; while the addition of this sulphur renders the hepar more active and more penetrating; or, if you please, produces a new hepar every time the matters are boiled. When the Alkaline liquor is once saturated with Kermes, it ceases to act, and forms no new hepar; but it does not follow that its virtue is quite exhausted. To restore its ability of acting as well as at first, or nearly so, you need only let it cool, and deposite the Kermes dissolved in it. We owe this singular observation also to Mr. Geoffroy: he had the patience to go through no less than threescore and ten boilings with the same liquor, without adding any thing but rain water, to supply the place of what was dissipated by evaporation: and he always obtained a pretty considerable quantity of Kermes by each boiling, for the reason given above.

Boiling is not the only means of making Kermes. Mr. Geoffroy found the way of making it by fusion. For this purpose you must mix accurately one part of very pure Fixed Alkali, dried and pulverized, with two parts of Hungarian Antimony also pulverized, and melt the mixture. Mr. Geoffroy made use of a retort. When the mass is melted, it must again be pulverized, while it is still hot, and then put into, and kept in, boiling hot water for an hour or two; after which the liquor, now become saline and antimonial, must be filtered into another vessel filled with boiling water. Every ounce of Antimony treated in this manner yields, by thrice boiling the melted mass, from six drams to six drams and a half of Kermes; which differs from the Kermes made by boiling, only in that it is not quite so soft to the touch, having in every other respect the same qualities.

As Liver of Sulphur is made two different ways, to wit, by boiling and by fusion, and as the Kermes is nothing but a Liver of Sulphur in which the reguline part is dissolved; it follows that Kermes may be made by fusion as well as by boiling. It is necessary to pulverize the melted mass, and to steep it in boiling hot water for an hour or two, that the water may dissolve and divide it sufficiently to make the Kermes fine and beautiful.

With the same view, that is, to make it finer and more perfect, Mr. Geoffroy orders the water saturated with the Kermes made by fusion, to be received, when filtered, in a vessel full of other boiling hot water. He observed, that when the liquor impregnated with Kermes cools too fast, the Kermes that precipitates is much coarser. The warm solution of Kermes is diffused through the boiling-hot water into which it is filtered, and is thereby enabled to retain its heat so much the longer.

From what hath been said on the nature of Kermes, it plainly appears that there must be a great resemblance between it and the Golden Sulphur of Antimony, obtained from the scoria, either of plain Regulus of Antimony, or of the Liver of Antimony; this Golden Sulphur being no other than a portion of the Antimony combined with the Nitre alkalizated during the operation.

Yet there is a difference in the manner of precipitating these two compounds: for the Kermes precipitates spontaneously, on the bare cooling of the water in which it is dissolved; whereas an Acid is employed to precipitate the Golden Sulphur suspended in the water, with which the scoria of the plain Regulus of Antimony, or that of Liver of Antimony, hath been washed. This gives some ground to suspect that the reguline part is not so intimately united with the Liver of Sulphur in the Kermes, as in the scoriæ from which the Golden Sulphur is obtained.

PROCESS X.

_Regulus of Antimony dissolved in the Mineral Acids._

Compound an _aqua regis_ by mixing together four measures of Spirit of Nitre, and one measure of Spirit of Salt: on a sand-bath moderately heated place a matrass, into which pour sixteen times as much of this _aqua regis_ as you have Regulus to dissolve. Break your Regulus into little bits; and throw them successively one after another into the matrass, observing not to add a new one till that put in before is entirely dissolved: continue this till your Regulus be all used. By degrees, as the dissolution advances, the liquor will acquire a beautiful golden colour; which, however, will insensibly disappear, as the white fumes that continually ascend from it evaporate.

_OBSERVATIONS._

Regulus of Antimony is one of those metalline substances that dissolve with the greatest difficulty. Not but that most of the Acids attack and corrode it; but they do not make a clear, limpid solution thereof: they in some sort only calcine it, and this semi-metal, as fast as it dissolves, precipitates of its own accord in the form of a white magistery. In order to effect a complete dissolution thereof, it is necessary to employ an _aqua regis_ compounded as directed, and in the dose prescribed in the process, which is wholly taken from Mr. Geoffroy's Memoirs on Antimony mentioned above.

If, instead of the Regulus, small bits of crude Antimony be thrown into the _aqua regis_, the Acid will attack and dissolve the reguline part, and so separate it from the sulphureous part which it will not touch. When the dissolution is finished, the particles of Sulphur being now become lighter, because no longer united with the metalline part, will float upon the liquor. Being collected they form a true Sulphur, which seems no way different from common brimstone. This operation, you see, is a sort of Parting Process.

The Vitriolic Acid, whether concentrated or much weakened with water, does not act when cold either on Antimony or on its Regulus. This Acid only dims the splendour of the facets of the Regulus; but if one part of exceeding pure Regulus of Antimony be put into a retort, and four parts of clear concentrated Oil of Vitriol poured on it, as soon as the Acid is heated it turns brown, and emits a most suffocating smell of Sulphur, which increases as the Regulus is penetrated and corroded by the Acid.

On raising the fire, there separates from it a matter that seems mucilaginous; and when the Acid hath boiled some time, the Regulus is converted into a white saline mass, as Mercury is in the preparation of Turbith mineral. At the same time a little Sulphur sublimes into the neck of the retort. At last all the Oil of Vitriol passes over into the receiver, and leaves the Regulus in a white, spungy, saline mass in the retort. When the fire is out, the vessels unluted, and the receiver separated from the retort, there rises a white vapour like that of the smoking liquor of Libavius.

The saline mass left in the retort, after the operation, is found increased to near double its weight: this increased weight is owing to the Acid that hath united with the Regulus.

This combination of the Vitriolic Acid with the Regulus of Antimony is excessively caustic, and cannot, for that reason, be administered internally.

The purest Spirit of Salt hath no sensible effect either on Antimony or its Regulus: but if Antimony be coarsely pounded, it separates therefrom, though slowly, some light, sulphureous flakes.

The action of Spirit of Nitre on this metallic substance is more perceptible: by little and little it attacks the plates of the Antimony, which discharge a great number of air-bubbles. As the dissolution advances, the Acid acquires a greenish colour inclining to blue; and if there be not too much of it, it will be almost entirely imbibed by the Antimony, penetrate between its _laminæ_, and exfoliate them in the direction of the needles that compose them. If there be too much of the Acid, that is, if it rise above the Antimony, it will destroy these plates, and reduce them to a white powder.

But when the Acid is imbibed slowly, we discover between the swelled _laminæ_ little saline transparent crystals, that vegetate much in the same manner as those of the pyrites, in which small crystals of Vitriol are frequently observed, whose figures are not very well determined. These little crystals between the Antimonial plates are intermixed with yellow particles, which being carefully separated burn like common Sulphur.

All these useful observations, concerning the action of the Acids on Antimony and its Regulus, we owe likewise to Mr. Geoffroy; who advises the collecting a quantity of these little crystals in time; because they disappear soon after they are formed, being probably covered by the white powder, or magistery, which is continually produced as fast as the Nitrous Acid disunites and separates the needle-like fibres of the Antimony.

Mr. Geoffroy observed the same sort of crystals on the Regulus of Antimony, when substituted for crude Antimony in this experiment; but it requires a great deal of care to separate these crystals; for as soon as the air comes into contact with them they lose their transparency; and if you wait till the Regulus be in some measure converted into a magistery, they are not then to be distinguished.