To the extent possible under law, the Text Creation Partnership has waived all copyright and related or neighboring rights to this keyboarded and encoded edition of the work described above, according to the terms of the CC0 1.0 Public Domain Dedication (http://creativecommons.org/publicdomain/zero/1.0/). This waiver does not extend to any page images or other supplementary files associated with this work, which may be protected by copyright or other license restrictions. Please go to http://www.textcreationpartnership.org/ for more information.
THE Mineral Waters arising near Epsom in Surrey, the chief of all the bitter Purging Waters, were found out by a Country Man, in or about the Year 1620.
For near, the first Ten Years, none but the Country People made use of them, and they only to wash External Ulcers.
Afterwards the Lord Dudley North, Fa∣ther to Francis the late Lord-Keeper, la∣bouring under a Melancholy Disposition, for which he had formerly Drank the Spaw-Waters in Germany, was resolv'd to try the Vertue of these Epsom Waters flat∣tering himself (I suppose) that he had found Chalybeate-Waters at his own Door.
However, tho' they answer'd not his desire and expectation as to their Nature, yet he did not repent of his Experiment, but from that time drank these Purging Waters, as a Medicine sent from Heaven, with abundance of success.
Many others, encouraged by his Exam∣ple, try'd the operation of these Waters; and amongst the first, Maria de Medicis, Mother to the Wife of King Charles I. the Right Honourable George Lord Goring, Earl of Norwich, and many other Persons of Quality.
These, and all others, who drank the Epsom-Waters, came not for Pleasure but Health, and therefore always consulted their own, or some Neighboring Physi∣cian, for the Rules they were to observe.
In a little while Physicians came of their own accord to these Waters by whose Au∣thority they acquir'd so great a Reputa∣tion, that 2000 Persons have been there
in one Day, to drink or divert them∣selves.
About 30 Years since, many of the In∣habitants of London, whose Business or Poverty obstructed their going to Epsom, had the Waters sent to them.
Thus the Ice being broke, others brought great quantities to Town, which they sold as well to Sick Persons as Apo∣thecaries, and continue still to do so.
No wonder then that so few sick People go to these Waters, 'tis not that the Mo∣dern Physicians esteem them less, but be∣cause the Numbers of such as Drink at home, and at other Wells of the same Nature, do every Day mightily encrease.
For a few Years after the Discovery of the Epsom-Waters was publish'd, others of the same sort (found out by Enquiry or Chance) grew into tolerable Repute and Use. The Names of the Principal are,
Besides these, the Curious and Inquisitive may discover very many more to us un∣known, especially if they take along with
them this Direction, that sweet Waters generally arise from the tops of Hills, but these from the Bottoms.
THese Waters have no taste, but a moderate bitterness, which is very sensible.
Some that have Travelled into Syria and Egypt, mention bitter Waters in those Countries; and St. James, in his Epistle, takes notice of sweet and bitter Waters, as very common things in the Eastern Parts; all which bitter Waters, 'tis pro∣bable, are of this sort.
These Fountains are not of an equal Strength nor Vertue, but some are much stronger than others; with the strongest Dullidge is justly reckon'd with the gentler Epsom.
These Waters in their Springs are with∣out smell, but kept some Days or Weeks in Vessels close stopp'd, they putrifie and stink, especially in Summer time; which will happen to all Waters, and sometimes also to the clearest Spring Water, as we
are told by those that Sail near the Equa∣tor.
Pour a little of this Water to Sirrup of Violets, and 'twill remain blue and un∣chang'd, as if 'twere mix'd with common Spring-water.
By the adding Lime water, it gives a whitish Muddy colour, as if some drops of Milk were mix'd with it, and the white parts will, in about an hours time, subside in the form of a cloudy curdling, produc'd from the Union of the chalky Lexivial, and the acidity of the Cathartick Salts.
All these Waters will curdle Milk, if it be added to them when they are hot, or boiling, but not at all if mix'd when they are cold.
The Waters of any of these Wells, eva∣porated in a glazed Earthen, or any other proper Vessel, will yield a kind of a Cream a top, and a sediment at the bottom of the Vessel, of both together, 6, 8, or 10 Drams from a Gallon.
This Cream is of an Ash colour, Stony substance, and resembles Plaister, but cer∣tainly not at all Lixivial, for every one knows that the Lapis Calcarius, or Lime-Stone, calcin'd, altho' actually cold, will grow very hot by pouring Water upon them, and emit a very great and thick
fume, and that apply'd to any part of the Body 'twill burn. Therefore Chirurgeons use it for a Potential Cautery; but the fore-mentioned Cream calcin'd in a Cruci∣ble, and Water pour'd upon it, causes neither smoak nor heat, nor does it ac∣quire any the least Pungency.
Sometimes, as in Acton-Waters, the thin Minute Particles of which it consists Will be very resplendent and brittle, and wholly insipid, tho' Calcin'd as aforesaid, yet by the pouring on any acid Liquor, chiefly by Spirit of Nitre, an Ebullition, with a sensible heat, will be excited.
The lesser part of this Sediment is like in substance to the before-describ'd Cream; the remainder is purely Saline, but com∣pounded of two kinds of Salts, one a Mu∣riatick or Sea-Salt, the other a Salt proper or special to these Waters, whose Nature and Vertues I here design to treat of.
In Epsom-Waters, the Muriatick Salt is about the 20th part of the whole Saline Composition; it is something more in Dullidge, and in most of the fore-mention∣ed Springs.
In its biting Tast, as well as in the Fi∣gure of its Chrystals, 'tis not unlike Com∣mon Salt; whence it is that Waters, in which there is less of this Muriatick Salt, purge not so strongly as others.
The other Salt, as we have said before, is the proper, or peculiar Salt of the Pur∣ging Waters; 'tis made after the same manner as all Lixivial Salts, viz. by Eva∣porating, Filtring, and Chrystalizing, Calcination only excepted. In this Pre∣paration, the Earthy or Plaistery part, is first to be separated from the Saline; then the Muriatick Salt, and a yellow and thick Liquor from the proper Salt of the Waters.
THis Salt, if it be rightly prepar'd, is of a delicate whiteness equal to new fall'n Snow.
This bitter Salt is much more evident in the Salt it self, in a dry Form, than in the Water, and smites the Tongue with a very penetrating Pungency, but without any Acrimony.
If you dissolve a Dram of this Salt in a Pint of Common Water, which is its Na∣tural proportion, 'twill have the same pro∣perty of curdling Milk, and be ennobled with the same bitter Tast and Purging Vertue peculiar to its Mineral Water.
And therefore 'tis not improperly di∣stinguish'd
from the Sal Mirabilis, (made of Oil of Vitriol, and Common Salt) and from all other Salts, by the Name of the Bitter Purging Salt.
This bitter Purging Salt, from the dif∣ferent manner of evaporating its Water, or degree of Cold, to which 'tis afterwards exposed, and other circumstances, will shoot into Crystals of a greater or lesser Magnitude. But let the Dimensions be what they will, the Figure is the same; for most of their Crystals, if they shoot not too thick, are small rectangular Prisms, with four parallel sides; the two opposite sides something flatter than the other. Sometimes they have two more sides, and are Sexangular; but these are so small that the naked Eye can hardly discover 'em.
Their length is about half an Inch, but their thickness not above a fith, sixth or seventh part of their length; their Basis, a lump of the same; the Summit very different, having sometimes three, but for the most part four sloping Plains, and with the fore-mention'd parallel sides make obtuse Angles, or pointed, or of∣tener sharpned, like a Pen Knife: One of the sloping Plains is generally bigger than the other three taken together, and of a
Pentangular or Sexangular Figure; the opposite to this Quadrangular or Pentan∣gular; the other two Triangular and less; the last, sometimes invisible, without a Microscope.
These Cristals, in their Oblong Figure, do most resemble Salt-Petre; in their Rectangular they come nearest to Sea-Salt.
This bitter Salt, dissolv'd in common Water, and standing some Days in a Glass Vessel, shoots into Branches like little Trees round the sides of the Glass: To the producing this Figure, the before-describ'd Cristals of this Salt and of Sal Nitre (the points of which are terminated sometimes into Right, sometimes into Acute Angles) are very proper; the sloping Plain of one Cristal joyning to the pa∣rallel Plain of the others. Which I have also demonstrated to be done in the Ge∣neration of Leaves, by the Figure of their proper Salts. Plant. Ang. 9. lib. 4. p. 1. c. ult.
Where note by the way, That in that Discourse I have set down the Figures of Sal Nitri and other Salts, not altogether as they appear to us, but, probably, as they do exist in the Plants themselves.
Five Drams of this bitter Purging Salt, mixt in a Vial with half an Ounce of
common Water; and shaken together, by that Agitation only and the gentle Heat of the Hand in Winter, will all presently dissolve, except a few Grains; by which you observe it to be more dissolvable than any other Salt.
'Tis distinguish'd also by its Specifick Gravity from all other Salts; 'tis heavier than Allom, lighter than common Salt, and than Nitre, as we shall hereafter prove in the fifth Chapter.
A dissolution of this Salt, and Salt of Tartar, and any other Urinous or Lixivial Salt, will generate a white Coagulum, or a Nuetral Salt, of the taste of neither, but something Styptick.
Strong and new Oil of Vitriol, poured upon this Salt, will cause a moderate Ebul∣lition; from whence we may conclude it to be of an Alkaline Principle, and in some manner Lixivial.
But if you add any other Liquor that I know of, either Acid or Alkali, to this Salt, 'twill neither ferment nor grow hot.
This Salt in a Crucible, with a strong fire, will melt and swell like Allom into a white Porous and boiling Calx.
But this Calx will (except about a 40th part of the whole) dissolve in a sufficient quantity of common Water, which the
Lapis Calcarius, or Lime-Stone, will not.
This Calx, in a Crucible, with a vehe∣ment fire for an hour, will be as hard as Alabaster, nor will it afterwards be soft∣ned by the Air: Much otherwise 'tis with the Lime-Stone, which Calcin'd, and ex∣pos'd to the Air, falls to Powder.
Altho' by this Calcination it loses some part of its weight, yet its bitterness con∣tinues, and is rather increas'd.
The Calx of the bitter Purging Salt, by the affusion of Spirit of Salt, or any other Acid, will presently ferment, which is more or less conspicuous according to the strength of the aforesaid Spirit; from whence also we may allow it to be in some sort Lixivial.
From a Pound of this Salt Distill'd in a Glass Retort well Luted, with a Rever-beratory Fire, you'll have in the Receiver a little above half a pound of an Acid Spi∣rit in smell and tast, every way equal to common Spirit of Salt.
Oil of Vitriol pour'd upon common Spirit of Salt, yields a dark and smoaky Vapour, which will likewise happen, if you drop the same Oil very strong into the Spirit of the Purging Salt.
'Tis very well known, that all the Cha∣lybeate
Waters will change to a Purple, by the addition of Galls, as will White-wine Vinegar, tho' more obscurely; but the infusion of Galls will be in no wise alter'd by the Spirit of the Purging Salt, tho' an Acid, nor by the Spirit of {sulphur}, or Oil of Vitriol, from whence, as well as many other ways, the different Nature of these, and other Acids, may be shown.
I took 8 Glass Bottles of River-Water, and with some drops of Sirrup of Violets colour'd them all blue alike; one of which I let stand without any thing else added to it. To a 2d I put a little Sal Nitri; to a third some of the bitter Purging Salt; to a fourth a little Lime-Water; to the fifth a dissolution of the Calx of the Purging Salt; to the sixth an infusion of white Tar∣tar; to the seventh the Distill'd Spirit of the Purging Salt; to the last, a little of both Lime-Water and the Purging Salt.
In the three first, the Cerulous colour remain'd only a little faded.
In the 4th and 5th, the Cerulous co∣lour was converted to a manifest Green; in the former turbid and paler, in the lat∣ter like a Smarag'd, very deep and clear.
In the 6th and 7th it turn'd purple; in the first obscure, but the latter was like a true Amethyst.
The green colour, in the 4th and 5th, vanish'd in about 3 hours, but the 5th was much deeper, and more durable.
From this manifold Experiment we may observe, that as Nitre, although by accension it will yield a fix'd Lixivial Salt, and by Distillation an Acid Spirit, yet has neither a Lixivial, nor Acid tast, there∣fore gives neither green nor purple colour to the Sirrup; so we may conclude the Purging bitter Salt to consist of like princi∣ples, that is not solely Acid, but also Al∣kalious, and a little Lixivial.
But it may be evidently demonstrated, that its principles do partake of both, by the acidity of its Spirit, and the green co∣lour; its Calx gives Sirrup of Violets like Aqua Calcis, and other Lixivial Liquors.
In the last Bottle the colour was deeper and more durable, by the combination or union of the twofold Alkalious Salt, the bitter Purging Salt, and the Calcarious, as Ink is made by the union of two Astrin∣gents.
And 'tis very plain, that the existence of these Salts, and their efficacy in altering Colours, depends not on the fire, because the infusion of white Tartar will, like the Spirit of the Purging Salt, die the Sirrup of a purple colour.
Lastly, Take notice that I call the Al∣kaline Principle in this Purging Salt po∣tentially, and after a sort Lixivial.
For, as we have observ'd in this Chap∣ter, you can perceive no Lixivial tast even in the Calx of this Salt, which does not hinder, but that an Alkaline Principle may be in this Salt, as appears from the fore cited Experiments, tho' it has never endured the fire, but after Calcination it is prov'd to be I know not how Lixivial.
I call it Lixivial, tho that, nor any other Name in Use that I know of, is justly adapted to its Nature, for there is a want of proper Words to express our meanings in nothing so much as in Philosophy, such as should lead us through the Footsteps of Nature, and Intelligibly express its admi∣rable variety.
FRom the fore-cited Experiments, and those we shall now mention rightly understood and compar'd, 'twill evidently appear that the Purging bitter Salt, tho' it may have some Qualities common to other Salts, does differ in its Nature and Species from all other Salts.
Very many have confidently affirm'd it to proceed from an Aluminous Minera, but inconsiderately, for from whence is it they prove it, but because they coagulate Milk, which is no reason at all, for by the same ridiculous Argument, Vinegar, Wine, Beer, and whatever curdles Milk, must be Aluminous.
Nor does it appear from hence, that like Allom, when melting, it swells and rises in bubbles, for Borax melted will have the same Elevation, but Borax does not curdle Milk, therefore is not Aluminous, nor from thence can the bitter Purging Salt be so.
Moreover, from an Ounce of Allom cal∣cin'd half an hour in a Crucible, there will remain half an Ounce of Calx. To this pour a sufficient quantity of common Wa∣ter to dissolve the Saline parts, and there will remain about 52 Grains of an insipid and simple Earth at the bottom of the Vessel, which is six times as much as the like quantity of the Calx of the bitter Salt will leave behind it.
Nor is the Spirit of Allom Distill'd with a strong Fire any thing like the Spirit of this Salt, for the first has a greater acrimo∣ny, and much less grateful tast; and which is worth Observation, a Fetid
smell very like to the Spirit or Gass of Sulphure.
The tast likewise of this bitter Purging Salt and Allom is so different, that nothing can be more; for that of Allom is austere and has no bitterness, the other no man∣ner of austerity but wholly bitter.
Besides, they are evidently distinguish'd by their Natural Figures for the Chrystals of Allom, the Factitious at least consider∣ing its Altitude are something flattish, and consist of 8 Planes; two, viz. those at top and bottom, Sexangular and Parallel: The greater and less sides of these Planes are so placed alternately, that the 3 great∣er answer to the 3 less. About these are plac'd 6 Quadrangular Planes with une∣qual sides and angles, the greater bending towards the Centre of the Chrystal, and the less accordingly
How very unlike this is to the before-describ'd Figure of the Purging Salt, may easily appear by comparison.
Nor can this bitter Purging Salt with more Justice be reckon'd amongst the Mu∣riatick or common Salts, which well pu∣rify'd has a very different tast from the Purging Salt, and also from Allom; its Figure is likewise as different, for it shoots not long ways, but contracted almost in the form of a Cube.
Besides, the Purging Salt calcin'd in a Crucible, with a strong Fire, emits no visi∣ble vapour, nor loses more than half of its weight; but common Salt thus calcin'd, as 'tis much more fluid, so it ascends in thick smoaky vapours, leaving scarce an 18th part of the whole in the Crucible.
Neither (which may seem strange) does the Spirit of common Salt Distill'd, as the Spirit of the Purging Salt, coagulate Milk, unless added to it when 'tis Boiled.
To be certain of this, I try'd the fol∣lowing Experiment.
To a Pint of River Water, impregnated with a Dram of the bitter Purging Salt, and boiling, I threw in 3 or 4 Spoonfuls of Milk, and let it boil again; presently the curdled Milk swam upon the Water.
It did the same with as much of the Spi∣rit of the bitter Purging Salt.
Lastly, Instead of the Spirit of the Pur∣ging Salt, I us'd the Spirit of common Salt, and that much stronger than the for∣mer Spirit, in the same proportion and method, but the Milk remained fluid in its Natural state without any coagulation.
NOR does this Salt differ less from all kinds of Nitrous Salts; from which, by its bitter tast alone, its enough distin∣guish'd.
Nor less by its Figure, for the Chrystals of Nitre shoot not into four corner'd Pa∣rallel Planes, but always into six; nor into right Angles, but obtuse, and their tops seldom terminate in 4 sloping Planes, but mostly in 2, and sometimes in 6, and those more equal than in the Purging bitter Salt.
The Purging bitter Salt thrown into the Fire is not at all inflamable but Nitre burns with a bright flame and roaring noise, till the most part of it evaporates.
I have said the most part of it, nor do I retract my assertion, for in the 3d Chapter we have observ'd about a 20th part to re∣main after the deflagration, which is in no wise Nitrous, but Lixivial, from Wood-Ashes mix'd with it by the Nitre-Makers.
But further, the bitter Salt in a Spoon, held over the flame of a Candle, will melt
in a moment, and bubble up as if thrown in to the fire; but Nitre, with such a heat; will scarcely melt, but take up at least 8 times the space of the other, and emits a most resplendent flame.
On the contrary, tho' Nitre melts with difficulty, 'tis when melted much more fluid, for in a Crucible, in a strong fire, it boils not like Allom, or the bitter Salt, but flows like Rosin or melted Metals.
From Nitre melted in a Crucible arise thick Exhalations, which you never see from the bitter Salt, tho' in the strongest Fire.
Add likewise, that they differ from one another in their power of coagulating Milk.
For half a Dram of the Purging Salt, thrown into half a Pint of Milk, will turn it very gray; but Nitre mix'd after the same manner, tho' in much greater pro∣portion, has no such effect.
The solubility of Nitre, as we have be∣fore prov'd, is two parts in three less than the Purging Salt, for half an Ounce of common Water will, in the Winter, by agitation and a warm hand, dissolve not above a Dram and half of Nitre.
Its gravity is likewise very different, which appears by the following Experi∣ment.
I put Oil of Turpentine into a Cylindar to the height of 3 Fingers; I then put in two Ounces of the Purging Salt, which rais'd the Oil a Finger higher, but from an equal weight of depurated Nitre, the Oil was elevated not higher than 3 fourths of a Finger; therefore the bitter Purging Salt is a 4th part lighter than Nitre.
But Water impregnated with the Pur∣ging Salt occupies a less space, its bulk considered, than the same quantity with as much Sal Nitri dissolved in it.
That is, Water instead of Oil mix'd with the Salts in a Vial; when they are dissolv'd, the former subsides lower than the latter.
Lastly, I Distill'd Dantzick Vitriol, Sal Armoniack, and a like quantity of the bit∣ter Salt, instead of Nitre, in order to make the Aqua Regia. Now if this had been a Nitrous Salt, this Water wou'd, like Aqua Regia, have dissolv'd Gold, but we could find no such power in this Water.
Nor is it the Nitre of the Ancients, for 'tis nothing like that of the Egyptians so often mention'd by Hypocrates; something like which is describ'd by Dioscorides and Pliny to be of a purple colour and biting; nor that of Etius, like Earth calcin'd and quench'd with Wine.
Nor, lastly, can it be reckon'd with the Sal Calcarius; for the Purging Salt, or Water only, coagulates Milk with a much harder Curd, and greater plenty of Se∣rum, than the Lime Water will.
And, if that Power of Coagulation were equal, how many Liquors have we mention'd that curdle Milk, which are neither Calcarious nor Aluminous.
Spirit of Nitre, dropt into the Cream that swims atop of the Lime-Water, or upon Lime it self, will cause a visible Ebullition; but the same Spirit will have no such Effect upon the Purging Salt.
There can be no where more diffe∣rence in the taste of Things, than be∣tween the Purging Salt and the Calcari∣ous; for the one is Lixivial and Sweet; the other, as it were Cold and Bitter.
Lime will, by pouring a little Water upon it, presently fall to Powder. On the contrary, the Calx of the Purging Salt powder'd, will, by the same means, run immediately into a hard Substance, and in a few Moments be like a Stone.
Lamb's-Conduit Water, mixt with Lime-Water, will in a very little time grow white, with a dark clowdy Curd∣ling; as it will with the Purging Wa∣ters:
But, if you mix it with Water im∣pregnated with the Calx of the Purging Salt, no Muddiness nor Colour will fol∣low.
Common Water impregnated with this Salt, and afterwards evaporated, will restore you the whole quantity you dis∣solv'd, without any waste; but Lime-Water evaporated, the Salt is for the most part transmuted into a stony and tastless Substance: The Cause of which is, that the Saline Parts of the Aqu. Calcis do so intimately imbrace and unite with any other Aerial Salt, that they make a third Nurtral Salt; as in Oil of Anisseeds and Vitriol, shaken together, you have a Refine, properly so call'd, which, if you wash, will yield you no manner of taste.
This may be illustrated by the follow∣ing Experiment. I kept Lime-Water in a Glass close stopt with a Cork, and as much in an open Vessel, for a Week or longer; that in the stopt Vial had no Cream upon it; but that in the open Vessel where the Air could freely arrive at the Water, was cover'd with an insipid and stony Cream.
But Water, in which the Purging Salt is dissolv'd, kept in an open Vessel, and
many Days expos'd to the Air, will have no Cream at all on its surface: And that which appears in boiling the Purg∣ing Waters, is not in the least Calcarious, as we have formerly prov'd.
Add also the very different solubility of these Salts; for half an Ounce of the Bitter Purging Salt will be easily, and without Heat or much Agitation present∣ly dissolv'd in six times its quantity of Water. But to the dissolution of so much of the Calcarious Salt, is required two Gallons and a half of Water, which is 640 times its weight. For so much com∣mon Water is necessary to edulcorate an Ounce of Calx Vivens; which done, there remains in the bottom of the Vessel about half an Ounce of pure white and Insipid Calx.
But the Bitter Purging Salt is eminent∣ly distinguish'd from the fore-mention'd (if there were no other way) by its Me∣dicinal Virtues, as we shall evidently de∣monstrate, in the latter Part of this Tract, where we speak of its Use.
In the mean time, we do not deny a small Portion, as well of Nitre and com∣mon Salt, as of a stony Substance, may be contained, not only in the Purging Wa∣ters, but even in the Salt it self. And,
indeed, 'tis probable that no Body, exi∣stent in Nature, is purely simple. Sil∣ver, every one knows, is mixt with Cop∣per or Lead; Gold, with Silver in the same Mine Vein; nay, and Metallick Mass: But it does not follow, that Sil∣ver and Copper, or Gold and Silver, do hereby constitute a third Species; but the two, or more, separable Metals exist together.
Nor, can we inferr an Identity of Bo∣dies from their agreement in some quali∣ties; for Lead and Gold do so agree; both are solid, opacque, ductile, fusible, heavy Bodies, &c. and therefore are both Metals; but nothing is Gold, that has not all the qualities of Gold.
For Gold does not differ more ways, nor in a more eminent manner from Lead, than the Bitter Purging Salt is di∣stinguish'd from all other Salts; and therefore is in its own Nature the most Noble.
THE most special Qualities of this Salt, that we have already describ'd, are a taste gently and almost simply Bit∣ter; and of all sorts, that we know, most resembling the Crystals of Silver in simi∣litude of Taste. For these, indeed, are bitter, but very much so, and not without some Austerity joined with it.
I have in another place observ'd the Lapis Calaminaris to have some Qualities common with Silver, therefore I dropp'd into the Powder of this Stone some drops of Spirit of Nitre; and the fermentation over, I wash'd the mixture with common Water. This Water, like the Chrystals of Silver, is not only very styptick but bit∣ter, and is the only bitter Mineral that I know of, except the Salt of Luna, and the Purging Salt. But whether the Purging Salt do arise from any Silver Minera, whol∣ly or in part so, or from the Lapis Calami∣naris, or rather from any other, I leave undetermined, being never able to get any of the true Minera of this Salt.
But this is very plain from the fore∣mentioned Experiments, that the Bitter Purging Salt is compounded of some parts in their nature Acid, and others Alkaline, and a little Lixivial.
In Salts compounded of various Princi∣ples, the Proportion, the Nature and the Union of those Principles are to be con∣sider'd.
Some Acid Particles are frequently found in Lixivial Salts, but in a small pro∣portion.
But in Tartar, which is the Salt of Wine, the Saline Parts are much lesser than the Acid, which exist in a much greater proportion.
And 'tis almost the same in the Bitter Purging Salt, with this difference only, That in the former the Acids are actually mix'd with the Alkaline, but in the latter Potentially.
Moreover, all Lixivial Salts are Acri∣monious, but those commonly call'd Testa∣ceous are not without reason accounted the more gentle.
As likewise are some Acid Liquors, such as the Juice of Wood-Sorrel, a Disso∣lution of the Cream of Tartar, &c. but the Purging Salt is gentler than any of these.
Indeed, by Distillation it gives an Acid Spirit, but this Acid Taste is not percep∣tible till its Principles are intimately dis∣solv'd and divided by a most violent Fire.
For the Salt it self has neither Acrimo∣ny nor Acidity.
Nor is it Tastless, but very subtle and biting, and therefore a most Efficacious Medicine.
Its Admirable Subtilty will appear by its penetrating any Earthen Vessel, if not very well Glaz'd about the bottom; of which, on the outside, there will be a woolly or hoary Concretion in colour like an Amethyst.
The Principles of this Salt are also more closely united than in Tartar, and afford many other Remedies. For the Union is so firm, that one of its parts, viz. its Acid, cannot be above the one half of it separated from the other, and that not without a reverberatory Fire. Whence 'tis, that when other gentle Purges frequently elude the Physicians expecta∣tion, this does very seldom or never de∣ceive him.
For such Medicines do work most up∣on the Humours of the Body, which are least alterable by those Humours: In
the number of which this Salt, and other Minerals, are to be accounted.
Last of all; This Salt, tho' it does consist of different Principles, is very pure, if rightly and diligently prepar'd; inso∣much that it does not retain the thou∣sandth part of any extraneous Body with it self.
For, if you evaporate destill'd Water, impregnated with an Ounce of this Salt, 'twill yield not a Particle of any Heterogeneous Salt, stony Sediment, or Cremor, but the very same Ounce of most pure Salt.