Experimental notes of the mechanical origine or production of fixtness.

EXPERIMENTS, AND OBSERVATIONS, About the Mechanical Production OF TASTS.

TO make out the Mechanical Origine or Production of Sa∣pors, as far as is necessary for my present purpose, 'twill be expedient to premise in general, that, accor∣ding to our notion of Tasts, they may depend upon the bigness, figure and motion of the saporifick corpu∣scles, considered separately, and as the affections of single and very mi∣nute particles of matter; or else in a state of conjunction, as two or more

of these affections, and the particles they belong to, may be combined or associated, either among themselves, or with other particles, that were not saporous before. And as these Coalitions and other Associations come to be diversified; so the Tasts, resulting from them, will be altered or destroyed.

But, to handle these distinctly and fully, were a task not onely too dif∣ficult and long, but improper in this place, where I pretend to deliver not Speculations, but matters of Fact: in setting down whereof nevertheless, to avoid too much confusion, I am content, where I can doe it readily and conveniently, in some of my Tri∣als, to couch such references as may best point at those Heads, whence the Mechanical explications may be derived, and consequently our Do∣ctrine confirmed.

By Tast considered as belonging to the Object, (under which Notion I here treat of it,) I mean that quality, or whatever else it be, which ena∣bles

a body by its operation, to pro∣duce in us that sensation, which we feel or perceive when we say we tast.

That this something, whether you will call it a quality, or whatever else it be that makes or denominates an object saporous, or rather (if I may be allowed a barbarous term) sapo∣rifick, may so depend upon the shape, size, motion, and other Mechanical affections of the small parts of the tasted body, and result from the as∣sociation of two or more of them, not excluding their congruity or in∣congruity to the organs of Tasting, may be made probable by the fol∣lowing Instances.

EXPER. I.

To divide a Body, almost insipid, into two Bodies of very strong and very differing Tasts.

'TIS observed, that Salt-peter refined, and by that purifica∣tion freed from the Sea-salt that is wont to be mingled with it, does rather cool the tongue, than make any great saporifick impressions on it. And though I will not say, that it is, as some have thought, an insipid bo∣dy; yet the bitterishness, which seems to be its proper tast, is but very faint and languid. And yet this almost insipid body, being distilled by the way of Inflammation, (which I else∣where teach,) or even by the help of an additament of such clay as is it self a tastless body, will afford a Ni∣trous spirit, that is extreamly sharp or corrosive upon the tongue, and will dissolve several Metals them∣selves, and a fixt salt, that is like∣wise

very strongly tasted, but of a tast altogether different from that of the Spirit, that is extreamly sharp or corrosive upon the tongue; and ac∣cordingly, this salt will dissolve di∣vers compact bodies that the other will not work on, and will precipi∣tate divers metals and other con∣cretes out of those solutions, that have been made of them by the Spi∣rit.

EXPER. II.

Of two Bodies, the one highly Acid and corrosive, and the other Alkalizat and fiery, to produce a Body almost insipid.

THis may be performed by the way I have elsewhere mentio∣ned of composing Salt-peter. For if upon a liquour of fixt Nitre, made per Deliquium, you warily drop good Spirit of Nitre, till it be just enough to satiate the Alkaly, (for if there

be too much or too little, the Expe∣riment may miscarry,) we may by a gentle evaporation, and sometimes without it, and that in a few minutes, obtain Crystals, which, being dried after they have been, if it be need∣full, freed from any adhering par∣ticles, (not of their own nature,) will have upon the tongue neither a sharp nor an alkalizate tast, but that faint and scarce sensible bitterness that be∣longs to Salt-peter, if it be pure Salt-peter; for the impure may perhaps strongly relish of the common Salt that is usually contained in it.

The like production of Salt-peter we have sometimes made in far less time, and sometimes indeed in a trice, by substituting, in stead of the fixed Salt of Nitre, the saline parts of good Pot ashes, carefully freed by solution and filtration from the earthy and feculent ones.

I have sometimes considered, whe∣ther the Phaenomena of these two Ex∣periments may not be explicated by supposing them to arise from the new

magnitudes and figures of the parti∣cles, which the fire, by breaking them, or forcibly rubbing them one against the other, or also against the Corpuscles of the additament, may be presumed to give them; as if, for example, since we find the larger and best formed Crystals of Nitre to be of a prismatical shape with six sides, we should suppose the corpuscles of Nitre to be little prisms, whose angles and ends are too obtuse or blunt to make vigorous and deep impressions on the tongue; and yet, if these lit∣tle prisms be by a violent heat split, or otherwise broken, or forcibly made as it were to grind one another, they may come to have parts so much smaller than before, and endowed with such sharp sides and angles, that, being dissolved and agitated by the spittle that usually moistens the tongue, their smalness may give them great access to the pores of that organ, and the sharpness of their sides and points may fit them to stab and cut, and perhaps sear the nervous

and membranous parts of the organ of Tast, and that variously, according to the grand diversities, as to shape and bulk, of the saporifick particles themselves. And this being granted, it seemed further conceivable, that when the Alkalizate and Acid parti∣cles come to be put together in the fluid mixture, wherein they swam, many of them might, after a multitude of various justlings and occursions, meet with one another so luckily and opportunely, as to recompose little prisms, or convene into other bodies, almost like those that made up the Crystals of Nitre, before 'twas expo∣sed to the fire. To illustrate which, we may conceive, that, though a prism of iron may be so shaped, that it will be wholly unfit to pierce the skin; yet it may be so cut by trans∣verse planes reaching to the opposite bases or ends, as to afford wedges, which, by the sharpness of their ed∣ges, may be fit both to cleave wood, and cut the skin; and these wedges, being again put together after a re∣quisite

manner, may recompose a prism, whose extreams shall be too blunt to be fit for the former use. This may be also illustrated by the breaking of a dry stick circularly cut off at the ends, which though it is unapt, whilst intire and of that bulk, to prick the hand; yet if it be violently broken, the ragged ends of it and the splinters may prove stiff, slender, and sharp enough to pierce and run into the hand: To which di∣vers other such Mechanical Illustra∣tions might be added. But, since I fear you think, as well as I, the main conjecture may not be worthy any farther prosecution, I shall not insist any longer on it. And because the historical part of these Experiments was for the main delivered by me al∣ready in the Essay about the Analysis and Redintegration of Nitre, I shall now proceed to other Trials.

EXPER. III.

Of two Bodies, the one extreamly bitter, and the other exceeding salt, to make an insipid mixture.

TO make this Experiment, we must very warily pour upon Crystals made of Silver, dissolved in good Aqua fortis or Spirit of Nitre, strong brine made of common salt and water. For the mixture of these two being dried, and afterwards brought to fusion in a Crucible, and kept a competent while in that state, will afford a tough mass, the Chymists call Luna Cornea, which you may lick di∣vers times, and scarce judge it other than insipid; nor will it easily be brought to dissolve in much more piercing Menstruums than our spit∣tle, as I have elsewhere shewn.

EXPER. IV.

Of two Bodies, the one extreamly sweet, and the other salter than the strongest Brine, to make an insipid mixture.

THE doing of this requires some skill and much wariness in the Experimenter, who, to perform it well, must take a strong solution of Minium, made with an appropriated Menstruum, as good Spirit of Vine∣gar, or else Saccharum Saturni it self, dissolved in a convenient Vehicle; and then must have great care and caution to put to it, by degrees, a just proportion of strong Spirit of Sal Armoniac, or the like Urinous Spirit, till the whole be precipitated; and if the two former tasts are not sufficiently destroyed in the mixture, it may be dried and fluxed, as was a∣bove directed about Luna Cornea.

EXPER. V.

Of an insipid Body and a sour one, to make a Substance more bitter than Gall or Aloes.

THis is easily performed by dis∣solving in strong Spirit of Nitre or good Aqua fortis as much pure Silver as the Menstruum will take up; for, this solution being filtrated, has been often esteemed more bitter than so much Gall or Wormwood, or any other of those simples that have been famous for that quality: And if the superfluous moisture be abstra∣cted, you may by coagulation obtain Crystals of Luna, that have been judged more strongly bitter than the solution it self. And that the cor∣puscles of these Crystals should leave a far more lasting tast of themselves, than the above-mentioned bitter bo∣dies are wont to doe, will not seem so marvellous, as I remember some that tried have complained; if we

take notice, how deep the particles of these Crystals may pierce into the spungy organs of Tast, since, if one does but touch the pulp or nail of ones finger, (first a little wetted with spittle or otherwise,) with the pow∣der of these Crystals, they will so penetrate the skin or nail, and stick so fast there, that you cannot in a reasonable time wash the stain off of the skin, and much less off of the nail, but it will continue to appear many hours on the former, and many days on the other.

EXPER. VI.

Of an insipid Body and a highly corrosive one, to make a Substance as sweet as Sugar.

THis is easily done, by putting upon good Minium purified A∣qua fortis or Spirit of Nitre, and let∣ting them work upon one another in a gentle heat, till the liquour have

dissolved its full proportion of the metal. For then, if the ingredients were good, and the operation rightly performed, the Menstruum would have a sweetness like that of ordina∣ry Saccharum Saturni. But 'twas not for nothing that I intimated, the ingredients should be also pure and good in their kind; for, if the Minium be adulterated, as often it is, or the Spirit of Nitre or Aqua fortis be mingled, as it is usual before it be purged with Spirit of common Salt or other unfit ingredients, the ope∣ration may be successless, as I have more than once observed.

EXPER. VII.

Of obtaining without addition from the sweetest Bodies, Liquours corrosive enough to dissolve Metals.

IF Sugar be put into a sufficiently capacious Retort, and warily di∣stilled, (for otherwise it will be apt

to break the Vessel) it will afford, among other things, a copious red Spirit, which, being slowly rectified, will lose its colour, and come over clear. The Caput Mortuum of the Sugar, which I have more than once had of an odd Contexture, may be found either almost or altogether insipid. And though the Spirit will be of a very penetrant tast, yet it will be very far from any kind of sweet∣ness; and though that liquour be thought to be homogeneous, and to be one of the Principles of the ana∣lized Sugar, yet (as I have elsewhere shewn) I found it to be a mixture of two Spirits; with the one of which, besides bodies of a less close Texture, I dissolved (even in the cold) crude Copper, as was easie to be seen by the deep and lovely co∣lour of the solution. And to these sour Spirits, afforded by Sugar it self, we have restored a kind of Sac∣charine sweetness, by compounding them with the particles of so insipid a body as Minium; part of which

they will in digestion dissolve. A like Spirit to that distilled from Su∣gar may be obtained from Honey; but in regard of its aptness to swell exceedingly, Chymists are not wont to distill it without Sand, Brick, or some other additament.

EXPER. VIII.

To divide a Body, bitter in the highest degree, into two Substances, the one extreamly sour, and the other per∣fectly insipid.

THis is easily done by putting some fine Crystals of Luna into a good Retort, and then distilling them in a Sand-furnace, capable of giving them so strong a fire, as to drive away all the spirits from the Silver. For, this remaining behind, according to its metalline nature, will be insipid, and the spirits, that are driven away from it, will unite in the Receiver into an acid and cor∣rosive Menstruum.

EXPER. IX.

To produce variety of Tasts in one insipid Body, by associating it with divers Menstruums.

AS this operation may, upon the account I elsewhere mention, be serviceable to investigate the fi∣gures of the particles of dissolved metals and other bodies; so 'tis ve∣ry fit to manifest, what we would here have it shew, how much Tast may be diversified by, and conse∣quently depend upon, Texture; since a body that has no tast, may, in conjunction with sapid bodies, give them strong tasts all differing from one another, and each of them from that which the saporous bodies had before. I could propose divers ways of bringing this to trial, there being several insipid bodies, which I have found this way diversifiable. But because I remember not, that I have met with any mineral, that is

dissoluble by near so many saline Menstruums, as Zinke, I look on that as the most fertile Subject to afford Instances to our present purpose. For I have found, that it will be dissolved not onely by Aqua fortis, Aqua Regis, Oil of Vetriol, Spirit of Nitre, Spirit of Salt, and other mi∣neral Menstruums, but also by Ve∣getable Spirits, as distilled Vinegar, and by Animal ones too, as Spirit of Sal Armoniac; though the one be Acid, and the other Urinous. And if the several Solutions, which may be made of this mineral, by so many dif∣fering liquours, be compared, the number of their differing tasts will suffice to make good the Title of the Experiment.

EXPER. X.

To produce variety of Tasts with one Menstruum, by associating it with insipid Bodies.

THis Proposition a Mathemati∣cian would go near to call the Converse of the foregoing; and as it may serve as well as that to discover the structure of the minute parts of divers metalline and mineral bodies; so it may not onely as well, but bet∣ter than that, serve us to illustrate the Corpuscularian Doctrine of Tasts, by shewing us, that a single, and, as far as Chymistry teaches us, a simple body, endowed with a peculiar tast, may, by being compounded with others, each of them insipid of it self, produce a considerable number of differing tasts. There may be more Instruments than one made use of in this Trial; but of those that are known, and we may easily obtain, the most proper are Spirit of Nitre,

and good Aqua fortis: For that, with refined Silver, will make a So∣lution bitter as Galls; with Lead, 'twill be of a Saccharine sweetness; with that part of Tin, which it will keep dissolved, (for the greatest 'tis wont but to corrode and praecipitate) it produces a tast very distant from both the former, but not odious; with Copper, it affords an abominable tast; with Mercury and Iron, it af∣fords other kinds of bad Tasts. Nor are Metals the onely mineral bodies it will work upon: For, 'twill dissolve Tin-glass, Antimony, Brass; to which I could add Emery, Zinke, and other bodies whereon I have tried it. All which together will make up no de∣spicable number of differing Tasts.

EXPER. XI.

Of two Liquours, the one highly cor∣rosive, and the other very pungent and not pleasant, to compose a Body of a pleasant and Aromatick Tast.

THis Experiment, which I else∣where mention to other purpo∣ses, does in some regards better suit our present design, than most of the foregoing; since here the Corrosive Menstruum is neither mortified by fixt nor urinous Salts, supposed to be of a contrary nature to it; nor yet, as 'twere, tired out nor disarm'd by corroding of metals or other solid bodies. The Experiment being some∣what dangerous to make at first in great, it may suffice for our present turn, to make it in the less quantity, as follows.

Take one ounce of strong Spirit of Nitre, or of very good Aqua fortis it self, and put to it by little and little, (which caution if you neglect, you

may soon repent it,) and another ounce of such rectified Spirit of Wine, as, being kindled in a Spoon, will flame all away: When these two liquours are well mixt, and grown cold again, you may, after some di∣gestion, or, if hast require, without it, distill them totally over together, to unite them exquisitly into one li∣quour, in which, if the operation have been well performed, the cor∣rosive particles of the Salts will not onely loose all their cutting acidity, wherewith they wounded the palat; but by their new composition with the Vinous Spirits, the liquour ac∣quires a Vinous tast, that is not one∣ly not acid or offensive, but very pleasing, as if it belonged to some new or unknown Spice.

EXPER. XII.

To imitate by Art, and sometimes even in Minerals, the peculiar Tasts of natural Bodies, and even Vegetables.

THis is not a fit place to declare, in what sense I do or do not admit of Souls in Vegetables, nor what I allow or deny to the Seminal or Plastick principle ascribed to Plants: But perhaps it will not be er∣roneous to conceive, that, whatever be the Agent in reference to those Tasts, that are said to be specifick to this or that Plant, that, on whose immediate account it is or becomes of this or that nature, is a complication of Mechanical Affecti∣ons, as shape, size, &c. in the par∣ticles of that matter which is said to be endowed with such a specifick tast.

To illustrate this, I thought it ex∣pedient, to endeavour to imitate the tast of some Natural bodies by Artifi∣cial

Compositions or Preparations, but found it not easie, beforehand to be assured of the success of such Trials: And therefore I shall content my self here to mention three or four Instances, that, except the first, are rather Observations than such Ex∣periments as we are speaking of.

I remember then, that, making some Trials to alter the sensible Qua∣lities of Smell, Tast, &c. of Oil of Vitriol, and Spirit of Wine, I obtai∣ned from them, among other things that suited with my design, a certain Liquour, which, though at first plea∣sant, would, at a certain nick of time, make one that had it in his mouth think it had been imbued with Gar∣lick.

And this brings into my mind, that a skilful person, famous for making good Sider, coming one day to ad∣vise with me, what he should doe to heighten the tast of it, and make it keep the longer, complained to me, that having, among other trials, put into a good Vessel full of juice of

Apples a certain proportion of Mu∣stard-seed, with hopes it would make the Sider more spirituous and pick∣ant, he found, to his wonder and loss, that, when he came to draw it, it stank of Garlick so rank, that eve∣ry body rejected it.

I remember also, that, by fermenting a certain proportion (for that we found requisite) of semen Dauci with Beer of Ale, the Liquour had a very pleasant Relish of Limon-pills.

But that seems much more consi∣derable, which I shall now add; That, with an insipid Metal and a very cor∣rosive Menstruum, one may com∣pound a tast, that I have several times observed to be so like a Vege∣table, that I presume it may deceive many. This may be done by dissol∣ving Gold, without any gross Salt, in the mixture of Aqua fortis and the Spirit of Salt, or even in common A∣qua Regis, made by dissolving Sal Ar∣moniac in Aqua fortis. For if the Experiment be happily made, one may obtain either a Solution or a

Salt, whose austere tast will very much resemble that of Sloes, or of unripe Bullace. And this tast, with some little variety, I found in Gold dissolved without any distilled Li∣quour at all; and also, if I much for∣get not, in Gold that by a peculiar Menstruum I had volatilized.

The last Instance I shall give of the imitation of Tasts, I found to have been, for the main, known to some ingenious Ladies. But to make the Experiment succeed very well, a due proportion is the principal Cir∣cumstance, which is wont to be neg∣lected. I cannot readily call to mind that which I found to succeed best; but the Trial may be indifferently well made after such a manner as this:

Take a pint or a pound of Malaga or Canary Sack, (for though French and the like Wines may serve the turn, yet they are not so proper;) and put into it a drachm or two of good odoriferous Orrice Roots, cut into thin slices, and let them infuse

in the Liquour a convenient time, 'till you perceive that they have gi∣ven it a desired tast and smell; then keep the thus perfumed Wine exact∣ly stopped in a cool place: According to which way, I remember, that (when I hit on the right proportion of Ingredients, and kept them a due time in infusion) I had many years ago a Wine, which, being coloured with Cocheneele, or some such tingeing ingredient, was taken for good Ras∣berry-Wine, not onely by ordinary persons, but, among others, by a couple of eminent Physicians, one of whom pretended to an extraordinary criticalness of palate on such occa∣sions; both of them wondering, how at such an unlikely time of the year, as I chose to present them that Li∣quour among others, I could have such excellent Rasberry-Wine: Some of which (to add that by the by) I found to preserve the specifick tast two or three years after it was made.