Chymical disceptations, or, Discourses upon acid and alkali wherein are examined the object of Mr. Boyle against these principles : together with a reply to a letter of Mr. S. Doctor of Physick & fellow of the colleg of *** : wherein many errors are corrected, touching the nature of these two salts / by Fran. Andre, Dr. in Physick ..., faithfully rendered out of French into English by J.W. ; to which is added, by the translator, a discourse of phlebotomy shewing the absolute evils, together with the accidental benefits thereof, in some cases.

4. EXPERIMENT. Which proves that the Diversi∣ty of Savours depends upon the

different Mixture and particular nature of Acids 〈◊〉〈◊〉 Alkali's.

SIlver reduced into Cristals by spirit of Niter, which is a powerful Acid, become of an extream bitter Tast: Lead, on the contrary, dissolved in di∣stilled Vinegar and reduced in∣to salt, acquires the sweetness of sugar, &c.

I could bring several other Experiments to prove that the diversity of Odors and Savours depends upon the different Mixture of Acid and Alkali: But, tho' I have discoursed you thereof elsewhere, I shall yet bring you one more sufficient∣ly familiar: which is that of Wine: Wine having another Tast and another Smell before

it is fermented, than it has when it is fermenting, or after it is Fermented, for it changes by little and little its green Taste into a plesanter, and be∣comes at last sour, and loseth its temperament of Wine; and all these changes happens to it according 〈◊〉〈◊〉 the Acids and Al∣kalies which are found therein are more or less intangled, and 〈◊〉〈◊〉 as one of them is more or less exalted, and there is al∣most no odor or savor through which it doth not pass before it grows four.

There remains no more but that I speak two words of the passive Principles.

The Water is the first of these Principles, it serves (as I

have already told you) as a Vehicle to the Acid and Alkali salts; it serves also to dissolve them, and put them in Motion, because Salts act not except they are dissolved, Salia non agunt nisi dissoluta.

Water causes the Destructi∣on of Mixts, when it is found therein in too great a quanti∣ty, as it compacts them; and strictly unites their parts when it is found therein in a lesser quantity; and it fills up the empty spaces, which it meets with therein.

The Earth or Caput Mort. on the contrary being ex∣treamly porous and light, makes a great many vacancies in Bodies wherein it is found; but, on the other hand, it hin∣ders

that those bodies be not destroy'd by the abundance of flegm.

It is unnecessary to bring you a great many Experiments to prove that Water and Earth are found in all Bodies, and, That they are Principles thereto, but without any action: I believe you are sufficiently convinced thereof, and have several times observ'd, That there is no Bo∣dy from which we cannot draw some Flegm by Distillation, and which leave not some Earth after Calcination; and though we work never so much on Wa∣ter and Earth, it is Impossi to draw any other thing there∣from but water and Earth. You are not ignorant also. That rot∣ten wood which hath no Acid

and Alkali Salts, and which hath nothing but some Flegm and Earth, hath no more any action.

PYR.

I could wish you would a little longer explain what you mean by the words Fermentation and Precipita∣tion, whereof you make use so often.

EUBUL.

By the Word Fer∣mentation, I mean an Internal Motion of all the parts of Bo∣dies which are fermented in such Manner that they take no more the same place nor scitua∣tion as they had before, and that they change consequent∣ly, or at least alter very much the nature of the bodies which are fermented: as for the difference of Effervescence,

in which there is made only a simple Motion of the integral parts of Mixts by the force of some exteriour Agent, as Fire; the which parts re-take after∣wards the same scituation which thy occupied before, un∣less their natures and qualities be in any wise changed.

There are several sorts of fermentations in Nature; some are made with Effervescence, as that which happens upon the mixture of Oil of Vitriol with Oil of Tartar: and others are made without Efferves∣cence, as it happens in an Eg which a Hen hatcheth: and in common Water, when one casts thereinto some Drops of well-deflegm'd Spirit of Vitriol, and this Fermentation is known on∣ly

by the Heat which we feel at that instant: There are some which are made without Heat, as that which is made of Vitri∣ol dissolved in water with Oil of Tartar: There are some which are made with Fires and Flames, as the Fermentation which is made of Calx Vive in the time it is sprinkled with a little Vinegar: and others which are without Fire or flame, as are the ordinary Fermentati∣ons. There are still some sen∣sible and insensible; sensible, as the Fermentation of Spirit of Niter with Oil of Tartar: and insensible, as that of Wine, which sours.

PYR.

Whence comes it that there are so many sorts of Fer∣mentations?

EUB.

Either Bodies are fermen∣ted of themselves, as Wine; or they are fermented by means of a Ferment, as Dough with Leven; either the Acid Salts and Alkali Salts are Exalted, or else they are Intangled one in the other: and, in the Passive principles, one of them is ex∣alted, and the other Intangled; or, one of them is in a great quantity, and the other in a small quantity.

If the Acid Salts and Al∣kali Salts are each as pow∣erful as the other, the Fer∣mentation cannot be made without Heat and Effervescence, as of spirit of Niter with oil of Tartar; if, on the contrary, one of these two Salts is weak and the other strong, as are the Al∣kali

of Water, and the Acid of Oil of Vitriol well deflegm∣ed, there is only made a little heat without effervescence: if the Acid, which is mingled with the Alkali, is dis-intangled from its own Alkali and passive Principles; as the Acid of Oil of Vitriol, there is made a Fer∣mentation with Heat and Effer∣vescence: and, if on the con∣trary, the Acid is intangled, as in Vitriol in its Body; there is only made a Fermentation with Effervescence without Heat: In like manner, if these two Salts are exalted and dis-intangled one from the other, and from the passive Principles, they take fire at the same time that they ferment, as Calx vive doth when it is sprinkled with some

Vinegar. In a word, if these two Salts are weak, the Fermen∣tation is insensible.

There are few Fermentations made, but there is at the same time made a Precipitation; tho' there are several Precipitations made without Fermentation, as in the Precipitation which is done by Acids of Mercury sub∣limate dissolved in Water.

Precipitation is a Dis-uni∣nion of a dissolved Body from its dissolvant, in such manner that being separated therefrom it falls by its own weight to the bottom of the vessel which contain'd it.

Precipitation is made seve∣ral wayes; for, either it is an Acid which holds an Alkali in

dissolution; or, its an Acid which is dissolved by an Alka∣li, as it happens in the Com∣position of Regulus of Antimo∣ny, in which the Sulphur of Antimony, which is an Acid, is separated from the Regulus, and remains in the Foeces dissolved by the Alkali's of Tartar and Niter. If it is an Acid which holds an Alkali in dissolution; where the union is so perfect that there is not the least Pore empty (as in all the com∣pound Mineral Salts, as Vitriol) the Precipitation cannot be made but by an Alkali; or else, where the union is not so per∣fect, and there remains a great many Pores which are not filled by this Acid, as in cor∣rosive sublimate; The Precipi∣tation

may be done as well by Acids.