The Salt of Lead hath a saccharine taste, which hath procured it

the name also of Sugar of Lead. For this reason when Wine begins to

turn sour, the ready way to cure it of that disagreeable taste is,

to substitute a sweet one which is not disagreeable to the taste, by

mixing therewith Ceruse, Litharge, or some such preparation of Lead:

for the Acid of the Wine dissolves the Lead, and therewith forms a

Sugar of Lead, which remains mixed with the Wine, and hath a taste

which, joined with that of the Wine, is not unpleasant. But, as Lead is

one of the most dangerous poisons we know, this method ought never to

be practised; and whoever employs such a pernicious drug deserves to be

most severely punished. Yet something very like this happens every day,

and must needs have very bad consequences; while there is nobody to

blame, and those to whom the thing may prove fatal can have no mistrust

of it.

All the retailers of Wine have a custom of filling their bottles on a

counter covered with Lead, having a hole in the middle, into which a

leaden pipe is soldered. The Wine which they spill on the counter, in

filling the bottles, runs through this pipe into a leaden vessel below.

In that it usually stands the whole day, or perhaps several days; after

which it is taken out of the leaden vessel, and mixed with other Wine,

or put into the bottle of some petty customer. But, alas for the man

to whose lot such Wine falls! He must feel the most fatal effects from

it; and the danger to which he is exposed is so much the greater, the

longer the Wine hath stood in the leaden vessel, and thereby acquired

more of a noxious quality. We daily see cruel distempers among the

common people, occasioned by such causes, which are not sufficiently

attended to.

Wine that is not kept in close vessels is apt to turn sour very soon,

especially in the summer; and the retailers of Wine have observed that

their drippings, thus collected in vessels of Lead, are not liable

to this inconvenience. This is what hath established among them the

practice I am speaking against. As they see only the good effects

thereof, and know nothing of its ill consequences, we cannot be angry

with them. It is natural to think, that, as Lead hath the property

of keeping Wine cool, it may by that means prevent its growing sour

for some time; and persons who are not versed in Chymistry can hardly

suspect that Wine is preserved from being pricked, only by being

converted into a kind of poison. Yet this is the very case: for Lead

doth not hinder the Wine from growing sour; but, uniting with its

Acid, as soon as it appears, and forming therewith a Sugar of Lead,

changes the taste thereof as hath been said, and hinders the Acid from

affecting the palate.

Hence it appears how much it were to be wished that the use of those

counters covered with Lead were abolished entirely. I am informed, by

a Chymist zealous for the public good[17], that he represented this

matter to the Magistrates several years ago. It is not to be doubted,

that, when the dealers in Wine know the ill consequences attending this

practice, they will with pleasure sacrifice the small benefit they

receive from it to the public safety.

[17] Mr. Rouelle, whom I have had occasion to mention several times

in this work with the honour which he deserves, and with whom I went

through a course of Chymistry, when I was a Student in Medicine. It

must be observed, to the praise of this ingenious Artist, that he is

the first Frenchman that ever gave Courses of Chymistry. In these he

explains the operations according to the true and sound Theory of the

Science, drawn from the writings of Beccher, Stahl, Juncker, Boyle,

Boerhaave, Hoffman, and many other excellent Chymists, whom it would

be tedious to mention here, as well as from the Memoirs of the most

celebrated Academies, particularly those of the Academy of Sciences

at Paris.

It is easy to prove whether or no a suspected Wine contains Lead. You

need only pour into it a little Oil of Tartar _per deliquium_; or, if

you have not that at hand, a lye of the ashes of green wood. If there

be any Lead dissolved in it, the liquor will immediately grow turbid,

and the Lead will precipitate in the form of a white powder; because

the Sugar of Lead it contains, being a Neutral Salt, whose basis is a

metal, is decompounded by the Fixed Alkali, which separates that metal

from the Acid. Lead thus separated from the Acid of Vinegar by an

Alkali is called _Magistery of Lead_.

Ceruse, or White Lead, is also a very dangerous poison. It is a pigment

very much used, being the only White that can be applied with Oil.

This White is the most common, or, perhaps, the only cause of those

dreadful colics with which painters, and all that work in colours, are

frequently afflicted. This induced me to examine all the substances

capable of affording a White, in order to find one, if possible,

which might be substituted for White Lead: but, after a vast number

of experiments, I had the mortification to be convinced, that all

Whites, even the brightest and most beautiful, which are not metallic,

produce nothing, when ground with Oil, but greys, or dirty yellows.

There is still something to be hoped for in Whites obtainable from

certain metallic substances: but, as every one of those matters may be

suspected of some noxious quality, long experience alone will remove

our just apprehensions of danger from every thing afforded by such

substances.

To return to the Salt of Lead: it may be decompounded by distillation

without addittament. In order to perform this, you must put the Salt

of Lead into a glass or stone retort, leaving a full third thereof

empty, and distil in a reverberating furnace with degrees of fire. A

spirit rises, which fills the receiver with clouds. When nothing more

will come over with a fire that makes the retort red-hot, let the

vessels cool, and then unlute them. You will find in the receiver, an

austere liquor, which is inflammable, or, at least, an inflammable

Spirit may be obtained from it, if about one half thereof be drawn off

by distillation in a glass alembic. The retort in which the Salt of

Lead was decompounded contains at the end of the operation, a blackish

matter: this is Lead, which will resume its metallic form on being

melted in a crucible; because the Acid by which it was dissolved, and

from which it hath been separated, being of a very oily nature, hath

left in it a sufficient quantity of phlogiston.

What is most remarkable in this decomposition of Salt of Lead is the

inflammable Spirit which it yields, though the Vinegar which entered

into the composition of the Salt seemed to contain none at all.

CHAP. VII.

_Of the_ PUTRID FERMENTATION _of_ VEGETABLE SUBSTANCES.

PROCESS I.

_The Putrefaction of Vegetables._

Fill a hogshead with green plants, and tread them down a little; or,

if the vegetables be dry and hard substances, divide them into minute

parts, and steep them a little in water to moisten them: then leave

them, or the green plants, in the vessel, uncovered and exposed to the

open air. By degrees a heat will arise in the center of the vessel,

which will continue increasing daily, at last grow very strong, and

be communicated to the whole mass. As long as the heat is moderate,

the plants will retain their natural smell and taste. As the heat

increases, both these will gradually alter, and at last become very

disagreeable, much like those of putrid animal substances. The plants

will then be tender as if they had been boiled; or even be reduced to a

kind of pap, more or less liquid according to the quantity of moisture

they contained before.

_OBSERVATIONS._

Almost all vegetable matters are susceptible of putrefaction; but some

of them rot sooner, and others more slowly. As putrefaction is only a

species of fermentation, the effect whereof is to change entirely the

state of the Acid, by combining it with a portion of the earth and Oil

of the mixt, which are so attenuated that from this union there results

a new saline substance in which no Acid is discernible; which on the

contrary hath the properties of an Alkali, but rendered Volatile; it is

plain, that, the nearer the Acid of a plant set to putrefy is to this

state, the sooner will the putrefaction of that plant be completed.

Accordingly all plants that contain a Volatile Alkali ready formed, or

from which it can be obtained by distillation, are the most disposed to

putrefaction.

Those plants, in which the Acid is very manifest and sensible, are less

apt to putrefy; because all their Acid must undergo the change above

specified. But vegetable matters, whose Acid is entangled and clogged

by several of their other principles, must be still longer elaborated,

before they can be reduced to the condition into which complete

putrefaction brings all vegetables. The earthy and oily parts, in which

the Acids of these substances are sheathed, must be attenuated and

divided by a previous fermentation, which, from those parts subtilized

and united with the Acid, forms an Ardent Spirit, wherein the Acid is

more perceptible than in the almost insipid, or saccharine juices, out

of which it is produced. The Acid contained in the Ardent Spirit must

be still further disengaged, before it can enter into the combination

of a Volatile Alkali: consequently the Ardent Spirit must undergo a

sort of decomposition; its Acid must be rendered more sensible, and

be brought to the same condition as the Acid of plants in which it

manifests all its properties.

Hence it appears, that the spirituous and acetous fermentations are

only preparatives, which nature makes use of, for bringing certain

vegetable matters to putrefaction. These fermentations therefore must

be considered as advances towards that putrefaction, in which they

terminate, or rather as the first stages of putrefaction itself. This

is the opinion of Mr. Stahl, who hath treated this subject with great

sagacity, and thrown much light upon it.

Mr. Boerhaave is not altogether of the same mind. He considers

putrefaction as something foreign to fermentation; as an operation

independent of it, and very different from it. He gives the title

of fermentation to that intestine and spontaneous motion only which

produces an Ardent Spirit, and changes it into an Acid. He founds

his opinion on this, that the circumstances attending putrefaction

are different from those which accompany spirituous and acetous

fermentation; that the product of putrefaction is very different from

the products of these fermentations; and lastly, that all vegetable and

animal substances are susceptible of putrefaction, whereas only some

kinds of them are capable of fermentation properly so called.

Mr. Boerhaave is so far right, that we ought not to confound together

operations which differ in several respects, and result in different

productions; but Mr. Stahl's opinion must nevertheless be looked

on as highly probable, or rather absolutely true. For it doth not

necessarily follow, from the difference between the circumstances

and productions of fermentative motions, that the operations have no

relation to, or connection with, each other. They may nevertheless

be considered as different steps of one and the same operation: and

if all vegetable and animal matters are not susceptible of the three

degrees of fermentation, we can only infer from thence that there

are mixts, in which the whole work of fermentation is yet to do; and

that there are others whose principles are so disposed that they are

in the same condition as if they had already undergone the first, or

even the second, degree of fermentation; and consequently such mixts

are susceptible only of the second, or perhaps of the third, degree of

fermentation.

Mr. Stahl therefore says very judiciously, that, far from denying

putrefaction to be a fermentation, we ought on the contrary to consider

all fermentation as no other than putrefaction. Matters susceptible

of the spirituous and acetous fermentation do but pass through these

previous alterations in their way to complete putrefaction. On this

principle, Wine and Vinegar are only liquors that had begun to putrefy,

but were stopt at the first or second stage of their putrefaction. This

is so true, that, if a fermenting liquor be left to itself in the open

air, and in a due degree of heat, it will proceed directly, without any

stop, to perfect putrefaction.

The acetous fermentation is attended with more heat than the

spirituous, and the putrid with still more than the acetous. The heat

of putrefying plants is sometimes so considerable, that, when they are

not too moist, and are stacked up in great heaps, they take fire and

burn violently. Of this there are frequent instances in hay-ricks.

PROCESS II.

_Putrefied Vegetable Substances analyzed._

Put the putrefied plants you mean to analyze into a glass cucurbit, and

set it in a sand-bath. Fit to it a head; lute on a receiver; distil

with a gentle fire, and a limpid fetid liquor will come over. Continue

the distillation till the matter contained in the retort be almost dry.

Then unlute your vessels, and keep the liquor you find in the receiver

by itself. Put the matter remaining in the cucurbit into a retort,

and distil with a graduated heat. There will rise white vapours; a

pretty considerable quantity of liquor nearly like that of the former

distillation; a Volatile Salt in a concrete form; and a black oil,

which towards the end will be very thick. In the retort there will

remain a black charred matter, which being burnt in the open air will

fall into ashes, from which no Fixed Alkali can be extracted.

By means of a funnel separate your oil from the aqueous liquor.

Distil this liquor with a gentle heat. You will by this means obtain

a Volatile Salt like that of animals; of which you may also get some,

by the same means, from the liquor which came over in the first

distillation.

_OBSERVATIONS._

This analysis shews the changes which putrefaction produces in

vegetable matters. Scarce any of their principles are now to be

discerned. They now yield no aromatic liquor; no Essential Oil; no

Acid; and consequently no Essential Salt, Ardent Spirit, or Fixed

Alkali: in a word, whatever their natures were before putrefaction,

they are all alike when they have once undergone this fermentative

motion in its full extent. Nothing can then be obtained from them but

Phlegm, a Volatile Alkali, a fetid Oil, and an insipid Earth.

Almost all these changes are owing to the transmutation of the Acid,

which is depraved by putrefaction, and combined with a portion of the

Oil and subtilized Earth of the mixt; so that the result of their union

is a Volatile Alkali. Now, as the Fixed Alkali, found in the ashes of

unputrefied plants, is only the most fixed part of their earth and

of their Acid, closely united together by the igneous motion, it is

not surprising that, when all the Acid, with a part of the earth, is

subtilized and volatilized by putrefaction, no Fixed Alkali can be

found in the ashes of putrefied Vegetables. The alteration which the

Acid suffers by the putrefactive motion is, in my opinion, the greatest

it can undergo, without being entirely destroyed and decomposed, so as

to be no longer a Salt.

We have seen it, in the Mineral kingdom, in its greatest purity and

strength. Its combination with Oil, and the other alterations its

undergoes, in the Vegetable kingdom, have shewn it weakened and

disguised. The changes it suffers by the spirituous and acetous

fermentation, have exhibited it in other forms. And lastly,

putrefaction disfigures it completely, and, in some sort, changes its

very nature, so that it cannot be distinguished. In the animal kingdom

we find it nearly in the same condition: for though the Vegetable

substances, on which animals feed, do not undergo direct putrefaction,

in its full extent, before they are converted into animal juices, yet

they suffer most of the alterations produced by putrefaction; so that

when they have acquired the qualities necessary to their becoming an

actual nutritious animal juice, they are within one step of complete

putrefaction. For this reason all animal substances are very apt to

putrefy, and are unsusceptible of the first degrees of fermentation.

But this discussion belongs to the animal kingdom, of which we are

now going to treat in the third part of these Elements; the theory of

putrefaction serving to introduce it, and naturally leading us to it.

[Illustration: Decorative Scroll.]

PART III.

OF OPERATIONS ON ANIMAL SUBSTANCES.

CHAP. I.

_Of_ MILK.

PROCESS I.

_Milk separated into Butter, Curd, and Whey; instanced in Cow's Milk._

Put new Cow's milk into a flat earthen pan, and set it in a temperate

heat. In ten or twelve hours time there will gather on its surface a

thick matter, of a somewhat yellowish white: this is called _Cream_.

Gently skim off this Cream with a spoon, letting the milk you take up

with it run off. Put all this Cream into another vessel, and keep it.

The milk thus skimmed will not be quite so thick as before: nor will

it be of such a dead white, but have a little blueish cast. If all the

Cream be not separated from it, more will gather on its surface after

some time, which must be taken off as the former. In two or three days

the skimmed milk will coagulate into a soft mass called _Curd_, and

then it tastes and smells sour.

Cut this Curd across in several places. It will immediately discharge

a large quantity of _Serum_. Put the whole into a clean linen cloth;

hang it up, and underneath it set a vessel to receive the Serum as it

drops. When the aqueous part hath done dripping, there will remain in

the filter a white substance somewhat harder than the curdled milk.

This substance is called _Cheese_, and the _Serum_ separated from it is

known by the name of _Whey_.

_OBSERVATIONS._

The milk of animals, that feed only on vegetables, is of all animal

matters the least removed from the vegetable nature. The truth of

this will be demonstrated by the experiments we shall produce by and

by, for the further analysis of milk. For this reason we judged, with

Mr. Boerhaave, that it was proper to begin the analysis of animals by

examining this liquor.

Most Chymists justly consider Milk as of the same nature with Chyle.

Indeed there is great reason to think, that, except some small

differences to be afterwards taken notice of, these two matters are

nearly the same. They are both of a dead white colour, like that of an

emulsion; which proves that, like emulsions, they consist of an oily

matter divided, diffused, and suspended, but not perfectly dissolved,

in an aqueous liquor.

It is not surprising that these liquors should resemble emulsions; for

they are produced in the same manner, and may very justly be called

_Animal Emulsions_. For how are vegetable substances converted into

Chyle and Milk in an animal body? They are bruised, divided, and

triturated by mastication and digestion, as perfectly, at least, as

the matters pounded in a mortar to make an emulsion; and must thereby

undergo the same changes as those matters; that is, their oily parts,

being attenuated by those motions, must be mixed with and lodged

between the aqueous parts, but not dissolved therein; because they do

not, in the bodies of animals, meet with saline matters, sufficiently

disentangled and active, to unite intimately with them, and by that

means render them soluble in water.

Nevertheless Chyle and Milk, though produced in the same manner as

emulsions, and very much resembling them, differ greatly from them in

some respects; owing chiefly to the time they remain in the bodies of

animals, their being heated while there, the elaborations they undergo

therein, and the animal juices commixed with them.

New Milk hath a mild agreeable taste, without any saline pungency; nor

hath any Chymical trial discovered in it either an Acid or an Alkali.

Yet it is certain that the juices of plants, out of which milk is

formed, contain many saline matters, and especially Acids: accordingly

Milk also contains the same; but the Acids are so sheathed and

combined, that they are not perceptible. The case is the same with all

the other liquors intended to constitute part of an animal body: there

is no perceptible Acid in any of them.

Hence it may be inferred that one of the principal changes which

vegetables undergo, in order to their being converted into an animal

substance, consists in this, that their Acids are combined, entangled,

and sheathed in such a manner that they become imperceptible, and exert

none of their properties.

Milk left to itself, without the help of distillation, or any

additament whatever, undergoes a sort of decomposition. It runs into a

kind of spontaneous analysis; which doth not indeed reduce it to its

first principles, yet separates it into three distinct substances, as

the process shews; namely, into Cream, or the buttery fat part, into

Curd or Cheese, and into Serum or Whey: which shews that those three

substances of which Milk consists, are only mixed and blended together,

but not intimately united.

The first parts, being the lightest, rise gradually to the surface of

the liquor as they separate from the rest: and this forms the Cream.

Cream, as skimmed from the surface of Milk, is not however the pure

buttery or fat part; it is still mixed with many particles of Cheese

and Whey, which must be separated in order to reduce it into Butter.

The most simple, and at the same time the best method of effecting

this, is daily practised by the country people. It consists in beating

or churning the Cream, in a vessel contrived for that purpose, with

the flat side of a circular piece of wood, in the center of which a

staff is fixed. One would think that the motion, impressed on the Cream

by this instrument, should rather serve to blend more intimately the

particles of Butter, Cheese, and Whey, of which it consists, than to

separate them from each other; as this motion seems perfectly adapted

to divide and attenuate those particles. But, if we consider what

passes on this occasion, we shall soon perceive that the motion by

which Butter is churned is nothing like triture: for churning is no

other, properly speaking, than a continually repeated compression, the

effect whereof is to squeeze out from amongst the buttery particles

those of Cheese and Whey mixed therewith; by which means the particles

of Butter are brought into contact with each other, unite, and adhere

together.

Milk, whether skimmed or no, grows sour of itself, and curdles in a few

days. When it is newly curdled, the Cheese and Whey seem to be united,

and to make but one mass: but these two matters separate spontaneously

from each other, with the greatest ease, and in a very short time.

The acidity, which Milk naturally contracts in the space of a few

days, must be considered as the effect of a fermenting motion, which

discovers in that liquor an Acid that was not perceptible before.

This, properly speaking, is an acetous fermentation, which Milk passes

through in its way to putrefaction; and it soon follows, especially if

the Milk be exposed to a hot air.

If, instead of leaving Milk to grow sour and curdle of itself, an

Acid be mixed therewith, while it is yet sweet and newly milked, it

immediately coagulates; which gives reason to think, that its curdling

naturally is the effect of the Acid, which discovers itself therein as

it grows stale.

The coagulation of Milk may also be considerably accelerated, by

setting it in a sand-bath gently heated; or by mixing therewith a

little of what, in the language of the Dairy, is called _Runnet_; which

is nothing but some curdled and half-digested Milk taken from the

stomach of a Calf: or both these methods may be employed at once, which

will produce the effect still more expeditiously.

It is not difficult to find out the cause of these effects. The Runnet,

which is Milk already curdled and grown sour, is an actual ferment to

sweet Milk, disposing it to turn sour, much more readily: for though

Milk, when thus hastily curdled by the Runnet, hath not a manifestly

acid taste, yet it is certain that this Acid begins to exert itself.

The proof thereof is, that, being exposed to the same degree of heat

with Milk equally new, that is not mixed with this ferment, it turns

sour much sooner. As to the effect of heat in coagulating Milk, there

is nothing extraordinary in it: we know how much it promotes and

accelerates all fermentative motion. The whole of this perfectly agrees

with what we said before concerning fermentation.

Fixed Alkalis also coagulate Milk; but at the same time they separate

the Whey from the Cheese, which floats on the liquor in clots. They

give the Milk a russet-colour inclining to red; which may arise from

their attacking the fat part.

The separation of Milk into Butter, Cheese, and Whey, is a kind of

imperfect analysis thereof, or rather the beginning of one. In order

to render it complete, we must examine each of these substances

separately, and find the principles of which they consist. This we

shall endeavour to do in the following process.

PROCESS II.

_Butter analyzed by Distillation._

Into a glass retort put the quantity of fresh Butter you intend to

distil. Set the retort in a reverberatory; apply a receiver, and let

your fire be very gentle at first. The Butter will melt, and there

will come over some drops of clear water, which will have the peculiar

smell of fresh Butter, and shew some tokens of Acidity. If the fire be

increased a little, the Butter will seem to boil: a froth will gather

on its surface, and the phlegm, still continuing to run, will gradually

come to smell just like Butter clarefied in order to be preserved. Its

Acidity will be stronger and more manifest than that of the first drops

that came over.

Soon after this, by increasing the fire a little more, there will rise

an Oil, having nearly the same degree of fluidity as fat Oils; but it

will grow thicker as the distillation advances, and at last will fix in

the receiver when it cools. It will be accompanied with some drops of

liquor, the Acidity whereof will always increase, while its quantity

decreases, as the distillation advances.

While this thick Oil is distilling, the Butter contained in the retort,

which at first seemed to boil, will be calm and smooth, without the

least appearance of ebullition; though the heat be then much greater

than when it boiled. Continue the distillation, constantly increasing

the fire by degrees as you find it necessary for the elevation of the

thick Oil. This Oil, or rather this kind of Butter, will be at last

of a russet-colour. There will rise along with it some white vapours

exceeding sharp and pungent.

When you observe that nothing more comes over, though the retort be

quite red-hot, let the vessels cool, and unlute them. You will find in

the receiver an aqueous acid liquor, a fluid Oil, and a kind of fixed

brown Butter. Break the retort, and you will find therein a charred

matter; the surface of which, where it touched the glass, will be of a

shining black, and have a fine polish.

_OBSERVATIONS._

The analysis of Butter proves that this substance, which is an oily

matter in a concrete form, owes its consistence to the Acid only, with

which the oily part is combined: that is, it follows the general

rule frequently mentioned above in treating of other oily compounds;

the consistence whereof we shewed to be so much the firmer, the

more Acid they contain. The first portions of Oil that come over in

the distillation of Butter are fluid, because a pretty considerable

quantity of Acid rose before them, which being mixed with the phlegm

gives it the Acidity we took notice of.

This Oil, being freed from its Acid, and by that means rendered fluid,

rises first; because it is by the same means rendered lighter. The

kind of Butter that comes over afterwards, though it be fixed, is

nevertheless far from having the same consistence as it had before

distillation; because it loses much of its Acid in the operation.

This Acid is what rises in the form of white vapours. These vapours

are, at least, as pungent and irritating as the Sulphureous Acid or

Volatile Alkalis: but their smell is different: it hath a resemblance,

or rather is the same, with that which rises from Butter, when it

is burnt and browned in an open vessel. But, when concentrated and

collected in close vessels, as in the distillation of Butter, they are

vastly stronger: they irritate the throat so as to inflame it; they are

exceeding sharp and pungent to the smell, and are so hurtful to the

eyes that they quickly inflame them, as in an ophthalmy, and make them

shed abundance of tears. The great volatility of this Acid is entirely

owing to a portion of the phlogiston of the Butter with which it is

still combined.

It may be asked why Butter, or the oily part of Milk which hath the

consistence of a fixed Oil, is more replete with an Acid than the Oils

of the vegetables whereof the Milk was formed; as these Oils are almost

all fluid, which indicates their containing less Acid before than after

they were digested in the body of an animal. This must appear the more

extraordinary, because the Acid contained in the liquors of animals is

sheathed and imperceptible, and consequently incapable of combining

with the Oils of vegetables so as to give them this consistence.

I think it will be easy to give a satisfactory answer to this question,

if it be considered, that the Oils, which exist in the vegetable juices

whereof the Milk is formed, are far from being combined with the whole

Acid of those vegetables; because there is hardly a plant that doth not

yield a great deal of Acid, even without the help of fire. Now, there

is reason to think, that one of the principal effects of digestion is,

to combine and unite this Acid, with the oily parts of vegetables, more

intimately than it was before.

The further we advance in the analysis of animals, the more we shall

be convinced, that, in the different elaborations, which vegetable

substances undergo in order to their being changed into the nutritious

juices of animals, nature employs all her powers to expel, destroy, or

at least, weaken and blunt the Acids, so as to render them absolutely

imperceptible. One of the best means by which she can effect this, is

the combining and uniting them intimately with the oily parts: and

this operation she probably begins in digestion. She gets rid of most

part of the Acids contained in the aliments, by thus uniting them with

the Oils contained in those aliments. Hence arises the consistence

of Butter, which is the fat part of Milk, that is, of a liquor

half-changed into an animal juice.

This explication furnishes us also with the reason why Acids agree so

ill with people of weak and delicate constitutions. The motion and heat

in their bodies is not sufficient to effect a due combination of the

Acids with the Oils. Hence it comes to pass, that, during and after

digestion, they find in their bowels the bad effects of those Acids, in

the disorder commonly called the _Heart-burn_. Hence also it is that

such people receive great benefit from the use of Absorbents, which

uniting with the Acids neutralize them, and relieve nature when she has

not strength enough herself to get the better of them.

To return to our analysis of Butter: we took notice in the process that

Butter seems to boil with a very moderate heat at the beginning of the

distillation, and that in the course of the operation the ebullition

ceases entirely, though the heat be then greatly increased; which

is contrary to the general rule. The reason is, that butter, though

a seemingly homogeneous mass, contains nevertheless some particles

of Cheese and Whey. The particles of Whey, being much the lightest,

endeavour, on the first application of heat, to extricate themselves

from amongst the particles of Butter, and to rise in distillation. Thus

they form the drops of acidulated phlegm which come over at first,

and, in struggling to get free, lift up the buttery parts, or actually

boil, which occasions the ebullition observable at the beginning of

the process. When they are once separated, the melted Butter remains

calm and smooth without boiling. If you want to make it boil you must

apply a much greater degree of heat; which you cannot do in close

vessels, without spoiling the whole operation: because the degree of

heat necessary for that purpose would force up the Butter in substance,

which would rush over into the receiver, without any decomposition.

Indeed if the vessels were luted they would be in danger of bursting.

As to the caseous parts, which are mixed with fresh Butter, they also

separate at the beginning of the distillation, when the Butter is

melted, and gather on its surface in a scum. These particles of Cheese

and Whey, which are heterogeneous to Butter, help to make it spoil the

sooner. And for this reason those who want to keep Butter a long time,

without the use of salt, melt it, and thereby evaporate the aqueous

parts. The lightest portion of the particles of Cheese rises to the

surface, and is skimmed off; the rest remains at the bottom of the

vessel, from which the Butter is easily separated, by decanting it

while it is yet fluid.

Butter may also be distilled, by incorporating it with some additament

which will yield no principle itself, nor retain any of those of the

Butter. I have distilled it in this manner with the additament of fine

sand: the operation succeeds very well, is sooner finished, and more

easily conducted: but I chose to describe here the manner of doing

it without additament; because the several changes, which the Butter

undergoes in the retort during the operation, may be better observed.

If you desire to convert the Butter wholly into Oil, you must take the

fixed matter you find in the receiver, and distil it once more, or

oftener, according to the degree of fluidity you want to give it. The

case is the same with this matter as with all other thick Oils, which,

the oftener they are distilled, grow always the more fluid, because in

every distillation they are separated from part of the Acid, to which

alone they owe their consistence.

PROCESS III.

_The Curd of Milk analyzed by distillation._

Into a glass retort put some new Curd, having first drained it

thoroughly of all its Whey, and even squeezed it in a linen cloth to

express all its moisture. Distil it as you did Butter. There will come

over at first an acidulated phlegm, smelling like Cheese or Whey. As

the distillation advances, the Acidity of this phlegm will increase.

When it begins to run but very slowly raise your fire. There will come

over a yellow Oil, somewhat empyreumatic. Continue the distillation,

still increasing the fire by degrees as occasion requires. The Oil and

acid Phlegm will continue to rise; the Phlegm growing gradually more

acid, and the Oil deeper coloured, and more empyreumatic. At last, when

the retort is almost red-hot, there comes off a second black Oil, of

the consistence of Turpentine, very empyreumatic, and so heavy as to

sink in water. In the retort will be left a considerable quantity of

charred matter.

_OBSERVATIONS._

Cheese-curd barely drained, till no more Whey will drip from it, is

not entirely freed thereof; and for this reason we directed it to

be pressed in a linen cloth, before it be put into the retort to be

distilled. Without this precaution, the remaining Whey would rise in a

considerable quantity on the first application of heat; and, instead of

analyzing the Curd only, we should at the same time analyze the Whey

also. This is to be understood of green Curd and new-made Cheese; for,

if it be suffered to grow old, it will at length dry of itself: but

then we should not obtain from it the same principles by distillation;

as it corrupts and begins to grow putrid after some time, especially if

it be not mixed with some seasoning to preserve it.

The first Phlegm that rises in this distillation, as in that of Butter,

is a portion of the Whey that was left in the Cheese, notwithstanding

its being well pressed. This Phlegm grows gradually more acid, being

the vehicle of the Acids of the Cheese, which are forced up along with

it by the fire.

The Acid obtained from this matter is less in quantity, and weaker,

than that of Butter: and accordingly the Oil distilled from Cheese

is not fixed like that of Butter. Yet it is remarkable that the last

empyreumatic Oil, which is as thick as Turpentine, is heavier than

water: a property which it probably derives from the quantity of Acid

it retains.

The quantity of charred matter, which remains in the retort after the

distillation of Cheese, is much greater than that left by Butter; which

proves that the former contains a much greater quantity of earth. These

coals are exceeding difficult to burn and reduce to ashes. I have kept

them red-hot, in the open air, and in a very strong fire, about six

hours, continually stirring them, in order to bring the under parts to

the surface, that they might be burnt, yet I could not consume them

entirely. They even deflagrated afterwards with Nitre, as if they

had not been burnt at all; and yet, during the whole time of their

calcination, there appeared constantly a small flame, like that of

charcoal, on the surface of the matter.

PROCESS IV.

_Whey analyzed._

Evaporate two or three quarts of Whey almost to dryness in a _balneum

mariæ_; and distil the extract, or residuum, in a retort set in a

reverberating furnace, with degrees of fire, according to the general

rule. At first some Phlegm will come over; then a lemon-coloured acid

Spirit; and afterwards a pretty thick Oil. There will remain in the

retort a charred matter, which being exposed to the air grows moist.

Lixiviate it with rain water, and evaporate the lixivium: it will yield

you crystals of Sea-salt. Dry the charred matter, and burn it in the

open air with a strong fire, till it be reduced into ashes. A lixivium

of these ashes will shew some tokens of a Fixed Alkali.

_OBSERVATIONS._

Milk, as was said before, separates naturally and spontaneously into

three sorts of substances, the analyses whereof being put together make

a complete analysis of this animal liquor. I know no Author that hath

delivered the analyses of Butter and Cheese; so that the processes

here given for analyzing these two substances are taken from the

experiments I thought proper to make, in order to obtain the necessary

lights in this matter. As for the analysis of Whey, it is taken from

one of Mr. Geoffroy's Memoirs, containing experiments on several animal

substances, which was published in 1732. It is there so particularly

and so well described, that it was needless for me to attempt it anew.

It will appear, on examining the three analyses of the substances

whereof Milk consists, that none of them yields a Volatile Alkali:

which I think very worthy of notice; as it is, I believe, the only

animal matter from which such a Salt cannot be obtained. It is true,

the milk of animals that feed on vegetables may be considered as an

intermediate liquor between vegetable and animal substances; as an

imperfect animal juice, which still retains much of the vegetable

nature: and we actually find that Milk almost always hath, at least in

part, the properties of those plants with which the animals that yield

it are fed. Yet, as it cannot be formed in the body of the animal,

without mixing with several of its juices that are entirely perfected,

and become purely animal, it must appear strange that the analysis

thereof should not afford the least vestige of that principle, which

all other animal matters yield in the greatest plenty.

I imagine the reason of this may be found in the use to which Milk is

destined. It is intended for the nourishment of animals of the same

species with those in whose bodies it is produced. Consequently it

ought as much as possible to resemble the juices of the food which is

proper for those animals. Now, as animals that live only on vegetables

could not be properly nourished by animal matters, for which nature

itself hath even given them an aversion, it is not surprising that the

Milk of such animals should be free from any mixture of such things as

are unsuitable to the young ones whom it is designed to nourish. There

is reason therefore to think that nature hath disposed the organs,

in which the secretion of Milk is performed, so as to separate it

entirely from all the animal juices first mixed with it: and this I

take to be the principal difference between Milk and Chyle; the latter

being necessarily blended with the saliva, the gastric and pancreatic

juices, the bile and lymph, of the animals in which it is formed. Hence

it may be concluded, that, if a quantity of Chyle could be collected

sufficient to enable us to analyze it, the analysis thereof would

differ from that of Milk, in this chiefly that it would yield a great

deal of Volatile Alkali, of which Milk, as hath been said, yields none

at all.

The same thing probably takes place in carnivorous animals. It is

certain that those animals chuse to eat the flesh of such others only

as feed upon vegetables; and that nothing but extreme hunger, and the

absolute want of more agreeable food, will force them to eat the flesh

of other carnivorous animals. Wolves, which greedily devour sheep,

goats, &c. seldom eat Foxes, Cats, Polecats, &c. though these animals

are not strong enough to resist them. Foxes, Cats, and Birds of prey,

that make such terrible havock among wild fowl, and other sorts of

game, do not devour one another. This being laid down, there is reason

to think that the Milk of carnivorous animals is something of the

nature of the flesh of those animals that feed on vegetables, and which

they chuse to eat, and not of the nature of their own flesh; as the

Milk of animals that feed on vegetables is analagous to the juice of

vegetables, and when analyzed yields no Volatile Alkali, though every

other part of their body does.

But whatever be the nature of Milk, and of whatever ingredients

it be formed, it always contains the three several substances

above-mentioned; namely, the fat, or Buttery part, properly so

called, the Cheesy, and the Serous part, the last of which we are

now examining. It is, properly speaking, the Phlegm of the Milk, and

consists almost entirely of water. For this reason it is proper to

lessen the quantity thereof considerably by evaporation, so that its

other principles, being concentrated and brought nearer together, may

become much more sensible. There is no danger of losing any essential

part of the Whey in the evaporation, if it be performed in the _balneum

mariæ_, with such a gentle heat as may carry off the aqueous parts

only: this greatly shortens the analysis, which will prove exceeding

long and tedious, if all the water be distilled off in close vessels.

As Whey is chiefly the aqueous part of Milk, as said above, it must

contain all the principles thereof that are soluble in water; that

is, its saline and saponaceous parts. And accordingly the analysis

thereof shews that it contains an Oil, rendered perfectly saponaceous

by an Acid; that is, made perfectly miscible with water. This quality

of the Oil contained in Whey appears from the perfect transparency of

that liquor, which we know is the mark of a complete dissolution. In

the distillation of Whey, the saponaceous matter contained therein is

decomposed; the saline part rises first, as being the lightest; this

is the Acid taken notice of in the process; after which the Oil, now

separated from the principle which rendered it miscible with water,

comes over in its natural form, and doth not afterwards mix with the

aqueous part.

Besides the saponaceous matter, Whey contains also another saline

substance; namely, Sea-Salt: this is obtained by lixiviating the _caput

mortuum_ left in the retort, which, because of its fixedness, cannot

rise with the other principles in distillation. To this Salt it is

owing that what remains in the retort after distillation grows moist in

the air; for we know that Sea-salt thoroughly dried hath this property.

The fixed Alkaline Salt, obtained from the _caput mortuum_ burnt to

ashes, proves that Milk still retains something of the vegetable

nature: for the following analysis will shew us that matters purely

animal yield none at all.

CHAP. II.

_Of the_ SUBSTANCES _which compose an_ ANIMAL BODY.

PROCESS I.

_Blood analyzed. Instanced in Bullock's Blood._

In a _balneum mariæ_ evaporate all the moisture of the Blood that the

heat of boiling water will carry off. There will remain an almost dry

matter. Put this dried Blood into a glass retort, and distil with

degrees of heat, till nothing more will come over, even when the retort

is quite red-hot, and ready to melt. A brownish phlegm will rise at

first: this will soon be impregnated with a little Volatile Alkali, and

then will come over a yellow Oil, a very pungent Volatile Spirit, a

volatile Salt in a concrete form, which will adhere to the sides of the

receiver; and, at last, a black Oil, as thick as pitch. There will be

left in the retort a charred matter, which being burnt yields no Fixed

Alkali.

_OBSERVATIONS._

Blood, which is carried by the circulation into all the parts of the

animal body, and furnishes the matter of all the secretions, must be

considered as a liquor consisting of almost all the fluids necessary to

the animal machine: so that the analysis thereof is a sort of general,

though imperfect, analysis of an animal.

Blood drawn from the body of an animal, and set by in a vessel,

coagulates as it grows cold; and sometime afterwards the _coagulum_

discharges a yellowish _Serum_ or lymph; and in the midst thereof

swims the red part, which continues curdled. These two substances,

when analyzed, yield nearly the same principles; and in that respect

seem to differ but little from each other. Though the Serum of Blood

be naturally in a fluid form, yet it hath also a great tendency to

coagulate, and a certain degree of heat applied to it, either by water,

or by a naked fire, will curdle it. Spirit of Wine mixed with this

liquor produces on it the same effect as heat.

Blood, while circulating in the body of a healthy animal, and when

newly taken from it, hath a mild taste, which discovers nothing like

either an Acid or an Alkali; nor doth it shew any sign of either

the one or the other in Chymical trials. When tasted with attention

it betrays something like a savour of Sea-salt; because it actually

contains a little thereof, which is found in the charred matter left in

the retort after distillation, when carefully examined.

We shewed that Milk also contains a little of this Salt. It enters the

bodies of animals with the food they eat, which contains more or less

thereof according to its nature. It plainly suffers no alteration by

undergoing the digestions, and passing through the strainers, of the

animal body. The case is the same with the other Neutral Salts which

have a Fixed Alkali for their basis: we find them unchanged in the

juices of animals into whose bodies they have been introduced. They

are incapable of combining, as Acids do, with the oily parts; and so

are dissolved by the aqueous fluids, of which nature makes use to free

herself from those Salts, and discharge them out of the body; as shall

be shewn when we come to speak of Urine and Sweat.

Blood, like all other animal matters, is, properly speaking,

susceptible of no fermentation but that of putrefaction. Yet it turns

somewhat sour before it putrefies. This small degree of acetous

fermentation is most sensible in flesh; and especially in the flesh of

young animals, such as calves, lambs, chickens, &c.

The quantity of pure water, which Blood, in its natural state,

contains, is very considerable, and makes almost seven eighths thereof.

If it be distilled, without being first dried, the operation will be

much longer; because it will be necessary to draw off all this insipid

phlegm with a gentle fire. There is no reason to apprehend that, by

drying Blood in open vessels as directed, any of its other principles

will be carried off with its Phlegm: for it contains no other substance

that is volatile enough to rise with the warmth of a _balneum mariæ_.

This may be proved by putting some undried Blood into a glass cucurbit,

fitting thereto a head and receiver, and distilling, in a _balneum

mariæ_, all that the heat of the bath, not exceeding the heat of

boiling water, will raise: for, when nothing more will come over, you

will find in the receiver an insipid phlegm only, scarce differing

from pure water, except in having a faint smell like that of Blood;

wherein it resembles all the phlegms that rise first in distillation,

which always retain something of the smell of the matters from which

they were drawn. That part of the Blood, which remains in the cucurbit

after this first distillation, being put into a retort, and distilled

with a stronger fire, yields exactly the same principles, and in the

same proportion, as Blood dried in open vessels in the _balneum mariæ_:

so that, if this Phlegm of Blood contain any principles, the quantity

thereof is so small as to be scarce perceptible.

The Volatile Alkali that rises with the Oil, when Blood is distilled

in a retort with a degree of heat greater than that of boiling water,

is either the production of the fire, or arises from the decomposition

of an Ammoniacal Salt, of which it made a part. For we shall see, when

we come to treat of this saline substance, that it is so extremely

volatile as to exceed, in that respect, almost all other bodies that

we know: and therefore if this Volatile Alkali pre-existed formally in

the Blood, uncombined with any other matter capable, in some measure,

of fixing it, it would rise at first almost spontaneously, or at least,

on the first application of the gentlest heat. We have an instance of

this in Blood, or any other animal matter, that is perfectly putrefied;

which containing a Volatile Alkali, either formed or extricated by

putrefaction, lets go this principle when distilled, even before

the first phlegm: and, for this reason, when putrefied Blood is to

be analyzed, it must by no means be dried, like fresh Blood, before

distillation; for all the Volatile Alkali would by that means be

dissipated and lost at once.

The Volatile Alkali obtained from Blood that hath not undergone

putrefaction, affords matter of some speculation. Indeed the separation

of this Salt from Blood requires a degree of heat, vastly greater than

that which is necessary to make it rise, when it is perfectly formed

and disentangled: and this gives room to think that it is the result

of a combination formed by the fire, during the distillation. But then

this same degree of heat neither separates nor forms any Volatile

Alkali in a great number of plants, or in milk, as hath been shewn. Yet

it cannot be supposed that the blood of animals, which feed only on

those plants or on milk, is any other than these very matters digested

and rendered perfectly animal substances: whence it must be concluded,

that, when vegetable substances are converted into animal substances,

they undergo such alterations as render them capable of yielding, when

analyzed, a principle that was not discoverable in them before. Now we

know that this same principle, that is, the Volatile Alkali, is the

product of putrefaction, or, which is the same thing, of the last

degree of fermentation: and this, I think, makes the opinion of those

more than probable, who believe that trituration and mechanical motion

are not the only causes, that effect the conversion of food into an

animal juice, but that fermentation hath a great share in this change.

It is true, we do not find, in animal matters, any manifest token of an

Ardent Spirit, an Acid, or a Volatile Alkali; nor, consequently, any

substance that is an evident production of any of the three different

degrees of fermentation: and yet, as substances perfectly animalized

are exactly in the same state with vegetables that have undergone the

first, and even the second, degree of fermentation, so that they are

susceptible of putrefaction only, (or, at least, if they shew at first

some faint tokens of acidity, they run immediately and rapidly into

complete putrefaction); it is nevertheless probable, that vegetable

matters, in order to their becoming animal substances, undergo certain

changes and alterations, which have some resemblance with those

produced by fermentation.

This opinion is further confirmed by two other analogies, between

animal matters, and vegetables advanced to the last stage of

fermentation; which is, that they yield neither an Essential Oil nor

a Fixed Alkali: for the coal, that remains in the retort after the

distillation of Blood, being burnt in an open fire, discovers no Fixed

Alkali in its ashes.

The want of a Fixed Alkali in animal matters arises from hence, that

their Acid is nearly in the same state with the Acid of vegetable

matters which have undergone putrefaction; that is, it is so subtilized

and attenuated, as to be fit to enter into the combination of a

Volatile Alkali, and is no longer so intimately united with the fixed

earth as to produce therewith a Fixed Alkali in the fire.

Though Blood and other animal matters afford no Fixed Alkali, but, on

the contrary, yield much Volatile Alkali, it doth not therefore follow

that all the Acid, which those substances contained before they were

analyzed, is employed in the production of a Volatile Alkali. We shall

hereafter take notice of an animal matter which contains a great deal

of Acid: and, not to depart from our present subject, it doth not

appear to me to be a settled point among Chymists, whether or no Blood,

when analyzed, yields a portion manifestly acid, and possessing all the

properties of an Acid.

Mr. Boerhaave, with some other Chymists, makes no mention of any

Acid in his analysis of Blood. Mr. Homberg, on the contrary, says[18]

expressly, that he constantly obtained an Acid from the Blood and

flesh of different sorts of animals, of which he analyzed a great

number. Mr. Boerhaave's authority is very respectable, and of great

weight: on the other hand, Mr. Homberg's experiments are very

conclusive, seem to be made with great care, and are all affirmative.

This apparent diversity in the same analysis, delivered by these two

great men, determined me to analyze Blood myself, and to examine

scrupulously all the principles I could obtain from it.

[18] Memoirs of the Academy of Sciences for 1712.

I therefore distilled some Bullock's Blood in a retort with degrees

of fire. Some Phlegm came over first, and then a Volatile Spirit. I

changed my receiver; and on increasing the fire there arose, with the

Volatile Spirit, a yellow Oil, a Volatile Salt in a concrete form, a

russet liquor which smelled strong of Volatile Alkali, and seemed at

first to be only a Spirit impregnated with much of that Salt: at last

came a very thick fetid Oil.

In this brown liquor, which comes off towards the end of the

distillation, Mr. Homberg affirms the Acid to be contained: but, as it

certainly is replete with a Volatile Alkali also, he alledges that it

contains, at the same time, both a Volatile Alkali and the animal Acid;

that these two Salts are distinct from each other, and not combined

together in the form of an Ammoniacal Salt; that each of consequence

possesses its peculiar properties; and that this liquor is at the same

time both Acid and Alkaline; that it effervesces with Acids, and also

changes the blue colours of plants to red.

The Alkaline quality of this liquor is very evident, and discovers

itself in every Chymical trial; but the same cannot be said of its

Acid property. I dropped some of it on blue paper, the colour of which

did not at first change in the least, nor acquire the faintest shade

of redness. This experiment almost determined me to conclude that Mr.

Homberg was mistaken: but some time afterwards I perceived that the

blue paper began to turn red where it had been wetted, and that the red

colour grew deeper and deeper as the paper dried: and this convinced

me, that this liquor actually contains an Acid, as Mr. Homberg

asserted; but, that the Volatile Alkali in this liquor, being much more

copious than the Acid, had first entered the paper, and hindered the

Acid from turning it red as usual; and that, as the Alkali evaporated,

the Acid began to act, and produce the customary effect. Hence we see

that the Acid of Blood, though extricated by distillation, is not

easily perceived at first, because of the great proportion of Volatile

Alkali, with which the liquor containing it is impregnated. This is

probably what prevented its being discovered by several Chymists, who,

it seems, did not suspect its existence, and therefore did not look for

it.

Mr. Homberg takes no notice of this little difficulty in his Memoir:

but he relates an experiment which might have given occasion to suspect

it. It is in his analysis of Human Blood. As the Acid in Human Blood is

in less quantity, and less perceptible, than in the Blood of animals

that live wholly on vegetables, he directs a second distillation of the

brown liquor, which contains at once both the Volatile Alkali and the

Acid, till very little thereof be left in the retort. _This residuum_,

says he, _contains a very perceptible and distinct Acid_. There is

reason to believe, from Mr. Homberg's directing the saline liquor

to be distilled again, that he did not find the Acid sufficiently

perceptible in it at first. Now a second distillation is a very good

way to render it much more sensible. For though this animal Acid be

volatile, the Volatile Alkali is still vastly more so; and therefore

if the liquor containing both these saline substances be distilled,

the Volatile Alkali must needs rise first, and leave the Acid alone,

or almost alone, at the bottom of the retort. This is exactly the case

in our experiment on blue paper; the operation being here performed

with a small quantity, and much more expeditiously, as appears from our

account of it.

It is not at all surprising that the Volatile Alkali and animal Acid,

though confounded in the same liquor, should not be united together and

converted into a Neutral Ammoniacal Salt. Mr. Homberg pretends that

these two saline matters do not act upon each other, because they are

too much dephlegmated. The oily parts, with which they are both loaded,

may also contribute thereto: nor is this unprecedented; the same thing

being observed of the Acid and the Volatile Alkali of several vegetable

substances.

Mr. Homberg, justly suspecting that there might be some difference

between the condition of the Acid in the Blood of animals that feed

altogether on vegetables, and that in the blood of those that feed only

on flesh, examined likewise, by decomposition, the Blood and the flesh

of some carnivorous animals. In these also he found an Acid; and it

doth not appear that he observed any great difference, in this respect,

between their Blood and that of other animals. The difference he found

between the Blood of young, and that of grown, or old, animals, with

respect to the Acid, seems, by his account, to be more considerable;

the Blood of the former containing much more of it than that of the

latter: and this is so much the more probable, as we know that the

flesh of young animals grows sour, before it putrefies, more sensibly

than that of old ones.

We shall conclude this head with a remark concerning the management

required in distilling Blood. When the operation is advanced to a

certain point, the matter contained in the retort often swells so as to

stop the neck of that vessel entirely, and by that means makes it burst

with an explosion. To avoid this inconvenience, a very small quantity

of Blood must be put into the retort, and the fire must be governed

very warily. I have also found that this accident may generally be

prevented by mixing the Blood with some matter that can afford no

principle by distillation; such as pounded glass or fine sand.

PROCESS II.

_Flesh analyzed. Instanced in Beef._

Into an alembic or retort, placed in a sand-bath, put some lean Beef,

from which you have carefully separated all the fat. Distil till

nothing more will rise. In this first distillation a phlegm will come

over, weighing at least half the mass of the distilled flesh. In the

retort you will find a matter almost dry, which you must afterwards

distil, with a naked fire, in a reverberating furnace, taking the usual

precautions. There will come over at first a little phlegm replete

with Volatile Alkali; then a Volatile Alkali in a dry form, which will

stick to the sides of the vessel; and also a thick Oil. After the

distillation there will be left in the retort a black, shining, light

coal. Burn it to ashes in the open air, and lixiviate those ashes: the

water of the lixivium will have no Alkaline property, but will shew

some tokens of its containing a little Sea-salt.

_OBSERVATIONS._

This analysis of Beef is taken from a Memoir given in by Mr. Geoffroy

in 1730, the purpose of which was a Chymical examination of the meat

commonly used to make broth. The flesh of an animal, as appears from

the process, yields much the same principles with its Blood: and it

cannot be otherwise; because it is formed all together of materials

furnished by the Blood.

Mr. Geoffroy observes, that the first phlegm, drawn off from it in

the _balneum mariæ_, produces a white precipitate in a solution of

Corrosive Sublimate; which shews it to contain a little Volatile

Alkali: but the quantity thereof must be very small; seeing the phlegm

that contains it smells only like broth, and not like a Volatile

Alkali; one particle of which, we know, is capable of affecting the

organ of smelling very sensibly. As to the Acid of flesh, there is

great reason to believe that it is conditioned exactly like that of

Blood.

The ashes of the _caput mortuum_ of flesh, burnt in an open fire,

attract the moisture of the air, as Mr. Geoffroy remarks, and increase

in weight, though they contain no Fixed Alkali. However, this is not at

all surprising; since they contain some Sea-salt, the known property

whereof is to grow moist in the air.

The flesh of animals contains much matter that is soluble in water. Mr.

Geoffroy examined separately that part of flesh which water is capable

of dissolving. With this view he boiled four ounces of beef with three

pints of water, in a very close vessel, and repeated the operation six

times with equal quantities of fresh water; in order to extract, as

far as possible, all the juices of the meat. These broths he put all

together, the last of them having but a faint smell of very weak veal

broth: he evaporated them over a slow fire, filtering them towards the

end of the evaporation, to separate an earthy part; and there remained

in the vessel a moderately solid extract, which soon grew moist in

the air. This extract, being analyzed, yielded a dram and two grains

of Volatile Salt, which adhered to the sides of the receiver; not in

ramifications, as Volatile Salts usually do, but in flat crystals,

mostly in the form of parallelopipeds. The Spirit and the Oil, which

came over together after the Volatile Salt, weighed thirty-eight

grains. Salt of Tartar being mixed with this Volatile Salt seemed to

increase its strength; which gives room to suspect that the latter

contains an Ammoniacal Salt.

The charred matter left in the retort weighed but six grains. Its

lixivium gave some tokens of Sea-salt, by making a white precipitate

in a solution of quick-silver. The mass of fleshy fibres, that was

exhausted by boiling, being dried and analyzed in the same manner,

yielded a Volatile Spirit, a Volatile Salt in a concrete form, which

stuck to the sides of the receiver in ramifications as usual; and a

thick fetid Oil. There now remained in the retort a charred matter,

which being burnt in the open air or not burnt, shewed not the least

sign of its containing any saline matter.

This method of analyzing flesh, by boiling it at first in water, in

order to extract all that can be dissolved by this menstruum, shews us

that animal flesh contains an Oil, which is in a saponaceous state:

for the extract made therefrom, by water, yields in distillation a

considerable quantity of Oil, which was perfectly dissolved in the

water, while that extract was in the diluted state of broth, and before

it was analyzed.

It is remarkable that the Volatile Salt, yielded by the extract of

flesh, is different from that which is obtained out of the flesh

itself, when nothing hath been extracted from it. This Salt, as Mr.

Geoffroy observed, differs from the common Volatile Alkalis in the form

of its crystals; which made that Chymist justly consider it as a Salt

of a somewhat Ammoniacal nature; a kind of Essential Salt of flesh.

There is reason to think that this Salt, when dissolved in the water

in which we boil flesh, is separated therefrom, by the action of

fire, with more ease than while it remains combined with the other

principles, in the substance of the flesh; that its separation, in

the latter case, requiring a greater degree of heat, it is thereby

decomposed; and that the Volatile Alkali, which is obtained from

flesh distilled in the usual manner, is only one of the parts that

constituted the Ammoniacal Salt thereby decomposed.

The charred matter remaining, after the distillation of flesh first

exhausted by boiling, yields nothing saline; because the Sea-salt,

which is the only Fixed Salt it could contain, was dissolved by the

water together with the matter of the extract.

Mr. Geoffroy likewise examined what parts of flesh Spirit of Wine

is capable of dissolving. For this purpose he took four ounces of

Beef, dried in the _balneum mariæ_, poured on it an equal weight of

well rectified Spirit of Wine, and left the whole in digestion for a

considerable time. The Spirit extracted from the Beef a weak tincture,

and separated from it some drops of Oil: it acquired a brown colour,

and a faint smell. Mr. Geoffroy found, by several experiments, that

the Spirit of Wine had taken up a portion of the Ammoniacal, or

Essential, Salt of the flesh. With respect to the Oil, if any at all

were dissolved, it could be but very little; for that which the Spirit

separated, and which retained its natural form, was certainly not

dissolved: seeing in that case it would not have been perceived, but

would have made a homogeneous liquor, to appearance, with the Spirit of

Wine.

PROCESS III.

_Bones analyzed. Instanced in Ox-bones._

Cut into pieces the Bones of a leg of beef, carefully separating all

the marrow. Put them into a retort, and distil them in a reverberating

furnace, as usual. A phlegm will come over first; then a Volatile

Spirit, which will become stronger and stronger; afterwards a Volatile

Salt in a dry form, with some Oil; and, lastly, a black Oil, with a

little more Volatile Salt. There will be left in the retort a charred

matter, from which a little Sea salt may be extracted. Reduce this

charred matter to ashes, by burning it in the open air. These ashes

will give some slight tokens of a Fixed Alkali.

_OBSERVATIONS._

The analysis of Bones proves that they consist of the same principles

with flesh and blood; and the same may be said, in general, of all

matters that are truly animal, or that actually constitute any part of

an animal.

Nevertheless, we find in the ashes of Bones somewhat of an Alkaline

quality; seeing they make a red precipitate in a solution of Corrosive

Sublimate: and yet a true Fixed Alkali cannot be obtained from them.

These ashes are probably in the same case with quick lime; which hath

certain properties of Alkaline Salts, though no Salt of that kind can

be extracted from it.

Mr. Geoffroy analyzed Bones in the same manner as he did flesh; that

is, he at first made a strong decoction of them with water, and

then examined and distilled apart the extract afforded him by that

decoction, and the Bones deprived of that extract. On this analysis he

made two remarkable observations.

The first is, that Bones yielded to boiling water their principles and

their Volatile Salts, both sooner and more copiously than flesh did:

for in the analysis which Mr. Geoffroy made of several sorts of flesh,

though he robbed them in a manner of all their principles by boiling,

yet their dried fibres afterwards yielded a considerable quantity of

Volatile Salt; whereas the Bones, of which he had made an extract by

boiling, afforded him but a very small quantity thereof when analyzed.

The second observation worthy of notice which Mr. Geoffroy made on

his analysis of Bones is this; the Salt, which, as was shewn in the

analysis of flesh, was resolved by the water wherein he boiled the

flesh, and consequently arose when he distilled the extract obtained

from that decoction, and crystallized in the form of parallelopipeds,

took a quite different turn in the analysis of Bones. None of it

appeared in distilling the extract made by decoction, but arose in

distilling the boiled Bones, that were exhausted of almost all their

other principles by the decoction with water. These differences

probably arise from the different contexture of the animal matters in

which they are observed.

This analysis of Bones may serve as a pattern for analyzing all the

solid parts of animals, such as horns, hoofs, ivory, &c.

PROCESS IV.

_Animal Fat analyzed. Instanced in Mutton-Suet._

Put as much Mutton-Suet as you please into a glass retort, only taking

care that the vessel be but half-full; and distil with degrees of fire

as usual. A phlegm smelling of the Suet will rise first, and soon grow

very acid. After this some drops of Oil will come over, and be followed

by a matter like Oil, in appearance, when it comes over; but it will

fix in the receiver, and acquire a consistence somewhat softer than

Suet. This kind of Butter of Suet will continue to rise to the end of

the distillation; and there will be left in the retort a small quantity

of charred matter.

_OBSERVATIONS._

Though animal Fat be a substance that hath passed through all the

strainers of the body; though it hath undergone all the elaborations

necessary to form an animal matter, and become itself part of the

animal: it contains, nevertheless, as its analysis shews, principles

differing greatly from those of all other animal matters: so that it

must be classed, in some sort, by itself.

It consists almost entirely of Oil: but this Oil is in a concrete

form, and observes the general rule of all concreted oily matters,

which owe their consistence wholly to the Acid that is combined with

them. The rule is evidently so general, that it extends even to the

animal kingdom, where, in all other instances, Acids seem to be almost

annihilated.

All we said above on the subject of Butter must be applied here: for

animal Fat, properly so called, and Butter, do not, in my opinion,

differ sensibly from each other, with respect to their analysis. And

therefore there is great reason to believe, that what is Butter in

Chyle, or Milk, becomes Fat when fixed in the animal body. It is a

kind of repository, in which nature lays up and confines the Acid that

is unnecessary to the animal composition, and which she could not any

other way eliminate.

I made choice of Mutton-Suet for an instance of the analysis of Fat;

because this Fat, being the firmest of any, must contain a stronger and

more perceptible Acid.

When it is thus distilled, the part which remains fixed hath much less

consistence than the Suet had before; which arises from its having lost

part of its Acid. Repeated distillations will deprive it of a much

greater quantity thereof, and so reduce it into an Oil that will always

remain clear and fluid.

Not one particle of Volatile Alkali is obtained by distilling Suet:

but then the experiment will not succeed as it ought, unless care

be taken to free the Suet perfectly from all the membranes, and all

the particles of flesh and blood that may be mixed with it; for, if

it should be distilled without this precaution, those heterogeneous

matters mingled with it would yield a great deal of Volatile Alkali in

distillation; which might impose on the Artist, and make him think the

Salt came actually from the Suet. Suet that hath been often melted, as

the tallow, for instance, of which candles are made, is sufficiently

purified: of this I made use in my analysis, and it yielded me no

Volatile Alkali; at least I could perceive none.

In conclusion, all that hath been said, on several occasions, touching

the properties of concreted oily matters, may be applied to Suet. I

shall only observe here, that it is one of those that manifest no

Acidity, and consequently that in its natural state it is not soluble

in Spirit of Wine, and only becomes soluble in that menstruum by

degrees, as its Acid is extricated by repeated distillations: and on

this account it ought to be classed with Bees-Wax, and other oily

compounds of that kind.

PROCESS V.

_Eggs analyzed. Instanced in Pullet's Eggs._

Put some Hen's Eggs in water, and boil them till they be hard. Then

separate the Yelks from the Whites. Cut the Whites into little bits;

put them into a glass cucurbit; fit on a head and receiver; distil in

a _balneum mariæ_ with degrees of fire, raising it towards the end

to the strongest heat which that bath can give; that is, to the heat

of boiling water. There will come over an aqueous liquor, or insipid

phlegm; the quantity whereof will be very considerable, seeing it will

make about nine-tenths of the whole mass of the Whites of the Eggs.

Continue your distillation, and keep the water in the bath constantly

boiling, till not a drop more of liquor will ascend from the alembic.

Then unlute your vessels. In the cucurbit you will find your Whites of

Eggs considerably shrunk in their bulk. They will look like little bits

of brown glass, and be hard and brittle.

Put this residuum into a glass retort, and distil, as usual, in a

reverberating furnace with degrees of heat. There will come over a

Volatile Oily Spirit, a yellow Oil, a Volatile Salt in a dry form, and,

at last, a black thick Oil. There will be left in the retort a charred

matter.

Reduce also into the smallest pieces you can the hard Yelks of the

Eggs which you separated from the Whites. Set them in a pan over a

gentle fire: stir them with a stick till they turn a little brown, and

discharge a substance like melted marrow. Then put them into a new

strong canvass bag, and press them between two iron plates well heated;

whereby you will obtain a considerable quantity of a yellow Oil.

Let what remains in the bag be distilled in a retort set in a

reverberating furnace: it will give you the same principles as you got

from the Whites.

_OBSERVATIONS._

Of the two perfectly distinct substances that constitute the Egg, the

Yelk contains the embryo of the chick, and is destined to hatch it:

the White is to serve for the nourishment of the chick when it is

formed.

These two matters, though they contain the very same principles, yet

differ considerably from each other; and chiefly in this, that their

principles are not in the same proportions.

The White of an Egg contains so much phlegm, that it seems to consist

almost totally thereof. All the aqueous liquor, obtained by distilling

it in the _balneum mariæ_, is, properly speaking, nothing but pure

water; for no Chymical trial can discover in it either an Acid or a

Volatile Alkali; or any very perceptible Oily part. And yet it must

contain some Oil, because the liquor that rises last is a little

bitterish to the taste, and smells somewhat of empyreuma. But the

principles from which it derives these properties are in too small

quantities to be distinctly perceived.

If, instead of distilling the hard White of an Egg, with a view

to draw off the great quantity of water it contains, you leave it

some time in an air that is not too dry, the greatest part of its

moisture separates spontaneously, and becomes very sensible. In all

probability this is the effect of a beginning putrefaction, which

attenuates this substance, and breaks its contexture. The liquor thus

discharged by the White of an Egg thoroughly dissolves Gum-Resins, and

particularly Myrrh. If you desire to dissolve Myrrh in this manner,

cut a hard-boiled Egg in halves; take out the Yelk; put the powdered

Gum-Resin into the cavity left by the Yelk; join the two halves of

the White; fasten them together with a thread, and hang them up in a

cellar. In a few days time the Myrrh will be dissolved by the moisture

that issues from the White of the Egg, and will drop into the vessel

placed underneath to receive it. This liquor is improperly called _Oil

of Myrrh per deliquium_.

All the properties of the Whites of Eggs, as well as the principles

obtained by analyzing them, are the same with those of the lymphatic

part of the blood; so that there is a great resemblance between these

two substances.

As to the Yelk, it is plain from its analysis that Oil is the

predominant principle thereof. If the Yelk of an Egg be mixed with

water, the Oil with which it is replete, and which is by nature very

minutely divided, diffuses itself through the whole liquor, and remains

suspended therein by means of its viscosity. The liquor at the same

time becomes milk-white like an emulsion, and is in fact a true animal

emulsion.

In order to obtain the Oil of Eggs by expression with the more ease,

care must be taken to chuse Eggs that are seven or eight days old;

because they are then a little less viscous. Nevertheless, their

viscosity is still so great that they will not easily yield their

Oil by expression: and therefore, in order to attenuate and destroy

entirely this viscosity, they must be torrefied before they are put to

be pressed.

The Oil of Eggs, like all other oily animal matter, seems analagous

to the Fat Oils of vegetables. It hath all the properties that

characterise those Oils. Its colour is yellow, and it smells and tastes

a little of the empyreuma, occasioned by torrefying the Yelks. It is

rendered somewhat less disagreeable by being exposed to the dew for

thirty or forty nights, if care be taken to stir it often in the mean

time.

To conclude: all the principles, both in the Yelk and the White of an

Egg, are the same as those found in Blood, Flesh, and all other matters

that are perfectly animal.

CHAP. III.

_Of the_ EXCREMENTS _of_ ANIMALS.

PROCESS I.

_Dung analyzed. Instanced in Human Excrement. Mr. Homberg's Phosphorus._

Take any quantity you please of human Excrement, and distil it in a

glass alembic set in the _balneum mariæ_. You will obtain an aqueous,

clear, insipid liquor; which will nevertheless have a disagreeable

odour. Having urged the distillation as far as is possible, with the

heat of this bath, unlute your vessels, and you will find at the bottom

of the cucurbit a dry matter, making about an eighth part only of what

you put into it. Put this residuum into a glass retort, and distil in a

reverberating furnace, with degrees of heat. You will obtain a Volatile

Spirit, and a Volatile Salt, with a fetid Oil; and a charred matter

will be left in the retort.

_OBSERVATIONS._

Mr. Homberg made a great many experiments on the dung of animals;

concerning which he composed two Memoirs published in the Academy's

collection for 1711. That Chymist tells us, that, in distilling

Excrement, he aimed not so much at discovering the principles of which

it consists, as he was desirous to satisfy a friend of his, who had

earnestly entreated him to try whether he could not extract therefrom

a clear Oil, having no bad smell; because he had seen, as he said,

Mercury fixed into pure Silver by such an Oil.

Mr. Homberg's labour had the usual fate of all enterprises of this

nature. He actually found the art of drawing from Excrement a

clear scentless Oil; but, in whatever way he applied it to Mercury,

it produced no change in that metallic substance. However, as Mr.

Homberg was a man of sagacity, and knew how to improve every hint

offered by his experiments, he made several curious discoveries on this

occasion; of which we shall give a concise account, after we have made

some remarks on the principles obtained from Excrement by the method

described in the process.

This substance, consisting of matters subject to putrefaction, hath

constantly a fetid smell, like that of all putrid matters; having been

for some time confined in a warm, moist place, which we know promotes

putrefaction, and even quickly produces it. Yet the analysis thereof

proves that it is not putrefied, or at least not entirely so: for

all putrefied matters contain a Volatile Alkali perfectly formed and

extricated; and, as this principle rises with less heat than that of

boiling water, it always comes over first in distillation. Now we have

seen that, with the heat of boiling water, it parts with nothing but an

insipid phlegm, containing no Volatile Alkali: a sure proof that the

fecal matter is not completely putrefied.

There is nothing remarkable in the Volatile Salt and fetid Oil, which

rise with a degree of heat greater than that of boiling water. They are

common productions, of which we have made frequent mention in several

of the preceding analyses; and therefore they need not now detain

us from proceeding to give a summary account of Mr. Homberg's chief

discoveries.

One of the methods by which Mr. Homberg endeavoured to obtain from

Excrement a clear Oil, without any bad smell, was to separate its

earthy and gross parts, by filtering it before he distilled it. "For

this purpose he diluted Excrement newly discharged with hot water,

using a quart of water to an ounce of feces. Then he let the mixture

stand to cool, and, the gross parts falling to the bottom, he poured

off the water by inclination. This liquor he filtered through brown

paper, and evaporated to a pellicle over a gentle fire. There shot

in it long crystals of four, five, and six sides, which Mr. Homberg

thinks may be called the Essential Salt of Excrement. They resemble

Salt-petre, in some measure, and deflagrate in the fire much like it;

with this difference, that their flame is red, and they burn slowly;

whereas the flame of Salt-petre is white and very vivid: probably, says

Mr. Homberg, because there is too much of an oily matter in the one,

and less in the other.

"Mr. Homberg distilled this Salt in a glass retort with degrees of

fire, and at last with a very violent one. At first there came over an

aqueous liquor, sharp and acid, which was followed by a brown fetid

oil, smelling very strong of empyreuma. This distillation he attempted

four several times; and each time the matter in the retort took fire,

just when the Oil began to come off."

The Salt which Mr. Homberg obtained from excrement is very remarkable.

We shall have occasion to speak of it in another place, and shall only

observe here, that its Nitrous character is by no means ambiguous:

its deflagrating on live coals convinced Mr. Homberg of its being a

true Nitre. But its constantly taking fire in the retort, as oft as

distilled, is a sure proof that it is a Nitrous Salt: for Nitre only

hath the property of thus taking fire in close vessels, and making

other combustible matters burn along with it.

The process by which Mr. Homberg at last obtained from Excrement a

clear oil without any bad smell is curious, and worthy of a place here;

on account of the views and occasions of reflection which it may open.

"Mr. Homberg having tried in vain, by distilling Excrement a great many

different ways, to obtain from it such an Oil as he wanted, resolved to

employ fermentation, the effect whereof is to change the disposition

of the principles of mixts. With this view he dried some Excrement in

the water-bath, and, having pulverized it, poured thereon six times its

weight of phlegm that had been separated from it by distillation, and

put the whole into a large glass cucurbit, covered with an inverted

vessel that fitted exactly into it, and was close luted. This vessel he

set in a _balneum mariæ_ for six weeks, keeping up such a gentle heat

as would not burn one's hand; after which he uncovered the cucurbit,

and having fitted thereto a head and a receiver, distilled off all the

aqueous moisture in the _balneum mariæ_ with a very gentle heat. It had

now lost almost all its bad smell, which was changed into a faint one.

It came over somewhat turbid, whereas it was very clear when put into

the cucurbit. Mr. Homberg found this water to have a cosmetic virtue:

He gave some of it to persons whose complexion, neck, and arms, were

quite spoiled, being turned brown, dry, rough, and like a goose skin:

they washed with it once a day, and, by continuing the use of this

water, their skin became very soft and white."

The dry matter, that remained in the bottom of the cucurbit after

distillation, had lost about a twentieth part of its weight; that is,

of twenty ounces, put at one time into the cucurbit, somewhat less than

nineteen ounces remained. Mr. Homberg suspects that it was not so dry

when put into the cucurbit as when it was taken out. Perhaps also the

species of fermentation which the matter underwent had attenuated and

volatilized some part of it; so that it came over with the phlegm in

distillation. The turbidness of that phlegm, which was clear and limpid

before, seems to countenance this conjecture.

"The dry matter left in the cucurbit after the first distillation, had

not the least smell of feces: on the contrary, it had an agreeable

aromatic odour; and the vessel in which Mr. Homberg had digested it,

being left open in a corner of his laboratory, acquired in time a

strong smell of Ambergris. It is surprising, as Mr. Homberg justly

observes, that digestion alone should change the abominable smell of

Excrement into an odour as agreeable as that of Ambergris.

"This dry matter he powdered coarsely, and put two ounces thereof at

once into a glass retort, that would hold about a pound or a pound

and half of water. This he distilled in a sand-bath with a very

gentle heat. A small quantity of an aqueous liquor came over first,

and then an Oil as colourless as spring-water. Mr. Homberg continued

the same gentle degree of heat, till the drops began to come off a

little reddish; and then he changed the receiver, stopping that which

contained the clear Oil very close with a cork. Having carried on

the distillation with a fire gradually augmented, there came over a

considerable quantity of red Oil; and there remained in the retort a

charred matter which burnt very readily."

The clear Oil, without any ill smell, which Mr. Homberg obtained from

the fecal matter by this process, was the very thing he was in search

of, and which he had been assured would convert Mercury into fine fixed

Silver: yet he ingenuously owns, that, whatever way he applied it, he

could never produce any change in that metallic substance. We shall now

proceed to the other discoveries made by Mr. Homberg on this occasion.

In his attempt to obtain a clear Oil from Excrement, he distilled it

with different additaments, and amongst the rest with Vitriol and Alum.

He found that the matters left in the retort, when he made use of these

Salts, being exposed to the open air, took fire of themselves; that

they kindled combustible matters; in a word, that they were a true

Phosphorus, of a species different from all then known. Pursuing these

first hints, he sought and found the means of preparing this Phosphorus

by a way much more expeditious, certain, and easy. His process is this.

"Take four ounces of Feces newly excreted: Mix therewith an equal

weight of Roch-Alum coarsely powdered: put the whole into a little iron

pan that will hold about a quart of water, and set it over a gentle

fire under a chimney. The mixture will melt, and become as liquid as

water. Let it boil with a gentle fire, constantly stirring it; breaking

it into little crumbs, and scraping off with a spatula whatever sticks

to the bottom or sides of the pan, till it be perfectly dry. The pan

must from time to time be removed from the fire, that it may not grow

red-hot, and the matter must be stirred, even while it is off the fire,

to prevent too much of it from sticking to the pan. When the matter is

perfectly dried, and in little clots, let it cool, and powder it in a

metal mortar. Then put it again into the pan, set it over the fire,

and stir it continually. It will again grow a little moist, and adhere

together in clots, which must be continually bruised and roasted till

they be perfectly dry; after which they must be suffered to cool, and

then be pulverized. This powder must be returned a third time to the

pan, set on the fire, roasted and perfectly dried: after which it must

be reduced to a fine powder, and kept in a paper in a dry place. This

is the first or preparatory operation.

"Take two or three drams of this powder. Put it into a little matrass,

the belly of which will hold an ounce or an ounce and half of water,

and having a neck about six or seven inches long. Order it so that your

powder shall take up no more than about a third part of the matrass.

Stop the neck of the matrass slightly with paper: then take a crucible

four or five inches deep: in the bottom of the crucible put three

or four spoonfuls of sand: set the matrass on this sand, and in the

middle of the crucible, so as not to touch its sides. Then fill up

the crucible with sand, so that the belly of the matrass may be quite

buried therein. This done, place your crucible, with the matrass, in

the midst of a little earthen furnace, commonly called a _Stove_, about

eight or ten inches wide above, and six inches deep from the mouth to

the grate. Round the crucible put lighted coals about half way up, and

when it hath stood thus half an hour, fill up with coals to the very

top of the crucible. Keep up this fire a full half-hour longer, or till

you see the inside of the matrass begin to be red. Then increase your

fire, by raising your coals above the crucible. Continue this strong

heat for a full hour, and then let the fire go out.

"At the beginning of this operation dense fumes will rise out of the

matrass, through the stopple of paper. These fumes issue sometimes in

such abundance as to push out the stopple; which you must then replace,

and slacken the fire. The fumes cease when the inside of the matrass

begins to grow red; and then you may increase the fire without any fear

of spoiling your operation.

"When the crucible is so cold that it may be safely taken out of the

furnace with one's hand, you must gradually draw the matrass out of the

sand, that it may cool slowly, and then stop it close with a cork.

"If the matter at the bottom of the matrass appear to be in powder when

shaken, it is a sign the operation hath succeeded: but if it be in a

cake, and doth not fall into powder on shaking the matrass, it shews

that your matter was not sufficiently roasted and dried in the iron

pan, during the preparatory operation."

Since Mr. Homberg, Mr. Lemeri the younger hath made a great many

experiments on this Phosphorus, which may be seen in the Memoirs

of the Academy for 1714 and 1715. In those Memoirs Mr. Lemeri hath

shewn, that Excrement is not the only matter capable of producing this

Phosphorus with Alum; but that, on the contrary, almost all animal and

even vegetable matters are fit for this combination; that though Mr.

Homberg mixed Alum in equal quantities only with the fecal matter, it

may be used in a much greater proportion, and, in certain cases, will

succeed the better; that, according to the nature of the substances to

be worked on, the quantity of that Salt may be more or less increased;

and that whatever is added, more than the dose requisite for each

matter, serves only to lessen the virtue of the Phosphorus, or even

destroys it entirely: that the degree of fire applied must be different

according to the nature of those matters; and, lastly, that Salts

containing exactly the same Acid with that of Alum, or the Acid of

those Salts separated from its basis and reduced into Spirit, do not

answer in the present operation: which shews, says Mr. Lemeri, that

many sulphureous matters may be substituted for Excrement in this

operation; but that there are no Salts, or very few if any, that will

succeed in the place of Alum. Nevertheless, a Chymist, who lately

communicated to the Academy a great number of experiments on this

Phosphorus, found that any Salt containing the Vitriolic Acid may be

substituted for Alum.

This Phosphorus, made either by Mr. Homberg's or by Mr. Lemeri's

method, shines both by day and by night. Besides emitting light,

it takes fire soon after it is exposed to the air, and kindles all

combustible matters with which it comes in contact; and this without

being rubbed or heated.

Mess. Homberg and Lemeri have given the most probable and the most

natural explanation of the cause of the accension and other phenomena

of this Phosphorus. What they say amounts in short to what follows.

Alum is known to be a Neutral Salt, consisting of the Vitriolic Acid

and a calcareous earth. When this Salt is calcined with the fecal

matter, or other substances abounding in Oil, the volatile principles

of these substances, such as their Phlegm, their Salts, and their

Oils, exhale in the same manner as if they were distilled; and there

is nothing left in the matrass, when those principles are dissipated,

but a charred matter, like that which is found in retorts wherein such

mixts have been decomposed by distillation.

This remainder therefore is nothing but a mixture of Alum and charcoal.

Now, as the Acid of this Salt, which is the Vitriolic, hath a greater

affinity with the phlogiston than with any other substance, it will

quit its basis to unite with the phlogiston of the coal, and be

converted by that union into a Sulphur. And this is the very case;

of which we have certain proofs in the operation for preparing this

Phosphorus: for when, after the volatile principles of the oily matter

are drawn off, the fire is increased, in order to combine closely

together the fixed parts that remain in the matrass, that is, the Alum

and the charred matter, we perceive at the mouth of the matrass a

small blue sulphureous flame, and a pungent smell of burning Sulphur.

Nay, when the operation is finished, we find a real Sulphur sticking

in the neck of the matrass; and, while the Phosphorus is burning,

it hath plainly a strong sulphureous smell. It is therefore certain

that this Phosphorus contains an actual Sulphur; that is, a matter

disposed to take fire with the greatest ease. But though Sulphur be

very inflammable, it never takes fire of itself, without being either

in contact with some matter that is actually ignited, or else being

exposed to a considerable degree of heat. Let us then see what may

be the cause of its accension, when it is a constituent part of this

Phosphorus.

We mentioned just now that the Acid of the Alum quits its basis, in

order to form a Sulphur by combining with the Phlogiston of the coal.

This basis we know to be an earth capable of being converted into Lime;

and that it is actually converted into Quick-lime by the calcination

necessary to produce the Phosphorus. We know that new-made Lime

hath the property of uniting with water so readily, that it thereby

contracts a very great degree of heat. Now when this Phosphorus,

which is partly constituted of the basis of the Alum converted into

Quick-lime, is exposed to the air, the Lime instantly attracts the

moisture of which the air is always full, and by this means, probably,

grows so hot as to fire the Sulphur with which it is mixed. Perhaps

also the Acid of the Alum is not totally changed into Sulphur; some

part thereof may be only half disengaged from its basis, and in that

condition be capable of attracting strongly the humidity of the air,

of growing very hot likewise by imbibing the moisture, and so of

contributing to the accension of the Phosphorus.

There is also room to think that all the Phlogiston of the charred

matter is not employed in the production of Sulphur in this Phosphorus,

but that some part of it remains in the state of a true coal. The black

colour of the unkindled Phosphorus, and the red sparkles it emits while

burning, sufficiently prove this. The explanation of the accension of

this Phosphorus, as here given by Mess. Homberg and Lemeri, is very

ingenious, and in the main just; but yet, in my opinion, the subject

deserves a more thorough examination.

PROCESS II.

_Human Urine analyzed._

Put some Human Urine into a glass Alembic; set it in a water-bath,

and distil till there remain only about a fortieth part of what you

put in; or else evaporate the Urine, in a pan set in the _balneum

mariæ_, till it be reduced to the same quantity. With this heat nothing

will exhale but an insipid Phlegm, smelling however like Urine. The

residuum will, as the evaporation advances, become of a darker and

darker russet, and at last acquire an almost black colour. Mingle this

residuum with thrice its weight of sand, and distil it in a retort set

in a reverberating furnace, with the usual precautions. At first there

will come over a little more insipid Phlegm like the former. When the

matter is almost dry, a Volatile Spirit will rise. After this Spirit,

white vapours will appear on increasing the fire; a yellow oily liquor

will come off, trickling down in veins; and together with this liquor a

concrete Volatile Salt, which will stick to the sides of the receiver.

At last there will come over a deep-coloured fetid Oil. In the retort

there will remain a saline earthy residuum, which being lixiviated will

yield some Sea-salt.

_OBSERVATIONS._

Urine must be considered as an aqueous liquor replete with all the

saline matters which are of no use to the body, either for nourishment

or health: it is a lixivium of animal matters, prepared by nature for

dissolving and separating from them all the unnecessary Salts. It

contains a very large quantity of almost pure phlegm, which evaporates

with the heat of a water-bath.

The residue of the Urine, from which this phlegm is separated by the

first distillation, though thereby rendered considerably thicker, doth

not coagulate, or curdle in the least, like Milk or Blood; which shews

that it contains no parts analagous to those of these two nutritious

liquors. Yet it contains oily and saline parts, disposed like those

of truly animal matters; as appears from the Spirit, the Volatile

Salt, and the Oil, obtained from it by distillation; which are, in

every respect, perfectly like the same principles yielded by other

animal substances. But, if the animal that made the Urine took in

with its food any of the Neutral Salts, which cannot be decompounded

by digestion; that is, of those chiefly which consist of Acids and

Alkalis, the Urine will contain, over and above the other parts of

that animal, almost all the Neutral Salt that entered into its body.

Accordingly human Urine is replete with a considerable quantity of

Sea-salt, because men eat a great deal of it. It is found, after the

distillation of the Urine, united with the _caput mortuum_ left in the

retort; because, being of a fixed nature, it doth not rise with the

volatile principles in distillation.

Besides this Sea-salt, Urine contains another Salt of a singular

nature, which crystallizes differently from Sea-salt. In this Salt,

according to Mr. Marggraff's experiments mentioned on the subject of

Phosphorus, is contained the Acid necessary to produce the Phosphorus

of Urine. There is reason to think that this Salt is a Sea-salt,

disguised by the fat matters with which it combines during its stay in

the animal body.

Mr. Boerhaave calls it the Essential Salt of Urine. If you desire to

have it by itself, you must evaporate the Urine, with a gentle heat,

to the consistence of fresh cream, filter it, and let it stand quiet

in a cool place. Crystals will at length shoot therein, and adhere

to the sides of the vessel. These crystals are the Salt you want:

they are brown and oily. If you desire to have them purer, you must

dissolve them in warm water, filter the solution, and set it by to

shoot. This operation repeated several times will render them clear and

transparent. Mr. Schlosser, a young and very promising Chymist, is the

last who hath made any experiments on this curious Salt of Urine. Those

who are desirous of a particular account of its properties may consult

his dissertation, printed at Leyden in 1753, as well as Mr. Marggraff's

excellent Memoirs, printed among those of the Academy of Berlin.

The chief result of Mr. Schlosser's experiments is, first, that this

Salt may be obtained from recent Urine, and even in greater quantities

than from putrid Urine, and that too in very little time: seeing it

crystallizes in twenty-four hours, after due evaporation.

Secondly, that this Salt is a Neutral Ammoniacal Salt, consisting of a

Volatile Alkali, (which can never be extracted from it but in a liquid

form, like that which is separated from Urine by the addition of Lime);

and of an Acid of a very singular nature, the most remarkable property

of which is, its being so fixed as to resist the violence of fire,

and turn into a sort of glass rather than exhale in vapours. This is

that Acid which, according to Mr. Marggraff's experiments, forms the

combination of Phosphorus when united with the Phlogiston. The other

properties of this singular Acid are the principal objects of Mr.

Marggraff's inquiries.

It follows, in the third place, from Mr. Schlosser's experiments, that

this Acid, being combined to the point of saturation with a common

Volatile Alkali, forms a true, regenerated Salt of Urine; and that, by

this union, the nature of the Volatile Alkali is so changed, that it

cannot afterwards appear by itself in a concrete form, but is always

fluid, like that which is extricated by the additament of lime.

If Fixed Alkalis be mixed with fresh Urine, they immediately separate

from it a Volatile Alkali; and, if the mixture be quickly put into

an alembic, and distilled, the first liquor that rises is a Volatile

Spirit: or else a Volatile Alkali in a concrete form will rise first,

provided the Fixed Alkali made use of be not liquid, and the Urine be

dephlegmated.

Herein Urine resembles other animal matters: for Fixed Alkalis produce

the same effect on them. This affords us good grounds for believing

that all animal matters contain a Neutral Salt of an Ammoniacal nature,

which the Fixed Alkali decomposes, as it doth all other Ammoniacal

Salts. Quick-lime also extricates from Urine a Volatile Alkali,

still more quick and pungent than that which is separated by a Fixed

Alkali, and which constantly remains liquid without ever putting on

a concrete form: and this is another proof of the existence of the

Ammoniacal Salt above-mentioned; for quick-lime hath just the same

effect on Sal-Ammoniac, as we shall see in its place. Mr. Schlosser's

experiments, compared with those now mentioned, seem to shew that the

Urine contains several distinct sorts of Ammoniacal Salts.

Of all the liquors which animals afford, Urine putrefies the most

easily, and by putrefaction parts with, or forms, the greatest quantity

of Volatile Alkali. If it be distilled when putrefied, there comes

over first a Spirit impregnated with much Volatile Alkali; then an

aqueous liquor, which Van Helmont assures us is a medicine of wonderful

efficacy in dissolving the stone in the bladder. When all this water is

come over, and the remaining matter is almost dry, there ascends, on

increasing the fire, a yellow Oil, together with a Volatile Salt.

After this there remains in the retort a black charred earthy matter,

containing a great deal of Sea-salt. If this matter be calcined in

the open air, in order to consume its Phlogiston, and be afterwards

lixiviated, all the Sea-salt it contains may by this means be easily

separated; nothing but its earth being left behind. This _caput

mortuum_ contains also the materials proper for forming Kunckel's

Phosphorus; and if, instead of calcining it in the open air, it

be urged with a violent fire, in close vessels, it will yield a

Phosphorus: but then all the precautions recommended on the subject of

Phosphorus must be used; and, in particular, the _caput mortuum_ must

be lixiviated before it be distilled, in order to free it from part of

the Sea-salt contained therein; because too much of that Salt might

defeat the operator, by not only melting itself, but melting also the

containing vessel during the operation.

CHAP. IV.

_Of the_ VOLATILE ALKALI.

PROCESS I.

_Volatile Alkalis rectified and depurated._

Mix together the Spirit, the Volatile Salt, the Phlegm, and the Oil,

obtained from any substance whatever. Put the whole into a large

wide-mouthed glass body, and thereto fit a head with a large beak. Set

this alembic in a water-bath, lute on a receiver, and distil with a

very gentle heat. There will ascend a Spirit, strongly impregnated with

a Volatile Alkali, and a Volatile Salt in a concrete form, which must

be kept by itself. Then increase your heat to the degree of boiling

water; whereupon there will rise a second Volatile Spirit, somewhat

more ponderous than the former, with a light Oil that will swim on its

surface, and a little concrete Volatile Salt. Proceed till nothing more

will rise with this degree of heat. Keep by itself what came over into

the receiver. At the bottom of the cucurbit you will find a thick fetid

Oil.

Into such another distilling vessel put the Spirit and Salt that rose

first in this distillation, and distil them in the _balneum mariæ_ with

a heat still gentler than before. A whiter, purer, Volatile Salt will

sublime. Continue the distillation till an aqueous moisture rise, which

will begin to dissolve the Salt. At the bottom of the vessel will be

left a phlegm, with a little Oil floating on it. Keep your Salt in a

bottle well stopped.

_OBSERVATIONS_.

In the analysis of any substance that yields a Volatile Alkali, this

Salt is generally found in the receiver, blended with the other

principles of the mixt; which, ascending from the retort in the form

of liquors and vapours, dissolve the Salt, or at least moisten it, and

render it very impure. So that, if you desire to have it without any

mixture, recourse must be had to a second distillation, in order to

separate it from the heterogeneous matters with which it is confounded.

It is of consequence in this distillation to apply but a very weak

degree of heat; because on that depends the success of the operation,

insomuch that, the less heat you employ to sublime the Salt, the

purer it will be. For, being far more volatile than any of the other

principles with which it is mixed, it must evidently rise by itself, if

no more heat be applied than is just necessary to elevate it; such a

heat being much too weak to raise the Oil and phlegm with which it is

blended.

Nevertheless, whatever care be taken to govern the heat, it is not

possible to hinder this Volatile Salt from carrying up some portions

of the principles mixed with it; those, to wit, with which it is most

closely united, and to which it hath by that means communicated a share

of its volatility. For this reason it requires a second rectification,

which is performed in the same manner as the former. But, seeing it is

more volatile and lighter after the first rectification than before,

being thereby freed from part of the heterogeneous matters with which

it was loaded, a still less degree of heat must be applied in this

second rectification.

The Oil with which the Volatile Salt is loaded, when but once

distilled, is perceivable only by the yellow colour and weight it

communicates thereto; because it is closely united therewith, and in

a perfectly saponaceous state. This appears from the facility with

which Volatile Salts, even the most oily, dissolve in water, without

discovering in the solution any separation of the oily parts, and even

without giving it a milky colour. But, in the second rectification,

this Oil becomes very perceptible; for it then separates, in a great

measure, from the Salt, and remains at the bottom of the cucurbit,

floating on the phlegm, which is also separated from the Salt.

The Salt is then whiter, more volatile, and purer; yet it is still

far from being brought to the utmost degree of purity, even by this

second rectification. It requires a third, a fourth, and even many more

rectifications, to purify it perfectly: every rectification separates

from it some oily particles: and if you should resolve to go on

rectifying till you can separate no more Oil, there is reason to think

this Salt would be entirely decomposed; because there is necessarily a

certain quantity of Oil in its composition, without which it would not

be a Volatile Alkali. You must therefore desist from rectifying it any

further, when you find it very white, and very light; and shut it up in

bottles hermetically sealed.

It often happens that Volatile Salts, though of a beautiful white after

rectification, grow yellow after being kept some time in close bottles.

This is occasioned by the Oil they contain disengaging, and discovering

itself by degrees. To remedy this inconvenience, Mr. Boerhaave

proposes to mingle the Volatile Salt, which you intend to purify,

with four times its weight of pulverized chalk, thoroughly dried, and

even heated; to put the mixture into a glass alembic, and distil it

with a gentle heat. By this means the Salt rises exceeding pure and

very white; because the chalk absorbs most of its Oil, and frees it

therefrom. He adds, that Volatile Salt thus purified may be kept a long

time, and will retain all its whiteness.

If a Volatile Alkali thus purified be combined, to the point of

saturation, with an Acid, such as the Marine Acid for instance; the

result of this union, as we shall afterwards see, will be a Sal

Ammoniac, from which the Volatile Alkali may be separated by the

intervention of a Fixed Alkali. A Volatile Alkali that hath passed

through all these trials will then be in the highest degree of purity

that Chymistry can bring it to, and appears constantly the same, from

whatever substance it was originally obtained: which proves that

if Volatile Alkalis, extracted from different vegetable and animal

substances, seem to differ from each other in some respects, this can

arise only from the heterogeneous matters with which they are mixed;

but that, at bottom, they are all constituted of one single principle,

which is constantly the same, and exactly alike in them all.

It is of the last consequence, on all occasions where a Volatile Alkali

is to be distilled in a concrete form, to make use of subliming vessels

with very large necks, that it may have room enough to make its way to

the receiver with ease; for otherwise it may choak up the passage, and

burst the vessels.

PROCESS II.

_Volatile Alkalis combined with Acids. Sundry Ammoniacal Salts. Sal

Ammoniac._

On a Volatile Spirit or Salt pour gradually any Acid whatever. An

effervescence will arise, and be more or less violent according to the

nature of the Acid. Go on adding more Acid in the same manner, till no

effervescence be thereby excited, or at least till it be very small.

The liquor will now contain a semi-volatile Neutral Salt, called an

_Ammoniacal Salt_; which may be obtained in a dry form by crystallizing

as usual, or by subliming it in close vessels, after the superfluous

moisture hath been drawn off.

_OBSERVATIONS._

Volatile Alkalis have the same properties with Fixed Alkalis, fixity

only excepted: so that a Volatile Alkali must produce an effervescence

when mixed with Acids, and form therewith Neutral Salts, differing from

each other in nothing but the nature of the Acid in their composition.

It must be observed, that, on this occasion, the point of saturation

is very difficult to hit; owing probably to the Volatility of the

Alkali, which, being much lighter than the Acid, tends always to

possess the uppermost part of the mixture, while the Acid sinks to the

bottom: whence it comes to pass, that the lower part of the liquor is

sometimes over-charged with Acid, while the upper part is still very

Alkaline. But it is most eligible that the Alkali should predominate

in the mixture; because the excess of this principle easily flies off,

while the moisture is evaporating, in order to the crystallization or

sublimation of the Ammoniacal Salt; which being only semi-volatile

resists the heat longer, and remains perfectly Neutral.

If the Vitriolic Acid be combined with a Volatile Alkali, and the

mixture distilled in a retort to draw off the superfluous moisture,

a liquor comes over into the receiver, which smells strong of

a Sulphureous Acid. Now, as the Acid of Vitriol never becomes

sulphureous, but when it is combined with an inflammable matter, this

experiment is one of those which demonstrate that Volatile Alkalis

contain a very sensible quantity of inflammable matter. This same

liquor tastes of an Ammoniacal Salt; which proves that it carries up

with it some of the Neutral Salt contained in the mixture. The rest

of this Salt, which is called _Glauber's Secret Sal Ammoniac_, or

_Vitriolic Sal Ammoniac_, sublimes into the neck of the retort. It is

very pungent on the tongue; it crackles a little when thrown on a red

hot shovel, and then flies off in vapours.

The Ammoniacal Salt formed by the Acid of Nitre exhibits much the

same phenomena; but it requires greater care in drying and subliming

it, because it hath the property of detonating all alone, without the

addition of any other inflammable matter: and it will infallibly do

so, if too strong a fire be applied towards the end of the operation,

when it begins to be very dry. This property of detonating by itself it

derives from the inflammable matter contained in the Volatile Alkali

which serves for its basis: and this is another demonstrative proof of

the existence of such an inflammable matter in the Volatile Alkali.

This Salt is called _Nitrous Sal Ammoniac_.

With the vegetable Acids, that of Vinegar for instance, is formed an

Ammoniacal Salt of a singular nature, and which can scarce be brought

to a dry form.

A Volatile Alkali, combined to the point of saturation with the Acid

of Sea-salt, forms another Neutral Salt, which takes a concrete form

either by sublimation or crystallization. The crystals of this Salt are

so very soft and fine, that a parcel of it looks like cotton or wool.

This is the Salt properly called _Sal Ammoniac_. It is of great use

in Chymistry and in manufactures: but that which is daily consumed in

great quantities is not made in the manner above mentioned. It would

come extremely dear if we had no other way of procuring it, but by

forming it thus with the Acid of Sea-salt and a Volatile Alkali. This

Salt, or at least the materials of which it is formed, may be found

in the fuliginosities and soots of most animal, and of some vegetable

substances. The greatest part of what we use comes from Egypt, where

vast quantities thereof are made.

The method of preparing Sal Ammoniac in Egypt was not known among us,

till Mess. Lemaire and Granger, two of the Academy's correspondents,

gave in several Memoirs in which that business is described with great

accuracy, from their own view on the spot. Their Memoirs inform us,

that chimney-soot alone, without any additament, is the matter from

which they obtain their Sal Ammoniac; that those chimneys under which

nothing is burnt but Cow's-dung furnish the best Soot. Six and twenty

pounds of that Soot yield usually six pounds of Sal Ammoniac.

"The operation takes up about fifty, or two and fifty hours. The

vessels in which they put the soot are ballons of very thin glass,

terminating in a neck of fifteen or sixteen lines long, and an inch

in diameter: but they are not all of the same size. The least contain

twelve pounds of Soot, and the greatest fifty; but they fill them only

three quarters full, in order to leave room for the sublimation of the

Salt.

"The furnace, in which they place these ballons, consists of four

walls, built in a quadrangular form. The two front walls are ten, and

the sides nine feet long: but they are all five feet high, and ten

inches thick. Within the quadrangle formed by these walls three arches

run lengthwise from end to end thereof, at the distance of ten inches

asunder. The mouth of this furnace is in the middle of one of its

fronts, and of an oval form; two feet four inches high, and sixteen

inches wide.

"The ballons lie in the spaces between the arches of the furnace, which

serve instead of a grate to support them. Four of them are usually

placed in each interval; which makes sixteen for one furnace. They are

set at the distance of about half a foot from each other, and secured

in their places with brick and earth. But they leave about four inches

on the upper part of the ballon uncovered, with a view to promote the

sublimation, as they also do six inches of the inferior part, that the

heat may the better act on the matters to be sublimed. Things being

thus prepared they first make a fire with straw, which they continue

for an hour. Afterwards they throw in Cow's-dung made up in square

cakes like bricks. (The want of wood in this country is the reason that

they generally make use of this fuel). These cakes of dung add to the

violence of the fire, which they continue in this manner for nineteen

hours; after which they increase it considerably for fifteen hours

more; and then they slacken it by little and little.