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Title: Chemistry
Original Title: Chymie
Volume and Page: Vol. 3 (1753), pp. 408–421
Author: Unknown
Translator: Lauren Yoder [Davidson College,]
Subject terms:
Particular physics
Original Version (ARTFL): Link

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Citation (MLA): "Chemistry." The Encyclopedia of Diderot & d'Alembert Collaborative Translation Project. Translated by Lauren Yoder. Ann Arbor: Michigan Publishing, University of Michigan Library, 2004. Web. [fill in today's date in the form 18 Apr. 2009 and remove square brackets]. <>. Trans. of "Chymie," Encyclopédie ou Dictionnaire raisonné des sciences, des arts et des métiers, vol. 3. Paris, 1753.
Citation (Chicago): "Chemistry." The Encyclopedia of Diderot & d'Alembert Collaborative Translation Project. Translated by Lauren Yoder. Ann Arbor: Michigan Publishing, University of Michigan Library, 2004. (accessed [fill in today's date in the form April 18, 2009 and remove square brackets]). Originally published as "Chymie," Encyclopédie ou Dictionnaire raisonné des sciences, des arts et des métiers, 3:408–421 (Paris, 1753).

Chemistry, Encyclopedic order. Understanding. Reason. Philosophy or Science. Natural Science. Physics. General Physics. Particular Physics, or the physics of large and small bodies; Physics of small bodies or Chemistry . Chemistry is little cultivated among us; this science is not widespread, not even among scientists, in spite of the claim of universal knowledge which is so dominant today. Chemists make up a very distinct group of people, not very numerous, having their own language, laws and mysteries, and living very isolated amongst a large population which shows very little interest in their activities and expects almost nothing to come from their work. This lack of curiosity, whether real or mock, in any case has little to do with philosophy since it is founded primarily on chance judgments. It is at the very least easy to be mistaken when one makes pronouncements on subjects that one knows but superficially. Indeed, since people have surely been mistaken and even come up with more than one hasty judgment on the nature and the extent of chemical knowledge, it will not be an easy or lightly considered task to determine precisely and incontrovertibly what Chemistry really is.

First of all, those people with the least education cannot distinguish between chemists and glass-blowers; both of these words ring false to their ears. Because people have been more afraid of ridicule than of error, such prejudice has impeded progress, or at least the spread of the art, more than more serious imputations aimed at the science's very heart.

For many uneducated people, being a chemist means having a laboratory, making perfumes, phosphorescent materials, colors and enamels, and being familiar with most chemical processes and some strange and more secret techniques. Or simply put, a chemist is a technician who is familiar with secret processes.

Others, fewer in number, limit the idea of chemistry to its pharmaceutical side. These people always ask after each operation what cure it might offer. All they know about Chemistry are the remedies proposed by practical Medecine, or at best the hypotheses that Chemistry has furnished schools of theoretical medecine.

The following criticism is also frequently heard: the principles of matter assigned by Chemists deal with compounds; the products of their analysis are created by fire; fire, the primary agent of Chemists, alters materials it is applied to and confuses the basic principles of their composition, ignis mutat res . These criticisms are based on the misconceptions I've just described, although they do seem to reflect a knowledge of chemical doctrines and facts.

It seems safe to say that books written by Chemists, masters of the art, are totally ignored. How many physicists ever mention Becher or Stahl? Chemical studies (or rather books about chemical subjects) written by scientists who are famous for other reasons are much more widely known. That's the case, for example, of Jean Bernouilli's treatise on fermentation and the famous Boerhaave’s scholarly compilation about fire. Such works are known, quoted and praised, whereas the higher ideas and unique details that Stahl has published in both areas are recognized by only a few chemists.

Some chemistry can be found in the works of the true physicists, for indeed many of them deal with chemistry, including views on general systems and fundamental doctrinal principles. This kind of chemistry, however, and it is the most widely known, has the great disadvantage of not having been sufficiently discussed or verified in every detail and measured againsts facts. What Boyle, Newton, Keill, Freind, Boerhaave, etc. have written is marked by lack of experimentation. So we can't expect to get a true picture of Chemistry by studying such people.

One might expect to get a valid picture from the ancients. They are rich in facts and in true chemical knowledge. They are indeed Chemists, but their obscurantism is truly frightening and their enthusiasm is disconcerting for the wise and staid demeanor of sensory philosophy. And it is quite difficult to see true Chemistry in the sacred and divine art and in Nature's rival and corrector as seen by the first fathers of the science.

Since Chemistry has taken on the form of true science, that is, since it has accepted the prevalent physical systems, since it has become successively Cartesian, corpuscular, Newtonian, academic or experimental, varius chemists have proposed neater models, models more in line with ordinary scientific logic. They've borrowed the tone of prior ideas. But perhaps that's a reason for criticism. Should they not have more carefully preserved their independence? Didn’t they have a special right to claim their independence, given the nature of their study? Are Chemists’ temerity (some say folly) and enthusiasm really any different from the creative genius of a systematic spirit? And should we banish this systematic spirit on the grounds that it’s premature development produced errors in less happy times? Simply because their ambition led them to make mistakes, must we conclude that the desire to improve is a mistake? Would it have been better if the world of genius brought back to general awareness by certain great courageous men of our time had came back through revolution?

In any case, the modern style, including attention to detail and the slow, timid, and circumspect advance of the physcial sciences has dominated absolutely in our basic texts and our bodies of doctrine. These books are nothing more (or at least their authors don't claim they are anything more) than well-organized collections of facts that have been chosen carefully and strictly verified, of clear, wise and sometimes new explanations, and of useful corrections to certain processes. Each section of such books may be perfect, or at least exact. But what is missing is the nexus, the whole, the system, and especially what I might call the path which Chemistry might take to incorporate new objects of study, to enlighten other sciences, in short, to grow.

It's primarily because of the mediocre nature of such treatises that people see Chemists in a false light as simply technicians or experimenters. And that's also why people never suspect that there might exist a Chemistry that is truly philosophical, reasoned, deep and transcendent. Or that there might be chemists who dare look beyond the senses, who aspire to a higher order, and who, though remaining within the confines of their art, are able to envision elements of the nature of the world.

Boerhaave made it clear at the beginning of his Chemistry that chemical objects can be sensed, can take up space and can be held in containers, corpora sensibus patula, vel patefacienda, vasis coercenda, etc. The first historian of the Royal Academy of Sciences, when asked to compare the way two famous scientists approach philosophy, one of them being a chemist and the other a physicist, gave the following distinction: "Chemistry, using certain visible operations, reduces bodies to specific palpable form, such as salt, sulfurs, etc., but Physics, by delicate speculation, acts on principles the way Chemistry does on bodies, and reduces them to other simpler principles, into smaller bodies, propulsed and formed in infinite ways. And that's the primary difference between Physics and Chemistry. The spirit of Chemistry is more complicated, more hidden. It is more related to compound substances, whose principles are intermingled. The spirit of Physics is cleaner, neater and less encumbered. It goes back all the way to the origins, whereas Chemistry doesn't go so far." Mém. De l’acad. Des Sciences, 1699.

Chemists wouldn't be very strongly tempted to claim for themselves some of the prerogatives on which Physics is said to be superior, for example, the "delicate speculations" by which it reduces chemical principles into little bodies “propulsed and formed in infinite ways.” But they would not agree with the comment that the spirit of chemistry is more complicated, more hidden, and not as neat and simple as the spirit of physics. And they would agree even less that Physics goes beyond Chemistry. They would claim on the contrary that Chemistry can penetrate certain bodies about which Physics knows only the surface and the outside shape; quam & boves & asini discernunt , said Becher bluntly in his physiq. soûterr. And they don't believe they would be proposing a foolhardy paradox if they were to say, concerning most of the questions raised by the phrase “it goes all the way back to the origins,” that Physics has thus far only confused abstract notions with the truths of existence, and consequently it has not understood for example the nature of the composition of compounds, or the nature of matter, its divisibility. It has failed to understand claims about matter’s homogeneity, the porosity of bodies, the essence of solidity, of liquidity, of softness, of elasticity, claims about the nature of fire, of colors, of odors, the theory of evaporation, etc. Such chemists, rebellious enough not to recognize the sovereignty of Physics, would claim that Chemistry has the capacity to explain such things a great deal better, though one must admit that so far it hasn’t clearly done so and that it has failed to point out its natural advantages. And indeed, we must admit that there are even some chemists so unaware that their art can be raised to such levels that if they happen across such statements, either in books or from the mouths of some of their fellow chemists, they would be quick to look down their noses and say “that must be physics.” By that judgement all they do is show how little they understand either Physics, to which they attribute what doesn’t belong there, or Chemistry, which they deprive of what is rightly Chemistry’s alone.

Whatever our claims might be, the idea that Physicists had of themselves and of Chemists in 1669 is precisely what the most illustrious of them still have. Their opinion deprives us of support which we would proudly accept and does real harm to Chemistry, irreparable harm. For they discourage young vigorous minds from undertaking the study of Chemistry. Such minds could never allow themselves to be dragged from procedure to procedure nor content themselves with meager, dry, weak and isolated explanations. But they could have become zealous chemists if someone would have shown them how much Chemistry could offer to eager minds and how much they could in turn contribute to Chemistry.

It is surely very difficult to destroy such misconceptions. A revolution that would give Chemistry the rank it deserves, that would put it at least at the same rank as mathematical Physics, can be accomplished only by a courageous and enthusiastic chemist. Such a person, occupying a respected position and knowing how to use favorable circumstances to his advantage, might be able to get the attention of scientists, first by a captivating presentation and a firm positive tone, followed by the real reasons after initial prejudice against Chemistry has weakened.

But, while we're waiting for some new Paracelsus to make the claim that all the mistakes that have deformed Physics come from the same source, and that is that people didn't know their Chemistry and gave themselves airs, thinking they could philosophize and explain the natural world, whereas Chemistry, being the basis of Physics, is the only science that can do so, etc., already some like Jean Keill have said as much in terms of Geometry, as has Mr. Desaguliers in the preface to his course in experimental Physics. But while we’re waiting, as I said, we will nonetheless attempt to present Chemistry in such light as it may be recognized worthy by Philosophers. And perhaps we can suggest how they might find it useful.

Our present goal is to convince such people, although we realize that we can't raise Chemistry to the level it deserves by showing them its philosophical side, that we can't do for Chemistry what elegant machines, optics and electricity have done for Physics. But since there are able chemists who already have public esteem, and since they themselves can present Chemistry in a way most apt to propogate it, we have decided to lean on their zeal and their talents.

But, in order to present general philosphical Chemistry in the way that I understand it (and I say "present" or “announce” without going further), and in order to indicate sufficiently its method, its doctrine and its scope of activity, and especially its relationship with other sciences, by which I would like to begin, we must go back to some basic considerations about the scope of these branches of science.

Physics, understood broadly to be the science of bodies and their movements, can be divided first of all into two distinct primitive branches. The first branch studies bodies by examining their exterior qualities, by considering physical objects as simply existing and having qualities that can be captured by the senses. The sciences included in this division are the different parts of Cosmography and pure Natural History.

The causes of the existence of such objects, their qualities that can be captured by the senses, their internal properties or forces, the changes they might undergo, as well as the changes, laws, order or succession of such changes, those are the areas studied by the second primitive branch of Physics.

But nature can also be considered either as acting in the ordinary course of events by constant natural laws or as being constrained to act by human art. For men have learned how to imitate, direct, vary, speed up, slow down, suppress, complete, etc. various natural operations, thus producing certain effects, which though they may be natural, cannot be seen as happening due to agents acting simply in accordance with general laws of the universe. Therefore we find a well-founded division of the second branch of Physics into two parts. The first part studies changes introduced by non-intelligent agents, and the second, those dealing with human operations and experiments, that is knowledge furnished by practical physical sciences, and specifically by experimental Physics and by different physical arts. Chemists ordinarily designate this double theater of their speculations by the names the laboratory of nature and the laboratory of art .

All changes operative in bodies, either by nature or by art, can be reduced to three categories. The first includes those that permit bodies to move from a nonorganic to an organic state, and vice versa, as well as all those that depend upon or constitute organic systems. The second includes those changes that belong to the union or separation of constituant parts of compounds or of materials making up nonorganic compounds, all the phenomena of combination and decomposition used by modern chemists. The third category, finally, includes all those changes that push masses and compound bodies from rest to movement, or from movement to rest, or which modify different kinds of motion and tendancies.

One assertion, evidence for which we can find in Mr. De Buffon's discoveries, is that organic molecules and organisms obey laws that are essentially different from those that govern the motion of matter that can be put at rest or is inert. Errors made by doctors who have tried to explain animal organisms by the laws of mechanics tell us the same thing. Consequently, phenomena of organisms must be the object of a science that is essentially different from the other parts of Physics. That consequence cannot be contested.

If it is true that the principles governing the composition of bodies are different from those concerning compounds or masses, the usefulness of the above distinction will be fully demonstrated. That indeed is what Chemists claim, and our goal is to explain and expand their doctrine in that regard. We must admit that their doctrine is not clear, precise or profond, not even among those authors of Chemistry whose style tends toward philosophy and who appear to be the most interested in such questions. Indeed, Stahl himself, who epitomizes the dual character we've just described, has not sufficiently developed his thoughts on such differences. Nor has he pushed them far enough or considered them fully from his own point of view. See his Prodromus de investigatione Chimico—physiologica , and his observation de differentia mixti, texti, aggregati, individui .

I shall call mass or aggregate bodies any uniformly dense assemblage of continuous parts, parts that are linked by a force which resists their dispersion.

This relational force, whatever its cause might be, I shall call a relationship of mass.

The continuity essential for such an aggregate doesn't necessarily mean that all parts are contiguous. That is, it is possible for this relationship of mass to exist among parts that are not in contact, whatever material provides the linkage, or even if this linkage is non-material.

The relationship of mass supposes homogeneity in the aggregrate. For an assemblage of heterogeneous parts does not constitute a whole whose parts are linked by that relationship. Thus, a cloudy liquid or a chunk of clay filled with pebbles, when considered as a whole, are not aggregates, but simple confused mixtures, which we claim are different from aggregates.

According to this definition, it is evident that heaps or collections of simply contiguous parts, such as powders, are not aggregates, but they can be collections of aggregates.

And, if we are still considering organisms, it is also clear by the same definition that they are totally excluded from the class of aggregates.

Modern Physicists call the parts of an aggregate molecules or masses of the final compostion (or the final order), or derived compounds. Earlier Physicists more properly called them intergral parts or simply corpuscles . I say more properly, for it is gratuitous, to say the least, that modern Chemists maintain that corpuscles forming material compounds should be considered as masses.

Corpuscles, considered as intermediate components, are assumed to be inalterable. That is, an aggregate can exist in its specific form only if its constituant parts are unaltered. For example, when tin decomposes during calcination, its constituant parts are no longer tin, even if melting it down seems to produce a relationship of mass or a simple aggregate, tin oxyde glass.

I am willing to allow perfect and imperfect aggregates. The first category includes those that fit the terms of the definition exactly and for which by physical means there is no way to determine whether or not they fit the definition. The imperfect aggregates are those in which some imperfection can indeed be determined by physical means. My perfect aggregate is the similar mass that Mr. Wolff has defined ( cosm .249) and whose existence in nature he has denied ( suiv .), and that he also seems to include under the name tuxtura . Cosmolog.nat. 75.

An aggregate's imperfection always lies in a defect of uniform density.

Pure liquids, homogeneous vapors, air, solid bodies like metals and glass, some non-organic animal and vegetable substances such as vegetable and animal oils and butters, liquid balms, salt cristals, and soft bodies that take the shape of their containers are perfect aggregates. Hard stones, oven-baked clay, compact stony conglomerates, soft bodies that are non-uniformly compacted, metals that are hammered or drawn, extracts, greases, etc, are imperfect aggregates.

My way of understanding all perfect aggregates is the idea Newton wished to present of the expandability and compressibility of air ( see xxxj .) Mr. Desaguliers has expressed the same idea with more precision (see his second dissertation on rising vapors in his course on physics ( leç. xj. ). I picture all perfect aggregates, except absolutely dense mass, if such exists in nature, as a conglomeration of non-contiguous corpuscles, equidistant from each other. I won't pause here to establish this physical paradox because it serves me equally well whether it is a supposition or demonstrated truth. My goal is less to determine the internal disposition or composition of my aggregate than to give an accurate description of its state.

The integral parts of an aggregate, considered together and separately, can be simple elementary bodies, or atoms. Or they can be material formed by the union of two or more simple bodies which Chemists call mixtures . Or formed by the union of two or more mixtures, which Chemists call compounds . Plus there are perhaps other combinations which we do not need to describe here.

A mass of water is an aggregate of similar simple bodies. A mass of gold is an aggregate of similar mixtures. An amalgam is an aggregate of similar compounds. We choose the word "similar" with care in order to clarify that the aggregate's homogeneity persists even with the non-simplicity of its intergral parts and that it is absolutely independent of their own homogeneity. Its uniform density is also independent of the degree of density of its parts or of their varying porosity.

This is not the moment to demonstrate all the truths that flow from the above explanation. For example, the fact that there are several essentially different elements, that the homogeneity of matter is a chimera, that inalterable materials such as water are composed of elements and the small edifice proposed by the Corpusculars and the Newtonians to help us understand the concept of a water particle rest on a shaky foundation and faulty logic. Thus, since we are writing an encyclopedia article and not the final chapters of a general scientific treatise on Chemistry, we simply propose these truths rather than trying to prove their validity. All the facts, operations, procedures and attention to detail that fill so many introductory texts could serve as the basis for these universal notions and for those that will follow. These notions can then shed the name of "suppositions" and take on the name “axioms.” They can serve initially to distinguish for any material what belongs to the mass and what belongs to its intergral parts .

For example, one can conclude from the very statement of facts that a body's mechanical properties belong to its mass, that it is by their mass they they exert presssure, have weight, resist movement, and act on other bodies with a given force (for we are not dealing here with common or essential properties—their mobility, their gravity or their absolute inertia). In sum, their shape, size, movement and situation, considered as mechanical principles, are a function of their mass. As for movement, although Physicists judge the movement of the whole as the sum of the movement of its parts, they nonetheless agree that during any movement the parts remain at rest in relation to each other.

All changes that an aggregate undergoes concerning the disposition and juxtaposition of its parts also affect the aggregate. We are unable to examine certain areas here. For example, rarescibility, elasticity, divisibility, ductility, etc., depend only on the aptitude of change and not on internal changes affecting the constituant molecules. However in any case there are bodies whose integral parts are unaffected by such changes, whatever these bodies might be. Observation of internally inalterable bodies such as water, air, gold, mercury, etc., shows that all the above properties can be considered due to the two causes just given, although the exact cause of the specific degree of each of these properties can be found of course in the internal make-up or in the essence of the integral parts of each aggregate.

We can state the same thing about certain internal movements that some aggregates undergo, for example, the movement that is the essence of liquidity, according to Descartes and the witness of our own senses. I use the phrase witnessed by our own senses because the act of boiling, which we can easily sense, is different from liquidity only by degree, and thus, strictly speaking, any liquid in its state of calm liquidity is a body that can boil. That is, it can be agitated by an outside agent, fire, and it is not a body whose parts must necessarily remain at rest, as more than one Newtonian has proven by geometrical axioms. Axioms in geometry are all well and good. But geometrical Physicists expose such axioms to the ridicule of non-geometrical Physicists whenever they propose a demonstration as a replacement for a physical fact, and a false or gratuitous supposition, either tacit or expressed, in place of a physical principal based on observation and which can be captured by the senses, as in the above case. In this matter I can believe D'Alembert as readily as I believe Stahl who decries transmutation . For example, when Mr. Desaguliers rigorously demonstrated that all parts of a homogeneous liquid are at rest and that quite simply, the liquid could not come to a boil, he did so, it seems to me, because he tacitly assumed that all the parts of a liquid are free, sui juris . Simple observation, however, demonstrates to the senses that fire agitates the component parts continuously and that liquidity cannot exist without heat. That is what almost all the Newtonians seem to disregard, although their master so stated expressly. See optiq. quest. Xxxj. To return to my subject, I claim that liquidity and boiling, which is liquidity taken to the extreme, can be related only to mass, and that it is so for water and for certain other liquids.

The qualities of bodies that our senses can determine are not always the same as those of their constituant parts. A supple material can be composed of parts that are quite stiff, as we agree is the case of water. It would be ridiculous to look for the cause of sound in the changes taking place among the integral parts of a sonorous body. And the perceived color of a mass of gold, it's yellow nuances, doesn't belong to the tiniest particle which makes up gold, even though that particle must have color, and even though facts demonstrate that it does indeed, but not in the same way as the mass. This could be proven completely ( see the chemical doctrine on colors at the word Phlogistique ), but, as I’ve said, I’m not concerned with establishing such truths just now. It’s enough for me to establish that it is at least possible to conceive of a mass formed by particles which have none of the properties of the mass itself. That it is very easy to imagine a mass of gold, that is yellow, shiny, ductile, compressible, divisible by mechanical means, able to become a liquid, condensable, elastic, having nineteen times the weight of water. One can imagine such a body formed by an assemblage of particles that are also gold, but which have none of the qualities that I’ve just outlined. That assertion is so obvious from what I’ve just proposed that proof based on experiments seems as unnecessary as trying to prove experimental Physics by demonstrating the force of levers. However, if some readers are curious about further proof, they can find it in what we will say later about the imitation of gold.

I judge all these qualities as external , or physical qualities, and I will note immediately that they are also accidental , according to scholastic language, because they could disappear without the corpuscle being destroyed or cease being material. Or, which is to say the same thing in another way, they are unnecessary for the specification of the body; not only because they could disappear without the specific nature of the body being changed, but also because they could also be found in a body of another variety. For although it is difficult to find two bodies internally different but having many similar external qualities, and although this difficulty is still great even when one chooses one of the two bodies from among the most extreme in its category, the most perfect as is gold among the metals, the external similarity doesn't clash with essential internal differences. For example, I could place gold and another body in such a way that they look alike from the outside and even so that they have the same specific gravity. Though it is difficult to find a non-metallic material with the same specific gravity as gold, there is nothing easier to do than reducing gold's specific gravity. The man who can bring these two bodies to close external resemblance can say of his imitated gold en aurum Physicorum , just as Diogenes said about his crested rooster en hominem Platonis .

In addition to all these properties that I have called external or physical , I also observe in every aggregate qualities that I might generically call internal for the time being, expecting that I'll one day be able to call them chemical and to distinguish them by that particular denomination of other qualities of the same kind, such as the very common qualities of bodies—occupying space, impenetrability, inertia, mobility, etc. The qualities I'm talking about here are particular internal qualities. They constitute a body as it really is, so that water, gold, saltpeter, etc, are water, gold, saltpeter, etc, and not other substances. For water, these qualities include simplicity, volatility, the faculty to dissolve salts and to become one of the materials of the resulting mixture, etc. For gold, these qualities include its metallic nature, its fixity, its solubility by mercury and by a mixture of hydrochloric and nitric acid. For saltpeter, we see neutral salinity, the form of its crystals, its ability to be decomposed by phlogiston and by vitriolic acid, etc. All of these qualities belong essentially to the integral parts.

All of these qualities depend upon each other in a way which it is not necessary to elaborate here, and they are all quite common. Gold, for example, is soluble by mercury as a metal. As a perfect metal it is not transformable. It is soluble in hydrochloric/nitric acid according to a degree of specific affinity as a perfect metal, that is as gold.

As far as these external qualities are concerned, some of them are not essential to bodies except relative to our own experience, our current knowledge. The non-transformability of gold, the volatility of mercury, the inamalgability of iron, etc., are internal qualites of this kind. The source of problems of the least common practical Chemistry lies in the discovery of contrary qualities.

There are other internal properties that are so inherent to bodies that they can exist only in conjunction with those bodies. These are the properties whose very cause resides in the elementary substance or in the nature of the mixture of specific corpuscles of each body. Thus saltpeter must be formed by the union of the acid we call nitric acid and of fixed alkali, and water is composed of a specific element, etc.

All the distinctions proposed up to now can be considered as simple truths of analytical precision since we have considered only the qualities of bodies. Now we shall see that the differences they display as physical agents are no less remarkable.

1. Masses exert on each other actions which are distinct from the action inherent in corpuscles, and these actions follow laws that are absolutely different from those governing effects on corpuscles. Bodies bump and press against each other, resist each other, divide, are lifted up, are lowered, surround themselves, penetrate each other, etc., some of them because of their velocity, their masse, their specific gravity, their consistence and their respective shapes. And they follow similar laws, whether the actions have to do with homogeneous masses or with those that are specifically different. A marble column, all things being equal, can support a mass of marble or a mass of lead. A hammer made of any appropriate material can drive in a nail of any appropriate material. The mutual interactions of corpuscles are not related to any of these qualities. The only interaction the corpuscles undergo is the interaction related to their aggregate union or separation, to their mixture, to their decomposition and other similar phenomena. There is nothing related to shocks, to pressure, to friction, to weaving, to penetration, to wedges, to levers, to velocity, to size, to shape, etc., although certain forms and sizes may seem to be necessary for certain actions. These actions depend upon the internal qualities of corpuscles, among which homogeneity and heterogeneity need to be considered initially as essential conditions. For the formation of aggregates happens only with homogeneous substances, as we've noted earlier. Heterogeneity is on the other hand essential in mixtures. ( see Mixture, Decomposition, Separation)

2. All masses gravitate toward a common center or have weight. They all have measurable weight in proportion to the quantity of matter in a specific volume. The absolute gravity of each corpuscle cannot be demonstrated ( See Principles & Phlogiston). Their specific gravity is not known.

3. Masses hold together due to their proximity, their size and their shape. Corpuscles do not obey the same law. It's because of their relationship or affinity that they unite. ( See Rapport). Reciprically, masses are not subject to the law of affinities. Dissolving action supposes on the contrary the aggregrate's destruction ( see Solvent), and from the union of one mass with a mass of a different nature a new homogeneous body can never result.

4. Corpuscles can be separated from each under the effect of heat, and that case doesn't need to be explained by Newton's repulsion . Heat does not cause masses to move away from each other. ( see Fire)

5. Certain corpuscles, but no mass, can become vapor. ( See Volatility)

So far we have opposed corpuscles to aggregates only as each is considered separately, and we have not looked at the interior composition of corpuscles. This aspect can provide us with new distinctive characteristics, which follow:

1. Aggregates are homogeneous. Corpuscles are either simple or composed of materials that are essentially different. The first part of this proposition is founded on a definition or a query. The second expresses a similar truth, and besides it can be supported by our vast experience in this matter. ( See Mixing)

2. Materials constituting compound corpuscles differ not only from each other, but also from the corpuscle which results from their union and consequently from the aggregate formed by the assemblage of these corpuscles. Thus fixed alkali and nitric acid are different from saltpeter and a mass of saltpeter. If such division is continued all the way to the elemental level, we have the basis of the difference between a mass and a simple body. ( See our doctrine on elements under the word Principe .)

3. Principles of mixtures or of the composition of corpuscles are connected by a link different from the one governing the formation of aggregates or relationships of mass. The first can be broken down by mechanical as well as by chemical means. The second can be separated by chemical means alone, for example, dissolution and heat. And in certain cases, the link is indissoluble, at least by ordinary means. Gold, silver, mercury and a limited number of other bodies are mixtures of this last type. ( see Mixture).

The limits imposed on us do not allow further consideration of these ideas. The propositions we have developped, however, though they are simply stated for the most part, I believe sufficiently prove the properties of masses and the properties of the different principles which explain them. They can can indeed be understood by abstract considerations and are physically different in several ways. Therefore we can now suspect that the physical nature of non-organic bodies can be divided according to such differences into two independent sciences, at least in terms of their specific interests. And indeed, these two sciences already exist, for such division is quite natural. The main interest of each science so closely matches the two categories we've just established that the division preceding its rationale is a new proof of the truth that allows us to distinguish between them.

One of these sciences is ordinary Physics, not the universal Physics that is so often laid out at the beginning of texts in Physics, but rather a less ambitious Physics that is actually described in these texts.

The second is Chemistry .

Ordinary Physics, which from now on I shall call simply Physics , is limited to properties of masses, or at least that is its primary object. Any reader can verify that statement: 1. from the table of contents of any treatise on Physics, 2. by going to the trouble of skimming the definitions of the general categories that are examined and the different manifestations of those categories (for example, movement), and then determining for which bodies physicists study movement, and finally , 3. by considering the limited number of particular objects dealt with by Phyics and which we also share, such as water, air, fire, etc. Research of that kind will reveal that Physics always deals with masses and that movement which interests Physicists is the movement unique to masses. For the Physicist, air is a liquid that after compression can easily regain its prior form, that takes on equilibirum with liquids it contains at particular altitudes and circumstances, whose currents known as winds have particular velocities, and that is a material through which sound rays travel. In short, for a Physicist, air is simply atmospheric air, and consequently it is an aggregate or a mass. For him, water is a non-compressible wet liquid, able to change to ice and to steam, subject to all the laws of hydraulics and hydrostatics, and it is the material of rain and other water-based precipitation, etc. But all of these properties are clearly properties of mass, excepting humidity. And humidity is difficult to understand in passing, for I would invite anyone to show me any liquid that is not wet, not even excepting mercury, and I will agree that humidity might indeed not be a property of every liquid. As far as fire is concerned,and its essential quality as Boerhaave describes this fluid, that is its faculty to rarefy other bodies, it is clear that this property is related to a mass or aggregate of fire. Thus we can affirm that all but five or six lines of Boerhaave's treatise on fire deal with Physics. Light, another general property of fire, belongs to the aggregate of fire alone.

Most physical objects can be sensed either directly or through their immediate effects. A mass has a determinable form. A mass in movement crosses measurable space in measurable time. It can be slowed down by detectable objects, and the deceleration can be measured, etc. An elastic mass can be flattened by a shock on a determinable part of its surface, and this action is governed by geometrical precision concerning the shapes, forces, and movements related to such bodies. Mass provides geometers measurable principles, upon which they are able to develop theories , which, since Newton's work endows Physics with such sublime knowledge, are the basis for Physics.

Today's Physics is thus specifically the collection of all physico-mathematical sciences. Up to the present day, we have calculated only forces and effects of masses. For although the deepest operations of transcendent Geometry act on infinitely small objects, these objects pass quickly from abstraction to the state of mass. They are therefore figurative masses, endowed with central forces, etc. Once they are considered as physical entitities, the tiny bodies of the Geometer/Physicist are not to same thing as those corpuscles that we have opposed to masses. Calculations of such bodies done with the wisdom and genius we so admire do not however make it possible to calculate chemical effects, or at least have not led so far to such calculations.

Physicians try to reduce all natural phenomena to mechanical laws, and the most honorable name one can give to the causes they determine, to the agents that they put forward in their explanations, is to call them mechanical .

Physics can speak for itself about the nature of its study that we attribute to it, especially since we haven't tried to take away from Physics what it has usurped from us and the discussion of which should be flattering. All we have said is that the proper object of its study is the consideration of masses.

Chemistry , however, deals primarily with changes involving different orders of principles that govern detectable bodies. The brief outline, both practical and theoretical, that we will try to sketch in a moment should demonstrate Chemistry's object of study.

Before doing that, however, in order to establish the contrast between Phyics and Chemistry , we would like to make the following observations:

1. All chemical movement is an internal movement, the movement of digestion, of fermentation, of effervescence. For Chemists, air is one of the principles of the composition of bodies, especially of solids, uniting with different principles according to the laws of affinity , separating off by chemical means, heat and precipitation . It is volatile, passing directly from the solid state to an expanded gaseous state without ever being liquid even at the coldest known temperatures, a new way of looking at things that offers protections from the pettiness of some physicists. For Chemists, water is an element, or a simple body, indivisible and unchangeable, an idea which goes against the opinions of Thales, Van Helmont, Boyle and Mr. Eller, according to which water unites chemically with salts, gums, etc. Water is one of the materials forming these bodies, and it is the immediate instrument of fermentation, etc. Fire, considered as a particular chemical object, is a principle capable of combination and precipitation, conferring to those mixtures of which it is the principle, color, inflammability, metalicity, etc. And thus, the treatise on fire, known by the name of Stahl's trecenta , is entirely chemical.

We stress the expression fire considered as a particular chemical object , because fire as aggregate , considered as principle of heat, is not a chemical object but an instrument used by the Chemist in chemical operations or a universal agent whose chemical effects the Chemist can observe in nature's laboratory.

In general, although the Chemist works only with aggregates , since bodies appear to a Chemist in that form only, these aggregates are always simply the promptuaria (storehouse) of the truly chemical subjects, that is, of corpuscles. All of the truly chemical alterations that the Chemist attempts can be reduced to two. He may directly attack its integral parts by combining them one with another or in small quantities with the integral parts of a body of a different nature. That process is called chemical dissolution or syncresis. ( See Solvent, Syncresis, and the rest of this article) This dissolution is the only chemical change that can occur with an aggregate of elements. Or, the Chemist can break down the integral parts of the aggregate, and that process is called chemical analysis or diacresis. ( See Diacresis, Analyse Végétal under the listing Plant and the rest of this article). In short, as long as we are dealing only with the relationships of the aggregrate's integral parts with each other, the phenomenon is not chemical, even though it may be caused by chemical agents. For example, even subdividing an aggregate down to its individual units is not chemical. The same is true of the effects of pulverization. In order for diacresis to be a chemical process, it must separate specifically dissimilar parts.

We must also point out that certain internal changes due to the effect of heat on an aggregate body are truly chemical only when the energy from these changes affects the internal make-up of the corpuscles. These changes being in general simply graduated effects from the same cause, they must be considered mixtures or as effects whose physical nature is well-known to the Chemist. Included among such effects due to moderate heat, effects that we shall call specifically physical , are, for example, rarefaction of bodies, their liquifaction, ebullition, evaporation, the exercising of elastic force in compressed bodies, etc. Thus Chemists are also good physicists when dealing with all questions of this kind. It seems to me, that when considering these effects, working from the analogy of those effects whose cause is most obvious (and those are objects that only Chemists examine) with those whose cause is more hidden, I am able to bring together two phenomena that are often considered only separately. For example, the discovery that the mechanism of elasticity is the same in all bodies, that all bodies are susceptible to the same degree of elasticity. It is due only to accidental circumstances that different bodies around us have specific differences in that regard. Elasticity is only a mode of low or high density, and consequently it is always due to heat just like all other phenomena attributed to Newtonian repulsion, which is really only heat. ( See Fire, Rapport)

2. Chemical objects do not act in such a way that they can always be sensed. The immediate effect of fire and dissolution, the two great chemical agents, cannot be perceived by the senses. The time it takes for a mixture to occur cannot be measured, in instanti . Consequently such operations are not calculable, or at least thus far attempts to calculate them have not met with success.

3. Chemists find no glory in working with mechanical agents, and they find it strange that mechanical principles, often just barely distinguishable from an unknown cause, have become so dear to philosophers and that they have caused them to to reject any theory based on unknown causes, as if being true were identical to being intelligible. It is as if the interposition of a mechanical principle between an unknown cause and its effect protected them from the horror of the unintelligible . In any case, the reason Chemists do not accept mechanical principles is not because they have a contrary spirit but because none of the known mechanical principles intervene in the Chemist's operations. People often unfairly criticize Chemists for revelling in their obscurity. For such a criticism to be reasonable, one would need to show them priniciples that are both evident and certain. For Chemists cannot be blamed for prefering obscurity to error. And indeed, if their way of doing philosophy is so ridiculous, then they are ready to share that ridicule with Aristotle, Newton, and a host of ancient philosphers whom Mr. De Buffon has described in his natural history as having a broader philosophy because their genius was unlimited. For the ancients were less disturbed than are we by facts they couldn't explain. They understood nature better. For them a relationship or a correspondance was simply a phenomon, whereas for us, if we aren’t able to associate it with our supposed laws of motion, it becomes a paradox. The ancients realized that nature brings about most of its effects by unknown means and that we are unable to enumerate natures’ ressources. What is truly ridiculous is to attempt to limit nature by reducing it to a number of principles of action and means of operation. To propose a cause, it was enough for the ancients to notice a sufficient number of similar related effects. Is that not what Chemists do?

Chemists would readily and thankfully accept any mechanical explanation that is not contradicted by facts. They would be delighted, for example, to allow themselves to be convinced, along with J. Keill and Freind, that the mechanisim of effervescence and fermentation consists of the mutual action of certain solid elastic corpuscles that act upon each other by force, that take flight in proportion to their elasticity and velocity, and that continue to bump against each other and fly off in all directions. But such an explanation, as ingenious as it is arbitrary, is contradicted by facts that clearly show that effervescent motion and fermentation are due to the production of a subtle expandable body, caused by the general laws of affinities, which are not at all a mechanical principle. ( See Effervescence and Fermentation)

Rather than being reduced to making the simple statement that the process of dissolution is nothing but the result of a certain tendancy or relationship by which two mixable bodies are drawn toward each other, wouldn't Chemists prefer understanding the process through the easily perceived image of, on the one hand, a solvent armed with hard, solid, massive, sharp parts, and on the other a body with an infinite number of pores that are proportional to the mass and form of the solvent? According to that image, after the repeated blows of the solvent's parts against the body to be dissolved, and after the forced penetration of those parts into the pores, then finally the edifice is weakened and its substance breaks apart. That is the picture used by Physicists to explain the phenomenon. Truly Chemists would prefer to understand dissolution in this way, because it is an explanation that rests upon knowledge, that enlarges the scope, and because the prominence of this kind of scholarship is not purely imaginary, and on the other hand, a stark limited description doesn’t bring honor to the scientist. But the explanation fails to take into account essential circumstances of the phenomenon that we have tried to explain, and whether or not the destruction of the dissolved body’s mass, which we have just gone to such trouble to describe, is purely accidental to dissolution, which happens in the same way with two liquids. These accidental circumstances so rivet the theoretician’s attention that he totally neglects dissolution’s essential circumstances, that is the union of two substances. Consequently, it is not possible to accept coins of such spurious alloy. Boerhaave himself, whom we love to cite and praise when the occasion arrises, understood the weakness of the above explanation and refuted it. ( See Boerhaave, de menstruis, Element. Chymia , part . II .)

We would like to believe along with Freind that, of all chemical operations, dissolution is the one that can be explained the most easily by mechanical laws. As does Freind, we would prefer being able to accept the two basic causes. The first is that the solvent becomes lighter with the addition of a less heavy liquid, and the second is that the affusion of a heavy liquid, flowing slowy, carries with it particles of the dissolved body, etc. But too many facts demonstrate the fallibility of such gratuitous suppositions. Pour as much wine alcohol as you like into a totally saturated solution of a neutral deliquescent salt, for example natural sulfur, and not an atom of precipitate will fall out. A body dissolved in the highest concentration of vitriolic acid will remain dissolved if you add water to the solution, etc. Allow mercury, the heaviest liquid found in nature, to drop at whatever velocity you like into a solution of a neutral salt, saline or earthen, and nothing will separate out.

We would be pleased to be able to say along with Boyle that the necessary conditions for immutability are the size of the constituent parts of a fixed body, gravity or the solidity of its corpuscles and finally their inaptitude to evaporate due to their branched, hooked, curved, in sum, irregular forms, which prevent their separation from each other, because it is as if they are interlaced, etc. And we would like to be able to explain volatility by the opposite qualities. But the facts counter all such ideas. For bodies gain volatility as they gain size, as does luna cornea (silver chloride). Should Boyle say to me, and I'm sure that he would, that sea acid makes luna cornea lighter by extending its surface, I'd respond by saying that it should also harm the third condition by increasing the irregularity of its surface and thus strengthen the quality of enlaceability, etc. Some heavy or solid bodies are volatile, such as mercury. Some light and less dense bodies are non-volatile, such as the fixed alkalis, etc. In short, as far as the enlaced shapes are concerned, these spires so dear to Boyle, and indeed so ingenious, we have to admit that we wish they really did exist. But the phenomena of mixtures, of precipitations, of rarefactions, of coagulations, etc., demonstrate too clearly that any union of small particles is done by juxtaposition, and therefore we can’t be comfortable with such purely imaginary mechanisms. In any case, Newton’s teaching, following Becher’s on this point, as I have noted elsewhere, has already discredited those ideas sufficiently without it being necessary to refute them further. In short, the mechanical actions that are proposed here have no basis. We even defy anyone to present an explanation of a chemical process founded on known mechanical laws whose false or gratuitous nature we would not be able to demonstrate.

It is clear that two sciences that consider objects from such different points of view must each inevitably produce particular and distinct knowledge and each develop a number of compound notions. They will each have a certain way of considering and dealing with their subjects, and each way will produce a different language, method and operating procedure. The Physicist will see masses, forces, and qualities. The Chemist will see small bodies, relationships and principles. The Physicist will calculate carefully and will reduce measured effects and forces to theories; that is, he will subject the effects and forces to calculations (for such is the theory of the modern physicist). He will also establish laws that can be almost confirmed by experimentation (I say almost, because Mathematicians themselves admit that the forces whose exercise they calculate are always based on modo nihil obstet , and a case in which there is no opposition does not exist in nature. The theories of Chemists will be vague and approximative. They will be clear explanations of nature and of the chemical properties of certain substances or of particular principles considered in all their combinations that might exist in nature or in the laboratory. They will explain a substance's relationship with bodies and principles of a particular class and all the changes it might undergo or that it might produce through such relationships and combinations. All his work will be based on major basic facts discovered by what I shall call an experimental sense, based indeed on indices gathered from vague experiments or blind searching, but never resulting immediately from those tools. ( See Phlogiston, Nitre, Sea salt , Vitriol, etc.) In short, the physicist's genius, raised to the highest human levels, produces the mathematical principles of Newton, and the corresponding production in chemistry is surely Stahl’s Specimen Becherianum .

As long as Chemists and Physicists each philosophize in their own manner on the objects of their study, continuing to analyze and compare them, bringing them together and combining them, and as long as on their common projects the science that has seen the most sets the tone, things will be fine.

But if some people are confused by the distinctions we have made, either because they haven't suspected the existence and the necessity of this distinction either because of short-sightedness or because they have simply rejected them out of stubbornness, then all is not well. The Chemist, for example, might get involved with physical objects of study, but know only Chemistry . Or the Physicist might propose laws for Chemistry , knowing about only physical phenomena. If the one applies laws pertaining to masses to changes in small bodies, or if the other tries to transfer what happens with small bodies to actions of masses, if one treats more chimico things that are physical, and the other treats more physico things chemical, if one tries to dissolve a salt with a wedge, or make a mill turn by dissolution, then things are not well at all.

Has any one ordinary chemist or physicist ever been able to grasp the general science of bodies and claimed to cover all its common elements with his own particular understanding? If so, the general science he presents will be defective and wrong. When he tries to synthesize, using the principles he thinks are general and the facts he thinks he can count on, he is bound to go astray. All of the Physical Metaphysics, or to use Wolf's word, all the Cosmologies that I am aware of were written by Physicists. Some of them of course, are clearly stamped with genius. I can even go so far as to say that some are impossible to tear down and refute, because they are carefully constructed chains of abstract notions and nominal definitions that the metaphysicist has laid out and circumscribed in his manner. But in spite of that, the general science of the properties of bodies is more solid and real than that. When I use the expression the general science of bodies , I mean physical bodies such as those we can observe in nature, in all their conditions, and not bodies unhampered by those conditions and thus almost destroyed by abstractions.

We can be sure for most of the supposed general truths that are the basis for subsisting general systems, including Leibnitz's famous principles and what Mr. Merian wrote about Spinozism in his treatise on apperception hist. De l'acad. De Prusse 1749 , that it is in the passage from abstraction to the real world that such truths can be tested. All we need to do is try to make that leap and we see that the colossal edifice collapses. From the different sources we have just indicated, thousands of errors have arisen. To those who have proposed them, we could confidently say, borrowing from Apelle’s famous witticism: Lower your voice; our coal porters would laugh if they heard you . The exact list of all such errors that have come to our attention might be useful in the interest of truth and in the interest of supporting good doctrine, but it would be infinite. They would be worth including in a book entitled Institutions of Physics/Chemistry whose goal could be to substitute truth for all those errors. We ask the reader to be content for the moment with those errors we have already cited and others that follow. I don’t know of any true chemist who hasn’t dared to make incursions into the realm of physics. If so, we judge them misguided and as foolhardy has those Physicists who have ventured onto our territory. They are misguided and we disown them.

Chemistry is a science whose business it is to study the separation and union of the principal constituant parts of bodies, in both nature and the laboratory. Its goal is to discover the qualities of those bodies or to find uses for them.

The particular subjects studied by Chemistry are those phenomena, be they natural or artificial, that are related to the separation and union of particles of substances. Natural phenomena include the ripening of fruits, the formation of glues, extracts, resins, vegetable salts, etc., as well as the elaboration and various alterations of food coming from animals and their diverse forms. They also include the generation of metals, stones, natural crystals, fossil salts, sulfur and tars, as well as the impregnation and heat of mineral waters, the heating of volcanoes, the nature of lightning and other expressions of fire in the atmosphere, etc. In short, these phenomena include all of those categorized as Physical Botany, except not those belonging to the organization of the plant world, those belonging to the branch of animal systems based the activity of the humours, those belonging to the chemical world that Becher has called subterranean physics or that are due to chemical changes within bodies or those that give off in the atmosphere certain detached matter from the vegetable, animal or mineral realms.

Artificial chemical phenomena are those that are observed during chemical operations and those upon which the theories of such operations are based.

We call operations all those particular means used to induce in the objects of our study the two great changes enunciated in our definition of Chemistry , that is separation and union.

Such operations are either fundamental and chemical, or they are simply preparatory and mechanical. ( See Chemical procedures).

The two basic general and immediate effects of all chemical operations, that is the separation and the union of principles, are generally better known in the field by the names diacresis and synchresis . The first operation is also called by some chemists by other names, including analysis, decomposition, corruption, solution and destruction. The second operation is also called mixing, generation, synthesis, combination, coagulation and even confusion by some. Each of these terms is understood in a more a less general sense by various authors, and sometimes the same authors use them in different ways. The word mixtion , for example, signifies according to the doctrine of Becher and Stahl at times the union of different principles in general, and at times the union of elements in particular. Or sometimes it refers to the mixtures themselves. ( See Mixing).

The names most in use by French Chemists are analysis and decompostion for the first operation and combination or mixtion for the second.

There are few chemical operations that produce only one of these effects or that can be seen as only diacresis or syncresis. Most are complex. That is, they may produce both separations and unions that are linked by cause and effect. ( See Diacresis, Syncresis, Chemical procedures).

Chemical operations are executed by two general agents, heat and dissolution.

The action of these two agents is complicated in different ways in each operation, according to a limited number of laws which follow.

1. Heat by itself rarely brings about pure separations, and bodies resist its dissociative action all the more when they are less compound mixtures. Simple bodies and perfect mixtures are inalterable by heat alone, at least by the degree of heat that we are able to apply in closed vessels, that is, without the help of air, of water or of fire solutions. Some compounds are totally unaffected by this action. Among these are vitriolic tartar and marine salt, etc.

2. Heat is necessary for any dissolution, at least as a necessary condition. For it is impossible, or extremely rare, for dissolution to take place between two solid or frozen bodies (which is really the same thing), and it can happen only if the aggregation of one of the bodies is very weak. And such weakness can ordinarily be found only in a liquid state, which depends essentially on heat. The chemical axiom menstrua non agunt nisi sint soluta is based on that observation.

3. Not only must any dissolving process by supported by absolute heat to be effective, its degree of activity is proportional to the degree of heat applied, or, speaking literally, to its degree of expansion or rarified nature. As we have already observed, and as we will prove under the word Menstrue , the mechanism of dissolution doesn't depend at all upon the movement of the dissolving body. The separation of the body to be dissolved, in the way that we ordinarily describe it, gives only a false idea of the process. ( See Solvent).

4. When heat is applied to a compound body, not only does it separate its different principle components, but puts them in movement, thus encouraging new combinations. For example, a plant extract is a compound substance that carries within itself principles of reaction. These principles, released by sufficient fire, exerce a solvent action by causing precipitations that allow some substances to separate out and form new combinations. ( See Distillation, Precipitation, Solvent; See Analyse végétale under the word Plant; See Fire)

These releases and new combinations are sufficiently widespread that we have had false ideas about operations that produce them, either because we didn't know what produced them or because we haven't been able to evaluate them. Because some early chemists didn’t undestand the true effects of heat on the principles of bodies they too often used that chemical process. And because the detractors of Chemistry didn’t realize that we could predict and even measure changes, for all the wrong reasons they opposed analysis by fire alone, the only means known to them, and combatted Chemistry which they thought consisted solely of analysis by fire (see the historical sketch at the end of this article, concerning Boyle). Because modern Chemists have discovered a better method, separation by dissolution, they have moved away from the earlier method. And since today’s science is sufficiently advanced to measure the movement of all the reactive agents excited by heat in compound bodies, we can examine them using distillation caused by the violence of fire as easily as we can propose a chemical problem in the manner of Geometers and with the same degree of usefulness.

Chemists use in their operations a variety of instruments: ovens, containers, clay pots, catalysts and other tools that make up the suppellex chimica , laboratory equipment. ( See Chemical instruments, Furnace, Mud, Intermediary, Laboratory, and the particular articles.)

We don't agree with the useless distinction most chemists make between particular and artificial instruments on the one hand and on the other natural and general instruments, including air, fire, water and earth. For one reason, these bodies act through their internal qualities and they also undergo material chemical changes. They are thus no longer instruments but solvants. Air acts as a dissolvant during calcination, fire in reduction, water in fermentation and earth in certain fixations. ( See Solvent). And secondly, the relationship or common quality by which these four substances, considered as mechanical and immediate agents are classified as natural instruments doesn't exist. It is forcing things to try to establish a common identity among fire considered as a heat source, earth that furnishes distilling equipment and ovens, water as a catalyst and air as a current that stirs up the fire in our ovens. Thirdly, two of these so-called natural instruments, earth and water, when they function at a distance, are no different in their essential function than the most mechanical and the most particular instrument. The water in a bain marie, for example, is simply a more useful means in some operations than a similar container filled with sand, ashes, metal filings, etc. It is not an instrument that is truly distinct and necessary in certain operations as some would claim, saying that distillation effected by an open fire or hot sand is essentially different from distillation in a bain marie, simply because it is done over an open fire or in hot sand. Therefore we have to abandon at least these two so-called natural instruments. As for air, its property of exciting fire does indeed distinguish it, at least in practice. But it is so far from acting as a chemical agent in this regard that we cannot really call it a distinct chemical instrument, much less a general instrument. So it is only fire or heat that can be truly considered by the name natural and general instrument. But we prefer using the terms agent or cause , as we have done up to now.

The art of chemistry and its system of instrumentation and rules can be best described using the detailed explanation of the action of the two major agents, the help we get from our instruments and from the theories we use to explain our operations and chemical phenomena. A true treatise of practical Chemistry, a basic treatise on practical institutions, needs to include the entire system. To date there is no such treatise. Practically all books about Chemistry are practical histories of the three natural kingdoms and bear no comparison to our courses in Chemistry in which, following an arbitrary order, beginners learn the basics, such as the history of the chemical properties of various bodies of different types, classes and categories. It is not possible to present this history without explaining how to carry out certain operations and how to use instruments. Such study prepares the eye and the hand for experiments that are essential for helping confirm one's ideas and for helping grasp some fugitive or isolated phenomena that might indeed germinate in the philosopher's mind but whose perception depends on trained senses.

In spite of the usefulness and necessity of such specific pieces of information, a chemist who has mastered them will remain a simple technician unless he is able to group them into a coherent scientific system. That's how we will be presenting them in this Dictionary. ( See the various articles , including Calcination, Cementation, Distillation, Mixing, Procedure, Instrument, etc.)

The three afore-mentioned natural kingdoms are three large divisions into which we have categorized chemical subjects. Minerals, plants and animals make up these divisions. ( See Animal, Plant, & Mineral).

The bodies belonging to each of these kingdoms are distinguishable one from another by their simplicity or by their degree of mixing. They are simple bodies, mixtures, compounds, supercompounds, etc., and their character is essential relative to the ways in which chemists undertake to examine them. ( See Mixing)

The analysis of all compound bodies has taught us that each of them may be decomposed directly into other substances which are essentially different. These as well can be divided into other substances that are different from each other, and they can be either simple or compound. And this separation can be continued until we get to those elements which, combined, make up the first order of composition, and which are different in nature.

Chemists have generally referred to the different bodies we've just spoken about, considered as the material of other more compound bodies, as principles . They call simple bodies first principles , and sometimes call them elements . To those bodies that they can decompose, they have given the name secondary principles or principled principles. (See the doctrine of the Chemist's principles, the history of errors committed by some Chemists in this area, and the history of even greater errors committed by Physicists who are their adversaries, under the word Principe ).

If a Chemist manages to gather back together in an orderly fashion all those principles that he has separated in the same fashion, and if he manages to recompose a body that he has broken down, he has attained a true demonstration of Chemistry. And indeed, the art of Chemistry has reached this level of perfection in several essential areas. ( See Syncresis).

The use of solvent materials in chemical operations has demonstrated in tiny bodies a property to which I give the general name solubility or miscibility ( see Miscibility) and with which I replace Newtonian cohesive attractions, for that attraction cannot exist between these bodies considered as matter. Matter, the object of a body's properties is only an abstract thing ( see Principles) and miscible bodies are attracted to each other only according to certain relationships that require heterogeneity, in other words, through a relative rather than an absolute property. ( See Rapport).

I can also demonstrate that this solubility in action, or the chemical union (as well as the aggregative union or physical attraction) is continually counterbalanced by heat, and is not succeeded automatically by repulsion. Thus I differ on this matter from the Newtonians in two ways. First, because I know the cause of repulsion, which is always fire. And secondly, because I consider cohesibility and heat as two agents that counterbalance each other and that can dominate each other. Newtonians, on the other hand, consider attraction and repulsion as two isolated phenomena, one beginning when the other ends. ( See Fire, Miscibility;, Rapport).

The relationships and heat that we have substituted for modern Physicists' attraction and repulsion are the two grand principles of all Chemical phenomena.

Those are the first lines of what one might call sapientia chimica . A few half-philosophers might be tempted to believe that we are aiming at high generalizations. But we affirm on the contrary that we have clung to those notions that spring the most directly from concrete facts and knowledge and that can help us understand Chemistry's practical side.

It would indeed be possible to set aside all these numerous distinctions that we have made, all these different ways of looking at bodies, if we were to consider them from one of those superior vantage points which often demonstrate more scope than genius, paying more attention to cause and effect. But such efforts would be harmful to practical science. It would not be helpful to those who are unable to grasp the larger as well as the microscopic view. It would be harmful to those who lack the capacity that a few extraordinary men have to focus their intellectual faculties on abstract meditations, to move beyond the philosophical lethargy produced by their senses in suspension, to use their senses with greater vivacity and focus on those objects surrounding them and to study passionately all details in all their important curious minutia.

Among the observatons we have made, what might at first seem to be distantly related to such lofty contemplations is simply a summary of reflections suggested by the immediate use of our senses. It is simply the experience of a technician imbued with the varnish of science. Example : In a chemical operation there is always an aggregate to decompose or sometimes the combination of certain bodies to effect. Therefore, one of the first distinctions that laboratory experience provides is to establish the respective nature of aggregation and composition . These are two fundamental terms of chemical language, and they in and of themselves can, by indicating their causes, state all the effects of heat as it is used in treating different bodies. Thus the technician might say: a specific amount of heat will melt gold, dissipate water, calcinate lead, fix saltpeter, decompose tartar, soap, an extract, an animal, etc. And science might say: a specific amount of heat will allow gold's aggregration to weaken, destroys aggregation in water, attacks the composition of lead and saltpeter, excites the reactives in tartar, soap, an extract, an animal, etc. The technician and the scientist also have their own language when talking about the phenomena of dissolving actions. The technician will say: nitric acid that is too strong will not attack silver, but if diluted by a certain amount of water and excited by a certain amount of heat, it will so dissolve it. Science might say: The aggregative union of concentrated acid is greater than its relationship with silver. Water added to the acid weakens its cohesive force and the addition of heat weakens it still further, etc. The technician doesn't generalize, but science will go on to say more generally: in every act of dissolution, the tendency toward dissolution dominates the tendency toward cohesion of the aggregrate.

In all the principles that we've outlined, Metaphysics has proposed nothing that cannot be translated into the technician's simple language, as we have just shown by the prior examples. And the converse is true.

But, if Chemistry contains within itself two different languages, one popular and the other scientific, it nonetheless, distinct from the other natural sciences, has its own way of looking at the world, as we have shown by our preceding exposition and will show by what we have reserved until now to complete our portrayal of Chemistry 's most distinguishing character. And that is that most of the qualities of bodies the Physicist considers as modes are real substances that the Chemist is able to separate out, put back together, or carry over to other bodies. Among these we include color, the principle of inflammability, taste, odor, etc.

What is fire ?, says the Physicist. Is it not a body heated to such a point that it throws off abundant light? Is red-hot iron something different from fire? And what are glowing embers if they are not red-hot wood? (Newton, Opt. Qust. 9 ) However, burning charcoal is no more fire than a soaking sponge is water. For the chemist is able to remove the principle of inflammability, that is fire, as he is able to squeeze water out of the sponge and collect it in another container.

For the Physicist, the color in a colored body is a certain disposition of the body's surface which allows it to reflect particular rays. But for the Chemist, a plant's greenness is inherent to a specific green resinous body, and he is able to remove it from the plant. Clay’s blue coloring is due to a metallic material that he is able to separate out. Even the blue of jasper, which seems so closely united to the fossil substance, has been extracted, according to Becher’s famous experiment.

It's appropriate to observe that in presenting color phenomena Physicists and Chemists make different, but not contractictory statements. The Chemist simply goes one step further. And he can go still further if, when you ask about the make-up of the plant's green resin or the clay’s metallic subtance, he doesn’t fall back on some occult explanation and if he knows about a body, a physical or particular substance to which he can assign as the reason for the color. And indeed, he does know about such a body, phlogiston. In short, when dealing with the properties of compounds and mixtures, the Chemist seeks to find out the principal parts, and he never stops his analysis until he has reached the level of the elements, bodies that he can no longer break down into smaller parts. ( See Phlogiston, Fire, Flammable, Taste, Odor, etc.)

Up to now we have considered Chemistry as the general science of small bodies and as a vast source of knowledge about nature. Its particular application in different areas has produced various branches of Chemistry and different chemical arts. The two branches of Chemistry that have been cultivated the most scientifically and which have thus become the basis of the philosophical chemist's work and the foundation of his experiments are the art of preparing medicines ( see Pharmacy) and the art of working mines and purifying metals on a small or grand scale. ( See Metallurgy, and Docimasie.)

The knowledge that Chemistry has provided for rational medicine might also allow us to consider medicinal theory rising from it as a branch of Chemistry . Medicinal theory is an essential element in the present state of medical theory, whether one rejects it or accepts it on firm facts, because it is founded on particular chemical changes in foods and humours. We are willing, regretfully, to admit that this knowledge is insufficiently widespread and less useful to practical medicine than Boerhaave claimed ( See Element. Chim. Part. 2. usus chimi in medendo). For in Boerhaave's work we often see the dangerous plan to draw truly medicinal truths from knowledge based on physics. ( See Medicine).

We have decided not to talk about Alchemy in this article. ( See Hermetic philosophy).

Making glass and porcelain, the art of enamels, painting on glass (which is not a lost art in spite of the general opinion), pottery, zymotechnics (the art of encouraging fermentation among vegetable subtances, including wine-making), the art of the brewer and the vinegar maker, halotechnics (the art of preparing salts), pyrotechnics the art of making fireworks), the work of tanners and of soapmakers, the art of varnishes and of engraving with acids, dyeing, the preparation of horn, scales and animal hair, the distiller's art, the work of the candy-maker and the drink-mixer, all of these are three branches of pharmacy. The art of breadmaking, panificium , and cooking, etc. are all chemical arts. ( See these particular articles).

Other than the arts that we have just spoken about and which are essentially related to chemical operations, there are others whose basic operations are not chemical but to which Chemistry offers necessary help. Certain chemical products provide the most effective principles of movement, for example in gunpowder, whose use is common knowledge, and steam in the heat pump, etc. Paintings most brilliant and durable colors are gifts of Chemistry , for example.

The strangest and most magical branch of natural magic is the one in which chemical agents operate. Different kinds of phosphorus, oils ignited by acids, exploding powders, violent effervescences, artificial vulcanoes, the production, destruction and sudden changes in the color of certain liquids, unexpected precipitations and coagulations can astonish and amuse people even in our enlightened times, not to mention such apparent fantasies as the philospher's stone, Parecelsus's homunculus, the miracles of palengenesis and all such marvels. ( See Chemical recreations).

Since chemical arts are linked to general Chemistry as to a common trunk, there seem to be two important questions that we must raise. 1. How much can each of these arts be improved and modified by the science of chemistry? and 2. How can the science of chemistry progress using the particular knowledge that arises from working in each of these arts?

As for the first question, it is evident that the best educated and enlightened chemist will direct, reform, and perfect any particular chemical art more or less effectively in proportion to his general knowledge and his science. He will do so, however, on the condition that he has gained the faculty to judge the process as a worker does, that is with feeling and with the experience that come from a hands-on manipulation of the process. It is a fact and easily observable that no scientific means can replace such experience.

The second question requires familiarizing oneself with all of the operations and processes of the chemical arts, following the great chemist Stahl's advice and example. That seems indispensable for the chemist who aspires to expand his understanding of his art. For it is a fascinating and philosophical spectacle to examine the multiple chemical techniques, to consider how they can be used together for different means and how genius is displayed among simple techicians (though technicians call it simply good sense). And these lessons arising from good sense as well as from the technicians' industriousness, facility and experience must not be neglected. In short, one needs to be an artist, a trained and experienced artist, if for no other reason than to be able to execute or direct different processes with the same facility, the same knowledge of resources, the same promptitude which make these operations a game, a pleasure and a captivating spectacle instead of a long painful discouraging exercise during which disheartening obstacles interfere and success is uncertain. All such isolated phenomena, these so-called bizarre operations, this variety of products and singularity of the results of experiments that half-chemists blame on the techniques of chemistry or on unknown properties of the materials they are working with can all be atributed to the artist’s inexperience. They rarely arise with experienced Chemists. It is very rare, and perhaps it never happens, that a true chemist is unable to replicate a product using the same materials. The artist we speak about will never think it sufficient to judge the degree of the heat he uses by thermometers, or the number of drops during a distillation process by a clock with a second hand. Rather, as technicans often say, he will have his thermometer in the tips of his fingers and his clock in his head. In short, he is able to conduct ordinary processes and his daily operations using rough estimations based on his senses, and because of their ease of use, these estimations are preferable when they are sufficient. The chemist learns how to estimate most chemical operations with a great deal of precision. All of the artificial measurements that some would have us use are cumbersome and sometimes impossible, especially thermometers, that are as ridiculous in a working chemist’s apron as they are in a doctor’s pocket when he visits his patients. But the value of the skilled technician is not limited to this advantage. An additional value is that the chemist can draw broader enlightened conclusions from the phenomena that arise during the processes he executes. In such phenomena, the kind that the chancellor Bacon talks about, a chemist can find the springboard for the foundation and development of an important theory. These phenomena might awaken the chemist’s genius, just as the falling apple incited Newton to produce his magnificent system of universal gravitation . Futhermore, it is necessary to sing the praises of experimentation only for those who have never tried their hand at experiments or who have never been able to judge the value of a skilled experienced chemist. For anyone who has lived among the chemist’s furnaces for even six months or who, understandng chemisty, has heard chemists discussing their art, it is clear that the experienced artist is superior to the most profound speculative thinker.

The wisest Chemists agree that an interest in Chemistry is really a madman's passion. And that is because the Chemist must know all these practical processes, must be patient through long tedious experiments and observe them with painstaking care, must cover his expenses, must confront the dangers of the experiments and the temptation to lose sight of everything else. Becher calls Chemists Certum quoddam genus hominum excentricum, heteroclitum, heterogeneum, anomalum ; a man who has a singular obsession, quo sanitas, pecunia, tempus & vita perduntur . But if we accept as given the usefulness of the sciences, and that seems to be the general opinion, then these same difficulties and disadvantages force us to consider those scientists who demonstrate sufficient courage to confront them as citizens who merit our deep gratitude.

Whatever idea we may have of this passion for chemistry, when did it begin to torment men? When do we situate the birth of Chemistry ? Though it would be of value to have such information, it would be difficult to determine.