Chemistry

"At this stage of advance, then, an earth is regarded as differing from an alkali in being insoluble, or nearly insoluble in water; in not being soapy to the touch, and not turning vegetable reds to blue: but as resembling an alkali, in that it combines with and neutralizes an acid; and the product of this neutralization, whether accomplished by an alkali or by an earth, is called a salt."

"We shall not be surprized at the scarcity of pure earthy element, if we consider that the surface of the earth... has been from the beginning of the world exposed to the constant action of the other elements; and that by uninterrupted operations, nature, assisted by fire, air, and water, has gradually disunited the integrant parts of elementary earth, and by combining them in manners and proportions infinitely various with parts of the other elements, has formed the numberless compound bodies, which occupy a certain thickness near the circumference of the globe, probably very small in comparison of the diameter of the earth, but very large with regard to us, whose greatest efforts only extend to a few hundred feet below its surface."

"[T]he earth which makes [shells and scales] of the crustaceous animals... takes the character of that earth which is called calcareous, and which is capable of conversion into quicklime by the action of fire. The earth which has entered into the composition of plants, and even of the bodies of animals, after having been deprived... of... principles of these compounds to which it was united, forms all the argillaceous earths. Some... partake both of the calcareous and of the argillaceous properties, and are called es. Marles have not yet been sufficiently well examined by chemists. They are either a mixture of clay and calcareous earth, or they have been so elaborated by nature as to be transformed into a particular earth, partly calcareous, and partly argillaceous, such as the earth of animal bones seems to be."

"The mercury of a metal... represented its lustre, volatility, fusibility, and malleability; the sulphur of the metal, its colour, combustibility, affinity, and hardness."

"alone is volatilized by the application of any degree less than a red heat; when fully red, or at a heat about that of melting copper, the fixed alkalies begin to be dissipated in dense vapours, but the alkaline earths resist any but the extremest degree of heat which has ever been applied."

"As the earth which forms sands and the common impure vitrifiable stones retains more than the rest the essential properties of elementary earth, notwithstanding the heterogeneous, phlogistic, and other parts with which it is mixed; we cannot easily know whether it has once made a part of some very compound bodies, from the principles of which it has been more perfectly separated than the argillaceous and calcareous earths; or whether it be the primitive earth, which, without having made part of any intimate combination, has only been divided and conveyed by waters, and the parts of which have afterwards reunited, having only contracted a slight union with some phlogistic, metallic, and other matters, with which it is found mixed. This latter supposition appears to me to be the most probable. But very extensive researches in natural history and in chemistry are requisite to determined this question."

"Although the entire mass of our globe be probably formed by an immense heap of elementary, vitrifiable, and even actually vitrified earth, as the illustrious Buffon believes, we do not find upon its surface but a very small quantity of this earth, unaltered, and in its primary state. Perhaps even none of it exists in that state: for, as we have observed, the common vitrifiable stones, which are chiefly formed of it, are very far from the degree of purity of primary elementary earth; and even perfect diamonds, which seem of all these stones to approach the nearest to this purity, seem to have been elaborated by the waters, if we can judge from their regularly crystallized form."

"They all unite with the fixed oils and animal fats, either into a true soap, or into a saponaceous compound. The fixed alkalies unite more perfectly with the oils, and the alkaline are the only true soaps, being soluble in water. The earthy mixtures with oil are indeed strongly combined, but are insoluble in water."

"About 1750 Black went to Edinburgh University to complete his medical studies... The attention of medical men was directed at this time to the action of lime-water as a remedy for stone in the bladder. All the medicines which were of any avail in mitigating the pain attendant on this disease more or less resembled the "caustic ley of the soap-boilers" (...caustic potash or soda). These caustic medicines were mostly prepared by the action of quicklime on some other substance, and quicklime was generally supposed to derive its caustic, or corrosive properties from the fire which was used in changing ordinary into quicklime. When quicklime was heated with "fixed alkalis" (i.e. with potassium or ), it changed these substances into caustic bodies which had a corrosive action on animal matter; hence it was concluded that the quicklime had derived a "power"—or some said had derived "igneous matter"—from the fire, and had communicated this to the fixed alkalis, which thereby acquired the property of corroding animal matter."

"[E]xcepting the purest vitrifiable earth, all the others are mixed with heterogeneous matter. By these remaining heterogeneous matters are the different kinds of earth specified and characterised: and as they all preserve and retain their peculiar character, we ought to conclude from thence, that these extraneous matters are very intimately united. To purify and simplify these mixed earths, so that they shall be assimilated to the purest vitrifiable earth, would be a fine problem. But, probably, this problem is beyond the power of our art. For... the perfect separation of two substances, united together, is exceedingly difficult, this difficulty must greatly increase, when one of the... substances... has a very strong attractive power, as earth has. This is the... reason why we find so small a portion of pure earth amongst the bodies within our reach; and that on the contrary, the globe is covered with so great a quantity of earthy substances differing from each other so much, that we might be inclined to believe them to be bodies essentially different."

"To the earth or alkali, as being the foundation on which the salt is built, by the addition of acid, the name of base was given by Rouelle in 1744."

"The alkalies are extremely soluble in water, s and strontian in considerable quantity, lime, sparingly; magnesia scarcely at all."

"[T]he general tendency of the parts of matter to each other is the grand spring of the universe; that by this power, all combinations, solutions, and, in a word, all the movements and operations of nature are performed: and as... the earthy element possesses this tendency in the greatest degree, we ought to consider earth as being in this sense the most active and powerful of all elements. ...[T]he force with which they adhere together, and which renders them incapable of forming other unions, the extreme hardness, and the insolubility of a mass of pure earth, ought to demonstrate to a true philosopher, that if we suppose the parts of earth so separated ...that they cannot unite ...they must then possess all their force of tendency ...in a state of violent effort, and consequently must tend with extreme force to unite with any parts of matter ...within their reach ...[W]e know compounds in which the primitive integrant parts of the earthy element are only combined with the parts of water, which are incapable of satisfying all their tendency to union. These are the most simple saline substances, such as s and alkalis; and we may judge by the force and vehemence of the action of these solvents, how violent the action of the parts of earth would be, which should be capable of exerting all the attractive force which belongs to them."

"[T]he purest and simplest of all earths ought to be also the heaviest; and accordingly... pure vitrifiable earth is... heavier than calcareous, argillaceous, gypseous, or other earths. ...[N]evertheless ...metals, metallic earths, and several kinds of spars, both calcareous and selenitic, are much heavier than the most compact vitrifiable stones ... [P]arts may be so arranged that void spaces may be left betwixt them, sometimes larger, and sometimes less, therefore a body composed of parts essentially lighter, may yet have a greater specific gravity than another body whose parts are essentially heavier; and this happens in all metals and metallic matters. ...Thus the gravity of metals and of metallic earths and stones ought not to prevent our considering the pure and elementary earthy principle as the heaviest of all natural substances."

"[W]e may consider the properties of elementary earth in the purest vitrifiable stones, and... compare them with the properties of the other elements. Since of these elements water is the most capable of our examination, we shall compare it with the purest vitrifiable earth; observing always, that we consider these elements in their state of aggregation; for we have no method by which their primary integrant parts can be known and considered separately."

"We shall now enumerate the properties usually described as belonging to alkalies, distinguishing how far they are possessed by the three salts and the four earths above enumerated."

"The taste of an alkali is acrid, burning, and nauseous. It acts with so much energy and rapidity on the tongue, as to destroy, if concentrated, the skin of the part which it touches, and hence its extreme causticity. The three alkalies possess this in the highest degree, more rapidly soluble than the earths, and the latter only s, strontian, and lime, exhibit this corrosive taste, magnesia being absolutely insipid."

"I was present at a fine experiment made relatively to this subject. Some diamond powder was mixed with a sufficient quantity of fixed alkali to vitrify another earthy matter, and the mixture exposed to a heat sufficient for the most difficult vitrifications. After the operation, no glass was found in the crucible; but part of the alkali had been dissipated by the violence of the heat, and the diamond powder did not shew any signs of a beginning fusion. Thus we may confider it as an established truth, that the earths and stones called vitrifiable are not essentially and really so; that the fusibility of some of these, by which property they are rendered the fittest earths for vitrification, proceeds from heterogeneous matter with which they are mixed: and that, in general, the whitest, clearest, most transparent and hardest of these stones are also the most refractory and unfusible."

"I do not believe that a pure verifiable earth, as a diamond, can be fused even in the focus of the best burning speculums: but supposing that a sufficient heat might be produced... it would then melt, and would even be reduced to vapors, if the heat were sufficiently violent; and when this heat should cease, it would, when it cooled, fix again, and become such a substance as it was before. The same would happen to vitrifiable earth in these circumstances, which does happen to water rendered fluid, and reduced to vapor by a certain heat, and which is again frozen into solid ice when that heat is removed. The differences, therefore, betwixt these two substances are only... in the degrees; but also these differences are very considerable."

"[T]he name vitrifiable earth... may produce false notions of the nature of these stones."

"[T]he epithet, vitrifiable is given, first, because some stones of this kind are, by means of their heterogeneous matters, capable of fusion and conversion into glass, without addition, and merely by the action of a very violent heat; and secondly, because other stones... require for their perfect fusion and vitrification a less quantity of flux, and a less degree of heat."

"[A]n inference seems deducible, that the elements or the simplest substances which we know are essentially only one and the same matter, and only differ from each other in the quantity and in the form of their primary integrant molecules, which... have a greater or less tendency to unite together..."

"As it is but of little consequence which arrangement be adopted, provided an uniformity be observed, we have throughout the present work restricted the term alkali, to the three antient salts of that name; the two fixed, and soda, and the volatile . Under the appellation alkaline earth, we include the following, s, Strontian, Lime, and Magnesia."

"All the alkalies, except ammonia, are without smell, or nearly so, a particular urinous odor however arises during the solution with heat, of the other alkalies and earths, magnesia excepted."

"In the second place, as all the earths and stones called vitrifiable have, notwithstanding their impurity, more hardness and transparency than others, and are fitter to communicate these good qualities to glass, they are employed preferably to any other earths in the composition, of glass, or artificial crystal. These are the only reasons why this kind of earth has been called vitrifiable. But we ought not from thence to conclude, that the earthy substance [i.e., the earth element or principle] which almost entirely composes them is more fusible and more vitrifiable than other earths: on the contrary... vitrifiable earth, when very pure, is of all earths the least fusible, and the least vitrifiable."

"[A]ll the substances which may reasonably be considered as earthy... possess much greater weight, hardness, fixity, and infusibility, than any other element; for these qualities are insensible, or do dot exist, in the element of fire; they are in an exceedingly small degree in the air, and are more sensible and considerable in water; but are infinitely less than in any thing which can be considered as earth. Hence... the qualities above-mentioned are the distinguishing and characteristic essential properties of the earthy element. But these qualities are not so eminently united in any of those [earthy] substances... as in... vitrifiable earth. ...[T]hen ...this earth is the heaviest, hardest, most fixed, and most infusible, and even the most apyrous of all earths, when it is very pure; and also... the most homogeneous, the most simple, and elementary earth, as we shall prove by a more particular examination of its properties, and by a companion of these with the properties of the other earthy substances."

"We call that vitrifiable earth, the integrant parts of which when united form masses of matter or stones, absolutely white and colorless, much more transparent and hard than any other natural substances, and which suffers no alteration, or even fusion, by the strongest fire which we can apply to it."

"Traces of these ancient conceptions are still to be recognised in the word "quick-silver," that is living silver, a literal translation of argentum vivum. A term "quick-sulphur" (sulphur vivum) was also in use, but it has long since disappeared."

"The salt of the was merely a means of union between the mercury and the sulphur, just as the vital spirit in man unites soul and body. It was doubtless devised to impart a triple form to the idea, in conformity with the method of the theological schoolmen."

"As earth is an element... it deserves an accurate investigation to discover which is the most simple and elementary of all the substances to which the name earth has been applied. ...considering, first, what are the essential properties by which earthy substances differ from other elements, and then by determining that earth to be the most pure and simple, which possesses these properties most eminently and decisively; for ...the more eminently any substance possesses these characteristic properties... the nearer it approaches to this element..."

"Amongst the hard stones called vitrifiable... few... strictly possess all the qualities... mentioned; because in very few... the vitrifiable earth is pure. Most of these stones, as hard pebbles of all kinds, sand, free-stone, s, , rock-crystal, and the stones called precious, are deficient in some... qualities required to constitute the purest vitrifiable earth. Some... are opake, or only semitransparent; others... colored; some... fusible by a great heat; and, lastly, others, although much harder than any other kind of stones, want the last degree of hardness; all which prove that they are mixed with heterogeneous substances, chiefly phlogistic, metallic, or even earthy, of a different kind."

"(whose natural state when uncombined, is that of a gas) magnesia, and probably lime, are incapable of crystallization, the other alkalies and alkaline earths are crystallizable."

"Some of the best philosophical chemists have rather chose to admit different kinds of elementary earths, than to investigate the nature of the most simple and elementary of all. Becker admits three principles, which he calls earths, namely, the vitrifiable, the inflammable, and the mercurial earth..."

"The purest of all the vitrifiable stones is the diamond, which is perfectly white, free from all color or stain, and transparent. This stone is also known to be the hardest of all, is absolutely apyrous, that is, incapable of receiving any alteration by the most violent heat. We, therefore, consider the matter of this stone as the purest, simplest, and most elementary earth that is known. The properties, then, of this stone, and of the other vitrifiable stones which resemble it, may give us notions of the properties of primary, elementary, unchanged earth. In this our opinion is conformable to that of the illustrious Stahl, who indeed admits the three earths of Becker; but, at the same time, corrects the theory of this chemist, by declaring that he only considers the first earth of Becker, or vitrifiable earth, as the proper terrestrial or earthy element."

"[W]e cannot doubt but that earth chiefly differs from the other elements by the powerful tendency which its parts have to each other, and by the force of their cohesion. For its hardness, fusibility, fixity, and even its gravity, are evidently the necessary consequences of this... the cause of the consistence of all solid bodies."

"Of late years, some of the earths (especially s and strontian, which were unknown to antiquity) having been found to possess alkaline properties in no ambiguous degree, these have been by some chemists absolutely associated with the alkalies; by others have received the term alkaline earths, to express this resemblance which in the two above mentioned almost amounts to identity of properties; but in the two others, lime and magnesia, the agreement is only partial."

"Mr. Pott, examining the principal natural earths, divides them into four kinds, the vitrifiable, the , the argillaceous, and the gypseous earths. This able chemist shew the essential properties of these four kinds of earths, without affirming that they are all equally simple, and without even determining which of them he considered as most simple."

"Earth is one of the four simple substances called elements, or primitive principles; because they are indeed the most simple of all those which enter into the combination of compound bodies. We cannot doubt, in particular, that the greatest part of the compounds which we can analyse contain earth as one of their principles; for after art has exhausted all its efforts to decompose them, a fixed and solid matter always remains, upon which no change can be produced; and this is what is generally called earth. It has the solidity, weight, fixity, and other principal properties of the mass of solid matter which forms the globe we inhabit, called also the earth."

"These general considerations are sufficient to convince us, that in nature a substance exists whose properties are different from those of fire, air, water; and which is, like these other substances, one of the elements of compound bodies. But a vague assertion like this does not satisfy chemists. Besides the ascertaining of the exigence of the different substances submitted to their examination, they require to know the properties of these substances in their greatest degree of purity and simplicity; but they have found much difficulty and uncertainty in investigating the essential properties of the purest and simplest terrestrial element."

"[Paracelsus] arranged the several parts of man, his own universal elements, and the Aristotelian elements in triplets, thus :—"

"[T]he writings and labours of the alchemists were both extensive and important. ...[T]heir studies, although misdirected, were not... haphazard. The alchemists had a definite, and... logical, system of philosophy... [T]hey recognised—(1) the unity of matter; (2) the three principles—philosophical mercury, sulphur, and salt; (3) the four elements—fire, air, water, and earth; and (4) the seven metals—gold, silver, mercury, copper, , tin, and ."

"What made silica so interesting was that... it did not seem to follow the established rules of chemical combination. In Smithson's time, chemical combination was... an acid combining with an alkali to produce a stable, neutral... "." Acids did not combine chemically with each other, nor did alkalis... [A] substance... found to contain an alkali... must also contain an acid—and vice versa. Bergman's description of the compounds containing earths as... "natural compositions of acids" meant... the other component must be alkaline—which the earths all seemed to be, except for silica."

"Earth is not found so pure as the other elements, fire, air, and water, which, though not entirely free from mixture, are however so pure, that we may certainly and easily discover their fundamental properties. These properties of each of these pure elements are so well ascertained, and so evident, that nobody has yet attempted to distinguish different kinds of fire, air, or water, notwithstanding the differences which may arise from the heterogeneous substances with which they are almost always mixed."

"By 3000 BCE the Sumerians, perhaps while heating copper to make it more malleable, had discovered that more copper could be retrieved from the fire if the metal were heated with certain types of dirt and stones—that is, certain earths. These earths were the metal s, and the process they discovered, ', reduced metal salts to pure metal by the action of in the fire. The process of changing metal salts into pure metal is known as reduction because the metal without the accompanying oxygen, , or of the salt weighs less than the ore. Eventually metal workers learned to distinguish various metal-bearing ores by color, texture, weight, flame color, or smell when heated (such as garlic odor of ores) and they could produce a desired material on demand."

"Pliny recorded processes involving metals, salts, , glass, mortar, soot, ash, and a large variety of s, earths, and stones. He describes the manufacture of charcoal; the enrichment of the soil with lime, ashes, and manure; the production of wines and ; varieties of s; plants of medicinal or chemical interest; and types of , gems and precious stones. He discusses some simple chemical reactions... and a crude indicator paper... of strips soaked in an extract of oak galls that changed color when dipped in solutions of blue vitriol... contaminated with ."

"But we cannot say the same of earth; for a considerable number of substances are called earths, because they possess the principal properties of the terrestrial element: but these substances, when examined more particularly, are always found to differ from each other so much in other respects, and to be so difficultly purifiable from heterogeneous matter, that we have not ascertained whether only one simple and elementary earth, or several ones essentially different, although equally simple, exist."

"He concludes... that the Paracelsian elements—their "salt," "sulphur," and "mercury"—are not the first and most simple principles of bodies; but that these consist, at most, of concretions of corpuscles or particles more simple than they, and possessing the radical and universal properties of volume, shape, and motion."

"The original matter, or ', was called by various names—universal substance, seed, chaos. Although matter changes its form, it cannot be destroyed. ...In its nature the ' was assumed to be a liquid, containing everything in posse, but nothing in esse."

"The Earths are white, inodorous, tasteless, and uninflammable substances—non-conductors of electricity, insoluble in water, but soluble in one or more of the acids. Sp. gr. compared to that of water, not exceeding five to one. They are six in number; viz. silica, alumine, , gluttine, augustine, ytria; the consideration of which falls under their alphabetical order."

"The alkalis are very soluble in water; these solutions neutralise acids forming salts, and also precipitate most of the heavy metals from their solutions in the form of oxides or hydrated oxides; aqueous solutions of the alkalis act corrosively on animal and vegetable substances, and also alter the tint of many colouring matters."