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The Fifth Subject of the Physics, consisting of two discourses upon meteorological phenomena. This subject comprises the secondary causes of the inanimate creation such as minerals, meteorological phenomena and the like.
The, First Discourse, upon those things which occur upon the earth.
Section 1. Upon Mountains.
We shall begin by establishing the condition of the formation of mountains and the opinions that must be known upon this subject. The first [topic] is the condition of the formation of stone, the second is the condition of the formation of stones great in bulk or in number, and the third is the condition of the formation of cliffs and heights.
We say that, for the most part, pure earth does not petrify, because the predominance of dryness over [i.e. in] the earth endows it not with coherence but rather with crumbliness. In general, stone is formed in two ways only (a) through the hardening of clay, and (b) by the congelation [of waters]. Many stones in fact, are formed from a substance in which earthiness predominates, and many of them are derived from a substance in which aquosity predominates. Often a clay dries and is changed at first into something intermediate between stone and clay, viz. a soft stone, and afterwards is changed into stone [proper]. The clay which most readily lends itself to this is that which is agglutinative, for if it is not agglutinative it usually crumbles before it petrifies. In my childhood I saw, on the bank of the Oxus, deposits of the clay which people use for washing their heads; subsequently I observed that it had become converted into a soft stone, and that was in the space of approximately 23 years.
Stone has also been formed from flowing water in two ways (a) by the congelation of the water as it falls drop by drop or as a whole during its flow, and (b) by the deposition from it, in its course, of something which adheres to the surface of its bed and [then] petrifies. Running waters have been observed, part of which, dripping upon a certain spot, solidifies into stone or pebbles of various colours, and dripping water has been seen which, though not congealing normally, yet immediately petrifies when it falls upon stony ground near its channel. We know therefore that in that ground there must be a congealing petrifying virtue which converts the liquid to the solid. Thus the bases of the formation of stone are [either] a soft clayey substance or a substance in which aquosity predominates. Congelation of the latter variety must he caused by a mineralizing, solidifying virtue, or earthiness must have become predominant in it in the same way in which salt is coagulated, i.e. earthiness becomes predominant in it by reason of its [peculiar] virtue and not of its amount. If indeed the earthy quality is not like that in salt, hut is of a different kind, nevertheless the two must be similar in that they are transformed by heat, and in that the advent of heat coagulates them. Or it may be that the virtue is yet another, unknown to us. Alternatively, the converse may be true that its earthiness has prevailed merely by a cold dry virtue.
In short, it is in the nature of water, as you know, to become transformed into earth through a predominating earthy virtue; you know, too, that it is in the nature of earth to become transformed into water through a predominating aqueous virtue. In this connection, there is a substance used by those; folk who have lost their way amid their artful contrivances which, when they are so minded, they call Virgin’s Milk; it is compounded of two waters which coagulate into a hard solid.1 This is an indication of the truth of [what I have said above]. They have also many things which they use in liquefaction and coagulation which bear witness to the soundness of these judgments.
Stones are formed, then, either by the hardening of agglutinative clay in the sun, or by the coagulation of aquosity by a desiccative earthy quality, or by reason of a desiccation through heat. If what is said concerning the petrifaction of animals and plants is true, the cause of this [phenomenon] is a powerful mineralizing and petrifying virtue which arises in certain stony spots, or emanates suddenly from the earth during earthquakes and subsidences, and petrifies whatever comes into contact with it. As a matter of fact, the petrifaction of the bodies of animals and plants is not more extraordinary than the transformation of waters.
It is not impossible for compounds to be converted into a single element if the virtue of the latter gets the mastery over them, for each of the elements they contain may be converted into that element. For this reason anything which falls into salt-pans is converted into salt, while objects which fall into the fire are converted into fire. As for the swiftness or slowness of the conversion, that is a matter which necessarily varies according to the variation in the strength of the virtues; if they are very violent they perform the conversion in a short time. In Arabia there is a tract of volcanic earth which turns to its own colour everyone who lives there and every object which falls upon it. I myself have seen a loaf of bread in the shape of a raghîf2—baked, thin in the middle, and showing the marks of a bite which had petrified but still retained its original colour, and on one of its sides was the impression of the lines in the oven. I found it thrown away on a mountain near Jâjarm, a town of Khurâsân, and I carried it about with me for a time. These things appear strange only on account of their infrequent occurrence; their natural causes, however, are manifest and well-known.
Certain varieties of stone are formed during the extinction of fire, and frequently ferreous and stony bodies originate during thunderstorms, by reason of the accidental qualities of coldness and dryness which fieriness acquires when it is extinguished. In the country of the Turks there fell, amid thunder and lightning, coppery bodies in the shape of arrowheads with a projection turned back towards the top. A similar one fell in Jil and Dailam,3 and when it fell it penetrated into the earth. The substance of all these was coppery and dry. I myself undertook, in Khwarazm,4 the difficult task of fusing a head of that kind, but it would not melt; a greenish fume continued to come off from it until at length an ashy substance remained ... .
This, then, is one kind of way in which stone is formed. A trustworthy man from among the Shaikhs of the kingdom of Işfahân, Abû Manşûr Hormuz Diyâr ibn Mashakzâr, one in close relation with the illustrious Amir Abû Ja’far Muhammad ibn Dushinanzâr (may God have mercy upon him!), told me that there fell from the sky, in the mountains of Ţabaristân, an object the fall of which resembled the fall of the above-mentioned mass of iron, except that in this case it was a huge stone. This completes the discourse upon the formation of stones.
As for the formation of large stones, this may occur all at once, by intense heat acting suddenly upon a large mass of clay, or little by little with the passage of time.
The formation of heights is brought about by (a) an essential cause and (b) an accidental cause. The essential cause [is concerned] when, as in many violent earthquakes, the wind which produces the earthquake raises a part of the ground and a height is suddenly formed. In the case of the accidental cause, certain parts of the ground become hollowed out while others do not, by the erosive action of winds and Hoods which carry away one part of the earth but not another. That part which suffers the action of the current becomes hollowed out, while that upon which the current does not flow is left as a height. The current continues to penetrate the first-formed hollow until at length it forms a deep valley, while the area from which it has turned aside is left as an eminence. This may be taken as what is definitely known about mountains and the hollows and passes between them.
Very often both water and wind would be ineffectual except for the fact that the earth is not uniform, some parts of it being soft and others stony. The soft, earthy parts become hollowed out and the stony parts are left behind as elevations. With the passage of time, the channel is excavated and widened more and more, while the raised portion is left, becoming relatively higher and higher as more earth is hollowed out from [beside] it. These, then, are the principal causes of the three changes [mentioned at the beginning of the fasl, viz. the formation of stone, the formation of stones great in bulk or in number, and the formation of cliffs and heights].
Mountains have been formed by one [on other] of the causes of the formation of stone, most probably from agglutinative clay which slowly dried and petrified during ages of which we have no record. It seems likely that this habitable world was in former days uninhabitable and, indeed, submerged beneath the ocean. Then, becoming exposed little by little, it petrified in the course of ages the limits of which history has not preserved; or it may have petrified beneath the waters by reason of the intense heat confined under the sea. The more probable [of these two possibilities] is that petrifaction occurred after the earth had been exposed, and that the condition of the clay, which would then be agglutinative, assisted the petrifaction.
It is for this reason [i.e. that the earth was once covered by the sea] that in many stones, when they are broken, are found parts of aquatic animals, such as shells, etc.
It is not impossible that the mineralizing virtue was generated there [i.e. in the petrifying clay] and aided the process, while the waters also may have petrified. Most probably, mountains were formed by all these causes.
The abundance of stone in them is due to the abundance, in the sea, of clay which was afterwards exposed. Their elevation is due to the excavating action of floods and winds on the matter which lies between them, for if you examine the majority of mountains you will see that the hollows between them have been caused by floods. This action, however, took place and was completed only in the course of many ages, so that the trace of each individual flood has not been left; only that of the most recent of them can be seen.
At the present time, most mountains are in the stage of decay and disintegration, for they grew and were formed only during their gradual exposure by the waters. Now, however, they are in the grip of disintegration, except those of them which God wills should increase through the petrifaction of waters upon them, or through Hoods which bring them a large quantity of clay that petrifies on them. I have, I believe, heard that this has been observed on certain mountains. As for [the similar phenomenon] which I witnessed upon the banks of the Oxus, that place cannot properly be called a mountain.
Of the land which was exposed by the retreat of the waters, those parts which were of harder clay or more strongly petrified or of greater bulk than the rest remained as elevations and heights when the other parts had been carried away.
As for the veins of clay that are found in mountains, it is possible that these were formed not from the main substance which has undergone petrifaction, but from debris of the mountains that turned into dust and filled the valleys and ravines. It then became moistened by streams which flowed upon it, and was covered by the layers of stone forming the mountains, or interlaid with the good clay of the latter. It is possible also that the ancient clay of the sea was not uniform in substance, and that in succession some of it petrified thoroughly, while some did not petrify at all, and some was converted only into a soft stone through a certain quality predominant in it or by reason of some one of innumerable other causes.
It is also possible that the sea may have happened to flow little by little over laud consisting of both plain and mountain and then have ebbed away from it; and so it came to pass that the plain was turned into clay without the same befalling the mountain. Once converted into clay, it was in a fit state to undergo petrifaction when it became exposed, and its petrifaction would be complete and strong. When exposure of the matter which was petrifying took place, it must frequently have happened that the old petrified portions [i.e. the mountains] were in a state fit for disintegration, and so would suffer the converse of what was happening to the earth. That is, they became moist and soft and turned into dust again, which itself is in a fit state for petrifaction. For example, when you soak a brick, some earth and some clay in water, and then expose each of them to the fire, the soaking will increase the tendency of the brick to be disintegrated again by the fire, and will also increase the tendency of the earth and the clay to petrify strongly.
It is possible that each time the land was exposed by the ebbing of the sea a layer was left, since we see that, some mountains appear to have been piled up layer by layer, and it, is therefore likely that the clay from which they were formed was itself at one time arranged in layers. One layer was formed first, then, at a different period, a further layer was formed and piled [upon the first, and so on]. Over each layer there spread a substance of different material, which formed a partition between it and the next layer; but when petrifaction took place something occurred to the partition which caused it to break up and disintegrate from between the layers.
As to the bottom of the sea, its clay is either sedimentary or primaeval, the latter not being sedimentary. It is probable that the sedimentary clay was formed by the disintegration of the strata of mountains. Such is the formation of mountains.
...
The Formation of Minerals
The time has now arrived for us to give an account of the properties of mineral substances. We say, therefore, that mineral bodies may be roughly divided into four groups, viz. stones, fusible substances, sulphurs and salts. This is for the following reason: some of the mineral bodies are weak in substance and feeble in composition and union, while others are strong in substance. Of the latter, some are malleable and some are not malleable. Of [the former, i.e.] those which are feeble in substance, some have the nature of salt and are easily dissolved by moisture, such as alum, vitriol, sal-ammoniac and qalqand,5 while others are oily in nature and are not easily dissolved by moisture alone, such as sulphur and arsenic [sulphides].
Mercury is included in the second group, inasmuch as it is the essential constituent element of malleable bodies or at least is similar to it.
All malleable bodies are fusible, though sometimes only indirectly, whereas most non-malleable substances cannot be fused in the orthodox way or even softened except with difficulty.
The material of malleable bodies is an aqueous substance united so firmly with an earthy substance that the two cannot be separated from one another. This aqueous substance has been congealed by cold after heat has acted upon it and matured it. Included in the group [of malleable bodies], however, are some which are still quick and have not congealed on account of their oily nature; for this reason, too, they are malleable.
As regards the stony kinds of naturally-occurring mineral substances, the material of which they are made is also aqueous, but they have not been congealed by cold alone. Their congelation has, on the contrary, been brought about by dryness which has converted the aquosity into terrestreity. They do not contain a quick, oily humidity and so are non-malleable; and because their solidification has been caused mainly by dryness, the majority of them are infusible unless they are subjected to some physical process which facilitates fusion.
Alum and sal-ammoniac belong to the family of salts, though sal-ammoniac possesses a fieriness in excess of its earthiness, and may therefore be completely sublimed. It consists of water combined with a hot smoke, very tenuous and excessively fiery, and has been coagulated by dryness.
In the case of the sulphurs, their aquosity has suffered a vigorous leavening with earthiness and aeriness under the leavening action of heat, so far as to become oily in nature; subsequently it has been solidified by cold.
The vitriols are composed of a salty principle, a sulphureous principle and stone, and contain the virtue of some of the fusible bodies [metals]. Those of them which resemble qalqand and qalqatâr are formed from crude vitriols by partial solution, the salty constituent alone dissolving, together with whatever sulphureity there may be. Coagulation follows, after a virtue has been acquired from a metallic ore. Those that acquire the virtue of iron become red or yellow, e.g. qalqaldr, while those which acquire the virtue of copper become green. It is for this reason that they are so easily prepared by means of this art.
Mercury seems to be water with which a very tenuous and sulphureous earth has become so intimately mixed that no surface can be separated from it without something of that dryness covering it. Consequently it does not cling to the hand or confine itself closely to the shape of the vessel which contains it, but remains in no particular shape unless it is subdued.6 Its whiteness is derived from the purity of that aquosity, from the whiteness of the subtle earthiness which it contains, and from the admixture of aeriness with it.
A property of mercury is that it is solidified by the vapours of sulphureous substances; it is therefore quickly solidified by lead or by sulphur vapour. It seems, moreover, that mercury, or something resembling it, is the essential constituent element of all the fusible bodies, for all of them are converted into mercury on fusion. Most of them, however, fuse only at a very high temperature, so that their mercury appears red. In the case of lead, an onlooker does not doubt that this is mercury, since it melts at a lower temperature, but if during the fusion it is heated to the high temperature [mentioned above], its colour becomes the same as that of the other fusible bodies, i.e. fiery-red.
It is for this reason, viz. that it is of their substance, that mercury so easily clings to all these bodies. But these bodies differ in their composition from it by reason of variation in the mercury itself—or whatever it is that plays the same part—and also through variation in what is mixed with it and causes its solidification.
If the mercury be pure, and if it be commingled with and solidified by the virtue of a white sulphur which neither induces combustion nor is impure, but on the contrary is more excellent than that prepared by the adepts, then the product is silver. If the sulphur besides being pure is even better than that just described, and whiter, and if in addition it possesses a tinctorial, fiery, subtle and non-combustive virtue—in short, if it is superior to that which the adepts can prepare—it will solidify the mercury into gold.
Then again, if the mercury is of good substance, but the sulphur which solidifies it is impure, possessing on the contrary a property of combustibility, the product will be copper. If the mercury is corrupt, unclean, lacking in cohesion and earthy, and the sulphur is also impure, the product will be iron. As for tin, it is probable that its mercury is good, but that its sulphur is corrupt; and that the commingling [of the two] is not firm, but has taken place, so to speak, layer by layer, for which reason the metal shrieks. Lead, it seems likely, is formed from an impure, heavy, clayey mercury and an impure, fetid and feeble sulphur, for which reason its solidification has not been thorough.
There is little doubt that, by alchemy, the adepts can contrive solidifications in which the qualities of the solidifications of mercury by the sulphurs are perceptible to the senses, though the alchemical qualities are not identical in principle or in perfection with the natural ones, but merely bear a resemblance and relationship to them. Hence the belief arises that their natural formation takes place in this way or in some similar way, though alchemy falls short of nature in this respect and, in spite of great effort, cannot overtake her.
As to the claims of the alchemists, it must be clearly understood that it is not in their power to bring about any true change of species. They can, however, produce excellent imitations, dyeing the red [metal] white so that it closely resembles silver, or dyeing it yellow so that it closely resembles gold. They can, too, dye the white [metal] with any colour they desire, until it bears a close resemblance to gold or copper; and they can free the leads from most of their defects and impurities. Yet in these [dyed metals] the essential nature remains unchanged; they are merely so dominated by induced qualities that errors may be made concerning them, just as it happens that men are deceived by salt, qalqand, sal-ammoniac, etc.
I do not deny that such a degree of accuracy may be reached as to deceive even the shrewdest, but the possibility of eliminating or imparting the specific difference has never been clear to me. On the contrary, I regard it as impossible, since there is no way of splitting up one combination into another. Those properties which are perceived by the senses are probably not the differences which separate the metals into species, but rather accidents or consequences, the specific differences being unknown. And if a thing is unknown, how is it possible for anyone to endeavour to produce it or to destroy it?
As for the removal or imparting of the dyes or such accidental properties as odours and densities, these are things which one ought not to persist in denying merely because of lack of knowledge concerning them, for there is no proof whatever of their impossibility.
It is likely that the proportion of the elements which enter into the composition of the essential substance of each of the metals enumerated is different from that of any other. If this is so, one metal cannot be converted into another unless the compound is broken up and converted into the composition of that into which its transformation is desired. This, however, cannot be effected by fusion, which maintains the union and merely causes the introduction of some foreign substance or virtue.
There is much I could have said upon this subject if I had so desired, but there is little profit in it nor is there any necessity for it here.
Translated by E. J. Holmyard and D. C. Mandeville
Reading and Discussion Questions
1.What observational evidence does Ibn Sina (Avicenna) provide in describing how geological formations come to be? What does his account of how mountains are formed suggest about his opinion on the age of the earth?
2.In what ways is Ibn Sina building on Aristotle’s theory of terrestrial matter as described in Meteorology? What other properties of matter is he trying to explain?
3.What reason does Ibn Sina offer for believing that dry parts of the earth, including the mountains, were once covered by sea?
1A thrust at the alchemists.
2A round cake of bread.
3Two Persian provinces on the south-west shores of the Caspian Sea.
4Modern Khiva.
5Green vitriol, FeSO4.
6Probably the meaning is: unless it is amalgamated or sublimed or fixed, i.e. converted into a compound.