Aristotle · a new plain-English translation from the original language
1| [section 2] For in these there are three things: clay, from which shell-like brick comes to be; second, water, which is what solidifies shell-like things; third, fire, which draws its parts together, until through it its generation is completed. The manifestation, then, of the whole unification of these things comes from fire, because there is a certain porousness present in shell-like things in their own several parts. [section 3] And whenever fire mixes these together, the matter of the moisture is brought to completion, and the parts of the clay are cemented together, and dryness advances into the place of the moisture. And because of this dominance, concoction follows in every animal and plant and in metals. For concoction occurs wherever moisture and heat proceed together toward their own proper limit. [section 4] This is evident in the concoction of stone and of metals; but in the animal and the plant it is not so, because their parts are not compacted together into one as they are in stones, and because from these a certain flowing-off proceeds, whereas from stones and metals no flowing-off, or any kind of sweat, issues. [section 5] For their parts are not porous, and hence nothing goes out from them, as excretions go out from the animal and the plant, nor does any other outflow occur from porousness. For where there is no porousness, nothing whatever goes out from it. For this reason it is solid, and it is not its nature to grow into anything.
2| [section 6] For what is naturally suited to grow needs a place in which it may spread out and be bounded. But stones and shells and things of this kind are always in the same state; they neither grow nor extend. Again, in plants there is a second kind of motion, namely attraction, which is a capacity drawing moisture up from the earth. [section 7] And in this attraction there is a motion which arrives at a place, and concoction is in a way brought to completion; and because of this, for the most part small plants are generated in the space of a single hour of a single day. This is not so in animals; for in animals the matter exists by itself and is divided up. Nor does concoction occur in them except above all in use. [section 8] The matter of the plant, however, is close to this, and for this reason its generation is quicker. And that which is finer in it, rather than the dense, is what is generated and grows. For the dense requires capacities of many kinds, both because of the difference of its own proper shape and because of the length of its parts in relation to one another. [section 9] And hence the generation of the plant, too, is quicker, on account of the fineness of one part relative to another, and its completion is faster. The parts of plants are for the most part porous, because their heat draws the moisture toward the extremities of the plants. And the nourishing matter is dispersed into all their parts; and what is in excess is poured out.
3| [section 10] Just as in bathhouses heat draws up moisture and turns it into vapor, and this vapor, being made light, when it becomes excessive changes into droplets, so too in animals and in plants the residues rise from the lower parts to the upper, and descend from the upper parts to the lower. In the same way the rivers that run beneath the earth are generated from the mountains. For their matter is the rains; and when the waters increase and are confined within a narrow space, an excessive vapor is produced from them, which, because of the pressure within, splits the earth; and so springs and rivers appear that were not visible before but happened to be hidden away. [section 1] We have set out the causes of the generation of springs and rivers in our book on meteorology, in which we also spoke about earthquakes—that these often reveal springs and rivers that were not visible before, as when the earth is split open by the rising vapor. And we often find that springs and rivers are joined together when an earthquake occurs. [section 2] But this does not happen to the plant, because air is present in the looseness of its parts, and here too is a sign of this: an earthquake does not naturally occur in sandy places, but in places that are dense and hard, of the sort found where there is water and mountains.
4| [section 3] For indeed an earthquake occurs in these places because the water is solid and the stones are solid; but it belongs to the nature of hot, dry air to rise on account of its lightness. So when the parts of this air come together and gain the upper hand, they press together the place, and from this a violent exhalation issues out of it. [section 4] But if the place were loose, the exhalation would not issue out in this way, but as happens in the case of sand. For an exhalation issues out from there too, but little by little; and because of this no earthquake occurs. In general, then, in no solid body does this happen—I mean the air issuing out little by little. [section 5] For when the parts of this air are gathered together they are able to split the earth, and this is the cause of earthquake in solid bodies. In the parts of plants and animals no earthquake occurs, but in all other things, and most often in shelled things and in glass and the rest of the metals. [section 6] For in whatever body there is much looseness, it is customary for the exhalation to rise as well; for the air lightens it. And we often see this when we throw gold or something else heavy into water, and it sinks at once; and again when we throw in a piece of wood that is loose-textured or small, it floats and does not sink.
5| [section 7] Hence it is not on account of leaves that a piece of wood which is often submerged fails to sink, nor on account of what lies beneath it being heavy, but because the one is solid and dense, and the other loose; and what is loose does not sink at all. [section 8] Ebony and things similar to it do sink, because in these the looseness is slight, and there is no air in them able to lighten them. They sink because their parts are extremely dense and solid. But all oil and all leaves float on top of water. [section 9] And this we can now demonstrate. For we know that there is moisture and heat in these things, and it is the nature of the moist to be joined to the parts of water; and heat causes the moist to be drawn upward, just as follows in the season of spring. And it is also the nature of water to lift everything up to its own surface, as far as the surface of the air, so that it makes it rise. [section 10] But water does not go beyond its own surface; for the whole surface of water is one together with the surface of air. And because of this oil also rises up above water. There are also certain stones that float on top of water, because of the void alone in them being greater than the parts within them, and because the space occupied by air is greater than the space occupied by the body of earth.
6| [section 11] For it is the nature of water to stand above earth, and it is the nature of air to stand above water. The nature, then, of the air enclosed within the stone rises up above the water, and joins itself to the whole mass of air; for each thing draws to itself what is akin and like to it, and the nature of the part follows along with the whole to which it is joined. [section 12] If, then, there is some light piece of pumice, half of it will sink in the water, while the rest will float, because in it the air is greater than the remaining body of the stone. Because of this all trees are heavier than such stones. Stones that occur in waters arise from the violent clashing together of waters. [section 13] For first foam is produced, then it congeals in this way like a kind of fatty milk; and when the water is rubbed against the sand, the sand somehow gathers together the fatty substance of the foam, and the dryness of the sea, together with excessive saltiness, dries it out; and so the parts of the sand are drawn together, and over the length of time they become stones. [section 14] The proof that the sea produces sand by itself is this: not all earth is sweet; so when some water stands in it, the air is prevented from altering it,
7| [section 15] and further, as the enclosed water lingers in the place, since the air cannot make it like itself (for the earthy parts, which are salty, prevail within the water itself), it is necessary that, warmed further, little by little it makes the two into an inherent clay. [section 16] But this cannot happen in sweet waters because of their sweetness and their fineness, but it happens in salty waters, because in these the dryness of the earth prevails, and either it changes the water into its own form, or it does this near itself, and each of the two is altered. [section 17] And the hardness of the earth, hardening the residue of the water in accordance with the power of its own compaction, divides the clay into its own small parts; and because of this the earth that lies near the sea becomes sandy. So too the plains, which have nothing to cover them from the sun, are also far removed from sweet water. [section 18] For the sun dries out the sweet parts of the moisture, and what remains is what belongs to the kind of earth. And because the sun lingers in this uncovered place, the parts of the clay are separated from one another, and from this sand is produced. A sign of this is that in such a place, if we dig deep, we find inherent clay, and this is the root of sand.
8| [section 19] Sand is not produced except accidentally. This happens because there is a lingering of the sun's motion, as we said, and a remoteness from sweet water. In the same way one must think about the saltiness of the waters of the sea. For the root of all waters is sweet, and saltiness does not come about in it otherwise than in the manner stated. [section 20] And this is a perceptible sign that earth lies beneath water, and water lies above of necessity and by nature. And from this it has come about, more properly, that water is an element rather than earth. Some have held that the element is that which is the most abundant of all waters; and the water of the sea is the most abundant, and for this reason it has been judged to be the element of all waters. [section 21] Water by nature stands above earth and is finer than it. And because of this we have shown that sweet water is altogether lighter than salty water. But let us also take, as an example, two equal vessels, and let us put in them sweet water and salty water. After this let us take an egg, and let us put it in the sweet water, and it will sink at once.
9| [section 22] After this let us set it also in salt water, and it will float on top and rise above the surface of such water, because the parts of this water are not separated apart as the parts of sweet water are. For the parts of the latter, because of their thinness, are not able to bear weight, while the parts of the former, because of their thickness, are able to; and this is why what is placed on it does not sink down. [section 23] In this way, naturally, in the Dead Sea no animal either sinks or is born; for dryness rules in it, and in everything that is close to the character of earth. It is apparent, then, from this that thick water lies below what is not thick. For the thick is of the genus of earth, while the thin and rarefied is of the genus of air. [section 24] And for this reason sweet water surpasses all waters; for it exists further from earth. We already know, then, that the water furthest from earth is the natural one. And we have shown that sweet water lies above sea water. And that this is natural has become clear and necessary by the sign stated.
10| [section 25] Salt is generated in standing waters, in which the sweet becomes salty. But the saltiness of earth exceeds that saltiness. For in the former, air remains enclosed, but not in the latter. And for this reason that body is not of earth, sharing in some sweetness in every way, even if this kind is from water, which comes out of the earth itself like sweat. [section 1] In addition to these things we ought to know that plants and species too do not exist except from composition, and not from simple matter, but just as saltness comes from the water of the sea and from the substance of the sand. [section 2] For the vapors that rise, when they are compacted together, are able to comprehend together the cause of the existence of plants; for air falls down from there, and moistens the place with dew, and from it, through the power of the stars, the forms of seeds come forth. [section 3] Water is the necessary matter, even if there is a differentia within the genus of water. For what rises up is nothing other than sweet water; but the salty is heavy, and does not rise up together with the sweet. What surpasses this in rising is the thinner part of the water.
11| [section 4] This, then, if it is drawn up by the air, is thinned and rises further, and from this springs and rivers come to be in the mountains, and run for a great distance. And a sign of this is the blood that rises to the brain. For just as something rises from foods together with the vapor, so too into all waters, [section 5] For indeed something of the salty water also rises up together with that which the heat has dried out, into the form of air, which lies exactly above all sweet water and salt water. We have often found an example of this account in bathhouses. [section 6] For when heat takes hold of salt water, it thins its parts, and a vapor rises, which was in the floor of the bathhouse, and the dense parts of the saltiness withdraw together with the natural moisture (for they are not of the genus of air), so as to follow the vapor, which proceeds upward one after another. [section 7] When, then, many of them have proceeded, the ceiling is pressed down, and from this the sweet water is gathered together and compacted and turns and drips down. And so in all salt bathhouses there is sweet water. Therefore the plants that grow in salty waters ought not to have abundance, because of the dryness.
12| [section 8] For indeed a plant needs two things, I mean matter and place, fitted to its own nature. When, then, these two things are present together, the plant advances. But when we find matter that is furthest from good temperament, it is in vain; for being in a place that is not well-tempered is an obstacle to existing. [section 9] Again, in general we do not find a plant in snow, except that sometimes we see a plant appearing in it, and certain animals, and especially worms. For these are generated in the snow, and mullein, and all bitter plants. But snow does not seek to bring this about, unless some cause also is joined together in it. [section 10] And this is that snow sometimes comes down like smoke, and wind compacts it together and air constricts it. Yet a certain rarefaction also occurs in its parts; for in these a warm part of air is retained, and from it also a putrefied water remains. [section 11] When, then, the enclosed air becomes of greater breadth and the sun is present, the compressed air in the snow is broken apart, and the putrefied moisture appears, which also compacts together with the heat of the sun; and thus certain plants grow,
13| [section 12] But if the place is covered over, plants do not come to be in it except without leaves; for the good temperament of the earth, which is akin to it, has withdrawn from it. Whence flowers and leaves mixed in with small plants are found in places purely tempered through air and water; but in other places not of this kind the flowers and leaves of the plants that occur in snow are scarce. [section 13] Likewise in many places that are salty and dry, for the most part no plant appears. For these places are far from good temperament; for the earth is diminished, from which moisture and heat are far away, which come about through sweet water. And sometimes sweet earth becomes dead, and then plants are not quickly generated in it. [section 14] But in hot places, where there is sweet water and much heat, digestion comes about beforehand from two parts, from the disposition of the place together also with the air present in it. And the digestion of the air comes from the heat of the sun in that place. From this, mountains too draw up moisture, and the heat of the air also helps them.
14| [section 15] Digestion also hastens this along; and for this reason plants for the most part grow on mountains. But in sands, as we said before, saltiness prevails, and there remain in the parts of the sand rarefactions similar to one another. [section 16] The sun, then, does not have the power to complete and secure continuity of substance in them. For this reason plants for the most part do not come to be in them; and if they do come to be, they are not according to their own distinct species, but according to species similar to one another. [section 1] The plants that are generated on the surface of water are generated in no other way than through the thickness of the water. For when heat touches water, which above has no way of being moved, then something resembling a cloud comes forth upon it, and holds a little air, and such moisture putrefies, and the heat, which extends over the face of the water, draws it up, and from this a plant comes to be. [section 2] It has no root, because a root is fixed in the parts of the earth, having divided parts. Again, it has no leaves either, because it is far from good temperament, and its parts also are not compacted together. But this plant is generated something like a resemblance of leaves, and is called "feather-plant."
15| [section 3] As for the remaining plants that are in the earth, since the parts of the earth are compacted together, the parts of these too are necessarily of this kind. At any rate, the plants that are compacted from the earth come to be from decompositions in a moist and smoky place. [section 4] For the decompositions hold air within them; and when the rains and winds increase, the sun makes them show themselves, and it hastens them to dry out and be compacted, and the dryness of the earth produces their roots; and from this come plants, mushrooms, truffles, and things of this kind. [section 5] All these things come to be, reasonably, in warm places, since the heat concocts the water in the inner parts of the earth, the sun holds it there, and an exhalation comes to be, and from this the alteration into a plant occurs. Likewise in all places that are for the most part warm, the completion of the plant is fulfilled. [section 6] Cold places, even if they too sometimes produce the same result, do so from the opposite cause. For the cold air presses the warm air down below and compacts its parts together, and the place undergoes a kind of boiling together with the moisture present in it; when, then, the excess moisture has dried out, the place splits open, and plants come out of it.
16| [section 7] In sweet-water places, where the water does not happen to separate out for long, whenever the air enclosed in the earth dries out and the moisture of the water compacts together, and this same air remains within the water, plants come out — such as the medicinal water-lily, and many other species of small plants, which are indeed generated in this manner. [section 8] But they are not far-extending, because their roots lie shallow in the earth. Likewise in places where hot water runs, plants are often generated, because the heat of the water draws up fresh exhalations onto the earth, while the cold nature of the water's moisture remains below, [section 9] and the air within this moisture is compacted together. And when the heat of the air has been concocted, in this too a plant is generated again, but not otherwise, unless over a long span of time. [section 10] The small plants that appear in sulfurous places come to be when winds blow sharply and produce a counter-blast and strike against each other, and the air within them is stirred up and the place is heated and fire comes to be from this, and after this what is deep down — orpiment — is generated, which descends from the sediment of the air, and draws fire together with decomposition (for this is what orpiment is); for then plants come to be from this.
17| [section 11] These do not put forth many leaves, as we showed earlier, because good mixture is far removed from them. But whatever plant bears something nourishing grows in places that are warm, light, and high, and more so in the third and fourth climate zone; and again, whatever tree produces something close to nourishing grows in places that are high and cold. [section 12] And for this reason the species multiply in such places, on account of the drawing-up of moisture and the good mixture from the sun's heat in the winter days. Likewise, natural clay quickly brings forth rich plants; for the compacting of its moisture occurs in sweet-water places, as we said before. [section 1] Again, the plant that is generated in solid stones comes about over a long time. For the air enclosed within these forces its way up, and finding no exit because of the strength of the stones, it turns back on itself and heats itself, and it draws up the moisture left behind in the stones, and an exhalation comes out together with moisture, along with the breaking-down of the smallest parts within the stones. [section 2]
18| For it is often the case with stones that the sun helps them through its own concoction. And thus a plant is generated from them. But it does not rise up unless it is near earth or moisture. For the plant's substance needs earth, water, and air. Let the plant, then, be considered thus: if it is near the sun, it is generated quickly; but if the sun is toward its setting, it is slow. [section 3] Again, in a plant where water dominates, it does not allow air to rise, and for this reason the plant is not nourished. Likewise, when dryness prevails, the natural heat turns back to the extremities, and it stops up the plant's passages through which the pores run; and for this reason the plant is not nourished. [section 1] In a general account, every plant needs four things: a determinate seed, a fitting place, water in due measure, and air of the right kind. When, then, all these are brought together, a plant is generated and grows; but when these withdraw, the plant too weakens with their withdrawal. [section 2] Again, the plant that grows on high mountains, if it forms a species, will be more readily available and better suited for medicinal use; but fruit that is harder to digest does not, for the most part, nourish. Places far removed from the sun are not productive of many kinds of plants,
19| [section 3] Likewise, if the sun in its motion adds length to the day and overpowers the moisture, the plant does not have the power to put forth leaves and fruits. But what should we think about the plants generated in watery places? In these, when the water is still, something like mud comes to be, and there is no power in the air to give support to the parts of the water. [section 4] For this air itself is held within the inner parts of the earth, and it prevents the thickness of the water from rising up. [section 5] If, then, wind should sweep into that place and the earth is drawn tight, and the enclosed air presses itself together, and the wind compacts the moisture, plants will come forth from this moisture that do not differ much from one another in species and shape, on account of the persistence and thickness of the water and the heat of the sun from above. [section 6] Again, concerning the plants that are in moist places, whose surface appears greenish to the eye of the earth, I say that in that place the porosity is slight. [section 7]
20| When, then, the sun falling upon it stirs the moisture in that place, and heats the place by the motion that results and by the heat enclosed within the inner parts of the earth — which indeed does not happen in places where the plant has nothing from which it might grow — and the moisture is diffused through its own extension, a vapor comes to be above the earth like a greenish web, and from this a plant is generated that has no leaves, belonging to the kind of plant that appears on the surface of water. [section 8] It is larger than that one, because it is close to the earth, even though it cannot rise up and extend itself further. Often, too, another plant is generated within plants that is not of the same species or the same likeness, without a root. [section 9] This is set in motion as follows: whenever a plant of many thorns stirs itself in rich water, its parts open up, and the sun draws up the decompositions within it, and produces concoction in it, and by its own nature supplies help to the decomposed place with well-tempered heat, and from this the plant grows, so that threads seem to extend throughout it entirely. [section 10]
21| And this is peculiar to plants that have many thorns. It is then that the plant called mercury (linozostis) is produced, and those like it. All plants — whatever grows above the earth and in the earth — proceed from some one of these five: seed, moisture from water, a suitable place, air, and planting. And these five are, one might say, the roots of plants. [section 1] The productiveness of trees follows in three ways: for they bring forth their fruit either before the leaves, or together with the leaves, or after the leaves. There is, moreover, a plant that has neither root nor leaves; and there is also one that bears a stem without fruit and without leaves, as the plant called goldylocks or chrysitis. [section 2] But the plants that bring forth their fruit before their leaves have great richness of moisture. For when the heat naturally present in the plant is extended, its concoction is also quickened; it grows strong and seethes in the branches of the plant, and it prevents the sap from rising up out of it; and from this fruits and leaves come forth. [section 3]
22| In the plants that put forth their leaves more quickly, what must we understand? The conditions of the moisture are many. Whenever, then, the sun's heat begins to scatter the parts of the water, the sun draws the parts of the moisture upward, and ripening is delayed, because the concoction of the fruit occurs only when there is a compacting; and the leaves come before the fruits because of the drawing-on of the abundant moisture. [section 4] Often, too, richness happens to them, whenever the moisture in the plant undergoes concoction and a dense vapor rises up from it, and the air together with the sun draws it up; for then, out of that moisture, richness and fruit and leaves all come forth in a single emission. The wise men of old maintained that all leaves are fruits. [section 5] It must be understood, then, that whenever the moisture is so great that it is neither ripened nor compacted, because of the loosening that comes from the air and the eagerness of the sun's drawing from above, then this moisture, in which no concoction has been worked, is changed into leaves; and these have no other purpose than the drawing-off of the moisture, and to serve also as coverings for the fruits against the violence of the sun.
23| [section 6] It is not necessary, then, that the leaves be like the fruits in the same way; for the sap that rises up, once altered, is what the leaves are, as we have said. The judgment is the same, too, in the case of olive trees, which are often deprived of their own fruit. [section 7] For whenever nature brings about concoction, what has not been ripened by the heat rises up first, on account of its fineness. This moisture, then, is the leaves, and the concoction is the flower. And when the concoction is completed in the second year, fruits are generated, and the matter comes out to its completion according to the place assigned to it within them. [section 8] Thorns likewise belong to the genus of plants, though not to the same nature. I say, then, that there is looseness of texture in the plant, and at the origin of its nature there is concoction, and cold moisture rises up, and with it a slight separation, passing through that looseness of texture. The sun, then, makes this compact, and from this the thorns arise. [section 9] For this reason their shape, too, is pyramid-like; for their base begins thick and proceeds to a slender point. This happens because the air, extending itself little by little through the plant, increases its parts along with the intensification of its matter. In this same way every tree or plant whose top is pyramid-shaped comes to be.
24| [section 1] The greening color must be a thing most common among trees. For we see that, just as whiteness is common within, so greenness is common without. And this is because they make use of matter that is nearer to completion, that is, more thoroughly concocted. [section 2] It is necessary, then, that there be greenness in all plants, because the materials draw and loosen the wood of the tree, and the heat works a slight concoction, and some moisture remains there, which shows on the outside; and this is the greenness that is in plants, unless the concoction becomes greater. It ought to be intermediate in power between the leaves and the wood. [section 3] Greenness is not destroyed, so long as there is moisture in it that belongs to the genus of earth. From both of these, then, the green color arises. A sign of this is that the bark of a tree, when the tree dries out, turns black, while within it remains white. In trees, then, between these two colors, a green color arises on their surface. [section 4] Of the shape of plants there are three kinds: some grow upward, some downward, some in between. Those that extend upward have this cause: their nature shows itself in the pith, and it draws the heat, and compresses within itself the air that is in its loose parts.
25| [section 5] They take a pyramid shape just as fire takes a pyramid shape in its own fuel and rises lightly upward. But those that extend downward — their pores become compacted. For when concoction occurs, then the matter of the moisture, in which the pith is, becomes dense. From this, what is fine passes upward, but the moisture turns back toward those lower parts, for its own weight moves it there. Those plants that are intermediate between the two are disposed as follows. [section 6] The moisture is made fine, because the nature of its good temperament borders closely on concoction, and the pores are intermediate, and the matter extends both upward and downward. [section 7] The first concoction occurs beneath the plant, and the second in the pith, which comes forth from the earth but is also present in the middle of the plant; and after these the division occurs, which follows from the second concoction, not from the first. [section 8] The third concoction is in the animal; for this concoction occurs only through the division of the nature of the limbs and the separation of the natural parts from one another. Plants, however, are neighbors to themselves, and for this reason they multiply in many places. For the most part, the matter of plants extends downward,
26| [section 9] The shapes of plants, then, lie in the nature and the quantity of their seeds, while the flowers of plants and their fruits lie in their moistures and in their matter. The first motion, then, and concoction are established universally in all animals, and no animals depart from it. [section 10] In plants there is first the concoction, then the ripening, according to their nourishment. Each tree, then, keeps growing upward until it is filled out. The cause of this is that, in the case of each animal, its length is close to its own breadth, but in the plant it is far greater, because its root — that is, the fire and the water in it — hasten upward, so that the plant may be brought into being. [section 11] The difference among plants in their branches arises from the excess of their looseness of texture. For when the saps are compressed together, nature grows warm and hastens toward concoction, and from this the branches are shaped and the leaves grow, as we said before. [section 1] The falling of the leaves of trees occurs because of the onset of a sharp looseness of texture. For when the moisture, together with the matter, is concocted, it takes on a pyramid shape, and after this the leaves grow thin. And when the matter appears filled out by the concoction, then the upper ends of the pores are completely stopped up. And for this reason, since the leaves no longer have matter, they dry up and fall.
27| [section 2] But if the opposite of what we have said occurs, the plant does not fall into the loss of its own leaves. And again, when cold sets the plant in motion, the heat enclosed within it warms it, and the manifestation of the cold occurs outwardly at its extremities, and from this the leaves are made grey-green, and they do not fall, as is the case also with olives and myrtles and the rest. [section 3] Now whenever trees and plants have a strong power of drawing, fruit-bearing occurs together with this; and this comes about because nature makes use of concoction in frequent succession, and in each concoction it brings forth much fruit. And for this reason some plants also bear fruit many times within the year. [section 4] But the plant which is, as it were, of a watery nature bears fruit only with difficulty, on account of the dominance of its moisture and the widening of its own pores and the outflow from its own roots. But when the heat grows strong, its concoction becomes swift, and the moisture is thinned and does not congeal; and even so it again happens that fruit-bearing does not occur. [section 5] And this is found in all the slender herbs, and indeed also in certain vegetables. Now a dun-grey color occurs in places that are extremely hot, and in these there is little fruit from the moisture, because the pores are narrow. Whenever, then, nature wishes to bring about concoction, not having moisture sufficient for the matter, then the pores become narrower.
28| [section 6] Concoction, then, turns back on itself, and the heat makes it continuous, and at that point what appears is the mean between white and black in color. And when this comes about in this way, then the wood comes to be black, and everything approaching the dun-grey; and this one can see from ebony and elm. [section 7] Ebony sinks in water, because its parts are compacted together and its pores are narrow, and air does not enter into them. But wood from the white timbers is submerged for a different reason, namely the narrowness of the pores together with the excess of moisture that blocks the pores, so that air cannot get out of them. [section 8] The flower, when concoction begins, is made of fine matter only; and for this reason it precedes the plant, as we have shown. From this, then, we also show the cause for which plants put forth leaves first, and then fruits. That which becomes a color in the plant having narrow pores will be a sapphire color, and because its parts are compressed together, it inclines toward whiteness. [section 9] But when it arrives at a good mixture, it is grey-green. And the reason why some plants have no flowers at all is that, for the most part, this happens on account of the difference among the parts within them and the fineness, roughness, and thickness present in them.
29| [section 10] Palm trees, fig trees, and things like them have no flowers. And the plant that has thick bark spreads out in accordance with the extension of its moisture and the pressing together of its heat; and this is the case in the pine and the palm. [section 11] The plant that discharges milky sap has this in its middle part. For the heat below is stronger, and richness remains there. Whenever, then, the heat begins to concoct, the richness turns into its own proper moisture, and it congeals this with a slight congealing. [section 12] And as the place is heated, the moisture becomes oily, like milk, and a vapor rises from the moisture that draws that milk up to the extremities, and the moisture holds fast the heat that appears, and thus the milk congeals; for it is the nature of heat to cause congealing. [section 13] Now milk of a very thick congealing comes about precisely when cold shows itself in the tree; for being congealed after this, it comes out from its own place. And from this is gum. Warm gum comes forth in the act of dripping; whenever, then, it touches the air, it congeals and flows down in a temperate place, and it is like water,
30| [section 14] while another kind is poured out and congeals like stones or shellfish. But when it flows in a trickle, remaining in its own proper form, it becomes what is called amber-resin. And that which is altered becomes, to all appearance, like stone, extremely cold. Heat makes it become such as this; but when it is cold and flows down, it turns to stone. [section 15] Again, some trees are altered in winter, and become at one time green, at another grey-green, and neither their leaves nor their fruits perish, because the plants in which this happens have a thick heat above and a fine moisture in their roots; hence, in the course of the year, the moisture retains that color on account of the coldness of the air. [section 16] And when the heat comes up against the cold, the heat pushes the moisture outward, together with the color it has dyed, which follows along on the surface of the tree. But when the cold and the dryness turn again into activity, and the moisture retains the heat, then the grey-green color appears. [section 1]
31| Fruit becomes bitter when the heat and the moisture are not full in the concoction. For the cold and the dryness hinder the completion, and thus the fruit turns to bitterness. A sign of this is that the bitter thing, thrown into fire, becomes sweet. Trees that are born in sour water produce sweet fruit, because the sourness draws along with the heat of the sun, which is of its own proper quality. [section 2] And this is cold and dryness; and from this some small quantities of moisture remain within, sweet ones. The cavity of the tree is also heated, when the sun stays upon it, and thus the flavor of the fruit becomes a little astringent. And the more it is concocted, the more the sourness is dissolved little by little, until it is used up and the sweetness appears. [section 3] The fruit, then, will be sweet, but its leaves and twigs dry. But when ripeness is completed, the fruit becomes more bitter still. This is on account of the excessive heat together with scant moisture. For the moisture is used up, and the fruit makes the heat rise, and then the fruit is bitter. And also
32| [section 4] the stones become pyramid-shaped on account of the drawing-in of the heat and the excessive cold and moisture lying within, which are of the class of sour water. For the moisture remains in the middle and is compacted, and thins out the extremities. [section 5] Trees that are in temperate soil hasten their ripening before the winter days, because when the heat draws near a good mixture, and the moisture also becomes evident and the air clear, and the fruit does not need much moisture or concoction, then its ripening hastens, and it comes forth before the winter days. [section 6] In all trees, then, when they are first planted, the bitter or the harsh predominates, since the moisture, when it is at their extremities, concocts the regions that are in the middle of the trees, from which the matter of the fruits also comes, and dryness comes forward and follows upon the moisture, and thus the first concoction becomes sharp or bitter or harsh. [section 7] The cause is that concoction occurs by means of heat together with moisture. But when moisture and dryness prevail over the heat, the fruit that comes from it is at the beginning not well concocted, because the generation of the fruit at the beginning is without sweetness. But the fruits of the myrobalan trees, when they first appear, are sweet; though commonly they are harsh and, in their mixture, bitter.
33| [section 8] The cause is that the tree of these plants is loose-textured in its branches. In the season of ripening, when the pores are wide, heat follows upon moisture, and the fruits ripen, and at the start they are sweet. Then again, correspondingly, because of this looseness the tree draws in further passages, and coldness and dryness come to prevail over the hot and the moist, and from this the fruits change into astringency. [section 9] Again the sun prevails, together with heat, through the drawing off of the excess dryness in that seed which is on the surface of the trees, and coldness overcomes dryness, and the fruits are of strong astringency. From this, in turn, natural heat rises upward, and the heat of the sun from outside assists it, and heat and dryness prevail, and the fruits become bitter.