Dicimus itaque ignem et aerem et aquam et terram fieri ex invicem, et unumquodque horum in unoquoque existere in potentia, sicut et aliorum quibus unum aliquid et idem subiicitur, in quod etiam resolvuntur ultimum. Fire, air, water, earth, we assert, originate from one another, and each of them exists potentially in each, as all things do that can be resolved into a common and ultimate substrate. Primum quidem igitur dubitabit utique quis circa vocatum aerem, quam oportet accipere ipsius naturam in mundo ambiente terram, et quomodo se habet ordine ad alia dicta elementa corporum. The first difficulty is raised by what is called the air. What are we to take its nature to be in the world surrounding the earth? And what is its position relatively to the other physical elements. Moles quidem enim utique terrae quanta quidem utique sit ad ambientes magnitudines, non immanifestum. Iam enim visum est per astrologica theoremata a nobis quod multo etiam quibusdam astris minor est. (For there is no question as to the relation of the bulk of the earth to the size of the bodies which exist around it, since astronomical demonstrations have by this time proved to us that it is actually far smaller than some individual stars. Aquae autem naturam constantem et separatam neque videmus, neque contingit separatam esse ab eo quod circa terram locato corpore; puta a manifestis, mari et fluminibus, et utique si quid in profundo immanifestum est nobis. As for the water, it is not observed to exist collectively and separately, nor can it do so apart from that volume of it which has its seat about the earth: the sea, that is, and rivers, which we can see, and any subterranean water that may be hidden from our observation.) Intermedium autem terrae et ultimorum astrorum, utrum unum aliquod putandum secundum naturam esse corpus, aut plura? Et si plura, quot, et usquequo determinata sunt locis? The question is really about that which lies between the earth and the nearest stars. Are we to consider it to be one kind of body or more than one? And if more than one, how many are there and what are the bounds of their regions? Nobis quidem igitur dictum prius est de primo elemento, quale secundum virtutem est; et quia totus qui circa superiores lationes mundus, illo corpore plenus est. Et hanc opinionem non solum nos existimus habentes, videtur autem antiqua quaedam existimatio ipsa et priorum hominum. Dictus enim aether antiquam accepit appellationem; quam Anaxagoras quidem igni idem mihi putasse videtur significare, putans superiora plena igne esse; et ille eam quae ibi potentiam aethera vocari putavit, hoc quidem recte putans. Quod enim corpus semper currens, simul et divinum aliquid secundum naturam visi sunt existimare, et determinaverunt nominari aethera quod tale, tanquam nulli eorum quae apud nos existens idem. Non enim dicemus semel neque bis neque raro easdem opiniones reiterare factas in hominibus, sed infinities. We have already described and characterized the first element, and explained that the whole world of the upper motions is full of that body. This is an opinion we are not alone in holding: it appears to be an old assumption and one which men have held in the past, for the word ether has long been used to denote that element. Anaxagoras, it is true, seems to me to think that the word means the same as fire. For he thought that the upper regions were full of fire, and that men referred to those regions when they spoke of ether. In the latter point he was right, for men seem to have assumed that a body that was eternally in motion was also divine in nature; and, as such a body was different from any of the terrestrial elements, they determined to call it 'ether'. For the same opinions appear in cycles among men not once nor twice, but infinitely often. Quicumque autem ignem purum esse aiunt quod ambiens, et non solum lata corpora; quod autem intermedium terrae est et astrorum, aerem; considerantes utique nunc ostensa per mathematica sufficienter, forte utique desisterent ab hac puerili opinione. Valde enim simplex putare unumquodque latorum esse parvum magnitudinibus, quia videtur aspicientibus hinc nobis sic. Dictum est quidem igitur et prius, in his quae circa superiorem locum theorematibus: dicimus autem eandem rationem et nunc. Si enim et distantiae plenae igne, et corpora constant ex igne, olim annihilatum utique esset unumquodque aliorum elementorum. Now there are some who maintain that not only the bodies in motion but that which contains them is pure fire, and the interval between the earth and the stars air: but if they had considered what is now satisfactorily established by mathematics, they might have given up this puerile opinion. For it is altogether childish to suppose that the moving bodies are all of them of a small size, because they so to us, looking at them from the earth. This a matter which we have already discussed in our treatment of the upper region, but we may return to the point now. If the intervals were full of fire and the bodies consisted of fire every one of the other elements would long ago have vanished. At vero neque aere solo plena: multum enim utique excederet aequalitatem communis analogiae ad coelementaria corpora. However, they cannot simply be said to be full of air either; Et etiam si duobus elementis plenus qui intermedius terrae et caeli locus est. Nulla enim, ut est dicere, pars terrae est moles, in qua contenta est et omnis aquae multitudo, ad ambientem magnitudinem. Videmus autem non in tanta magnitudine factum excessum molis, cum ex aqua disgregata aer fiat, aut ignis ex aere: necesse autem eandem rationem habere, quantam habet tantilla et parva aqua ad factum ex ipsa aerem, et totum ad totam aquam. for even if there were two elements to fill the space between the earth and the heavens, the air would far exceed the quantity required to maintain its proper proportion to the other elements. For the bulk of the earth (which includes the whole volume of water) is infinitesimal in comparison with the whole world that surrounds it. Now we find that the excess in volume is not proportionately great where water dissolves into air or air into fire. Whereas the proportion between any given small quantity of water and the air that is generated from it ought to hold good between the total amount of air and the total amount of water. Differt autem nihil neque si quis dicat quidem non fieri haec ex invicem, aequalia tamen virtute esse. Secundum enim hunc modum necesse est aequalitatem virtutis existere magnitudinibus ipsorum, quemadmodum utique si facta ex invicem existerent. Nor does it make any difference if any one denies that the elements originate from one another, but asserts that they are equal in power. For on this view it is certain amounts of each that are equal in power, just as would be the case if they actually originated from one another. Quod quidem igitur neque aer neque ignis tantum replet intermedium locum, manifestum est. So it is clear that neither air nor fire alone fills the intermediate space. 15. Ostenso quae sunt principia activa et quae sunt principia materialia passionum de quibus intendit tractare, incipit nunc determinare de eis. Et dividitur in partes duas: 15. Having identified which are the active principles and which the material principles of the passions which he intends to treat, he now begins to determine concerning them. And this is divided into two parts: in prima determinat de particularibus transmutationibus elementorum quibus secundum se transmutantur; in the first he determines concerning the particular transmutations of the elements, whereby they are transmuted according to themselves; in secunda determinat de transmutationibus eorum secundum quod veniunt in compositionem mixti, in quarto libro, ibi: quoniam autem quatuor et cetera. second, he determines about their transmutations accordingly as they enter into composition to form a mixture, in Book IV. Prima autem pars dividitur in duas: The first part is divided into two parts: in prima enim determinat de transmutationibus seu passionibus elementorum quae in alto accidunt; in the first he determines concerning the transmutations or passions of the elements which occur on high; in secunda de his quae accidunt in infimo, et hoc in secundo libro, ibi: de mari autem et cetera. in the second, about those which occur below, and this in Book II. Prima autem pars dividitur in tres: The first part is divided into three parts: in prima dicit de quo est intentio; in the first he declares what his intention is; in secunda praemittit quaedam quae sunt necessaria ad subsequentium determinationem, ibi: dicimus itaque ignem et aerem etc., in the second he states certain preliminaries necessary for determining what is to follow, at fire, air, water, earth, we assert (339a36); in tertia incipit determinare de principali proposito, ibi: his autem determinatis et cetera in the third he begins to determine concerning his main proposition, at having determined these principles (341b1). Dicit ergo primo quod dicendum est de phantasia lactis, idest de apparitione lactei circuli, et de cometis, et de aliis omnibus huiusmodi quae sunt his syngenea, idest congenerabilia; ita tamen quod resumamus positiones a nobis positas in prioribus libris, et determinationes in eis prius determinatas, ut eis utamur ad propositum manifestandum, cum opus fuerit. He says therefore first that we must speak of the image of the milk (339a33), i.e., of the appearance of the milky circle, and of comets and of all other like things which are syngeneous, i.e., generable along with them; but in doing so we shall [first] recall the positions laid down by us in the earlier books and the determinations already determined therein, so that we may, when necessary, use them to manifest the proposition. 16. Deinde cum dicit: dicimus itaque ignem et aerem etc., praemittit quaedam quae sunt necessaria ad subsequentia. Et circa hoc duo facit: 16. Then when he says, fire, air, water, earth, we assert (339a36), he sets forth certain things needed for what is to follow. About this he does two things: primo praemittit aliquid quod pertinet ad transmutationem elementorum adinvicem; first, he premises something pertaining to the mutual transmutation of the elements; secundo dicit de ordinatione eorum in mundo, et specialiter de aere, ibi: primum quidem igitur dubitabit et cetera. second, he speaks of the arrangement of the elements in the world, with special emphasis on air, at the first difficulty is raised (339b2). Dicit ergo primo quod ignis et aer et aqua et terra fiunt ex invicem, quamvis Empedocles contrarium senserit: et hoc resumit ut probatum in II De generat. Et huius rationem assignat, quia unumquodque elementorum est in alio in potentia; et quae sic se habent, adinvicem generari possunt. Ulterius huius rationem assignat, quia communicant in una materia prima, quae eis subiicitur, et in quam sicut in ultimum resolvuntur: omnia enim quorum materia est una communis, sic se habent quod unum eorum est potentia in alio; sicut cultellus est potentia in clavi, et clavis in cultello, quia utriusque materia communis est ferrum. He says therefore first that fire and air and water and earth are produced from one another (even though Empedocles thought the contrary). And he restates this as proved in On Generation II. The reason for this which he assigns is that each element exists potentially in another, and that things so related can be generated one from the other. He assigns a further reason, which is that they all have the same common first matter which underlies each of them and into which, as into an ultimate, they are all resolved: for all things whose matter is one and common to all are so related that any one is potentially in any other—as, for example, a knife is potentially in a nail, and a nail potentially in a knife, because they have a common matter, iron. 17. Deinde cum dicit: primum quidem igitur dubitabit etc., inquirit de ordine elementorum, et praecipue aeris. Et circa hoc tria facit. 17. Then when he says, the first difficulty is raised (339b2) he inquires into the order of the elements and into the case of air in particular. About this he does three things. Primo movet quaestionem: et dicit quod primo dubitatur circa corpus quod vocatur aer, quam naturam habeat in mundo qui ambit terram, utrum scilicet totum sit aer; et si non, quomodo ordinetur ad alia elementa. First he raises the question and says that our first problem is about the body called "air," as to what nature it has in the world surrounding the earth: i.e., is the whole air, and, if not, how it is related to the other elements? Secundo ibi: moles quidem enim etc., proponit quaedam circa ordinem elementorum manifesta. second at for there is no question as to the relation of the bulk (339b6), he proposes certain evident facts about the order of the elements. Quorum primum est de terra: scilicet quod non est immanifestum quanta sit moles terrae, per comparationem ad magnitudines ambientes, scilicet caelestium corporum et aliorum elementorum. Iam enim apparuit per considerationes astrologicas, quod terra est multo minor quibusdam astris, et quod in comparatione ad ultimam sphaeram obtinet vicem puncti. The first fact concerns the earth, and it is that we are not entirely ignorant of the size of the earth in comparison to the surrounding magnitudes, namely, those of the heavenly bodies and of the other elements. For it is already plain from the considerations of astronomers that the earth is much smaller than certain stars, and that it is but the size of a point in comparison to the outermost sphere. Secundum proponit de aqua, ibi: aquae autem naturam et cetera. Et dicit quod non videmus aquam per se constantem, et separatam a corpore locato circa terram, scilicet a mari et fluminibus, quae sunt manifesta nobis, et a congregationibus aquarum, si quae sunt in profundo terrae immanifestae nobis, ut quidam posuerunt. Nec etiam contingit aquam sic congregatam esse: eo quod humidum aqueum non terminatur nisi termino alieno. The second fact he proposes is about water, at as for the water (339b9). And he says that we do not observe water to exist by itself and isolated from the body located about the earth, namely, from the sea and rivers, which we see, and from the bodies of water which some have asserted to exist hidden from us in the bowels of the earth. For it does not occur to water to be gathered together in this way—since the moistness which is water is contained by some alien terminus. 18. Iterum ibi: intermedium autem terrae etc., hic prosequitur quaestionem suam iam motam, qua quaerit quid est inter praedicta medium. Et circa hoc duo facit. 18. He further at the question is really about that which lies between the earth (339b13), pursues the question he raised earlier, namely, as to what is the middle between the aforesaid [i.e., the earth and the farthest stars]. About this he does two things: Primo enim ostendit quod non totum spatium quod est a supremis stellis usque ad terram, est plenum uno aliquo corpore, scilicet igne vel aere, aut utroque; sed supra hoc est aliquod corpus praeter ista. first, he shows that it is not the case that the entire space from the highest stars to the earth is filled with some one body such as fire or air or both, but that above there is an additional body besides these; Secundo ostendit quomodo ad illud supremum corpus ordinentur alia corpora secundum positionem, ibi: reliquum est autem et cetera. second, he shows how the other bodies are related to that highest body with respect to position, at it remains to explain (340a19). Circa primum sic procedit. Regarding the first he proceeds thus. Primo dicit quod dubium est utrum inter terram et inter astra ultima, quae dicuntur non errantia sed fixa, sit putandum esse unum corpus, secundum proprietatem naturae, vel plura: et si plura, quot sunt, et ubi terminentur secundum locum. First he says that there is a problem whether between earth and the farthest stars, which are called "non-wandering" and "fixed," we should posit, according to what is proper to nature, one body or more than one; and if more than one, how many, and where are the boundaries of their regions?