Si quidem enim latitudinem habeant et longitudinem hypeccaumata, multoties videntur accensa sicut flamma, velut in area ardentis stipulae. Si autem secundum longitudinem solum, vocati dali et aeges et sidera. Si quidem plus hypeccauma fuerit secundum longitudinem quam latitudinem, quando quidem quasi exscintillat simul combustum (hoc autem fit propter igniri secundum modica quidem, ad principium autera), aeges vocatur; quando autem sine hac passione, dalus; quando vero longitudines exhalationis per modica et multipliciter dispersae fuerint, et similiter secundum latitudinem et profunditatem, sidera putata volare fiunt. Aliquando quidem igitur a motu exhalatio exusta generat ipsa: aliquando autem, sub frigore consistente aere, extruditur et segregatur calidum; propter quod et latio ipsorum assimilatur magis proiectioni, sed non exustioni. If this is broad and long, we often see a flame burning as in a field of stubble: if it burns lengthwise only, we see what are called 'torches' and 'goats' and shooting-stars. Now when the inflammable material is longer than it is broad sometimes it seems to throw off sparks as it burns. (This happens because matter catches fire at the sides in small portions but continuously with the main body.) Then it is called a 'goat'. When this does not happen it is a 'torch'. But if the whole length of the exhalation is scattered in small parts and in many directions and in breadth and depth alike, we get what are called shooting-stars. The cause of these shooting-stars is sometimes the motion which ignites the exhalation. At other times the air is condensed by cold and squeezes out and ejects the hot element; making their motion look more like that of a thing thrown than like a running fire. 38. Positis his quae ad manifestationem sequentium philosophus induxerat, 38. Having laid down those things introduced to explain what is to follow, the Philosopher begins: incipit primo determinare de his quae in alto ex materia sicca generantur; first, to determine concerning things generated on high out of dry matter; secundo de his quae generantur ex materia humida in alto, ibi: de loco autem positione et cetera. second, things generated on high from moist matter, at let us go on to treat of the region (346b16). Prima dividitur in tres: The first is divided into three parts: primo determinat de stellis cadentibus, et his quae similem habent causam; in the first he determines about falling stars and things having a like cause; secundo determinat de cometis, ibi: de cometis autem etc.; in the second about comets at let us go on to explain the nature of comets (342b25); tertio de lacteo circulo, qui dicitur Galaxia, ibi: qualiter autem et propter quam causam et cetera. in the third about the milky circle called the "galaxy" at let us now explain the origin, cause, and nature (345a11). Circa primum duo facit: About the first he does two things: primo enim determinat de stellis cadentibus et aliis huiusmodi; first, he determines about falling stars and other similar things; secundo determinat de quibusdam aliis apparitionibus quae in aere videntur, ibi: apparent autem aliquando nocte et cetera. second, about certain other apparitions seen in the air, at sometimes on a fine night (342a34). Circa primum duo facit. About the first he does two things: Primo dicit de quo est intentio. Et dicit quod post determinationem praedictorum, dicendum est propter quam causam apparent in caelo flammae accensae, et sidera discurrentia, et vocati a quibusdam dali, idest titiones, et aeges, idest caprae. Ideo autem dicendum est simul de omnibus istis, quia omnia huiusmodi sunt idem secundum speciem, et secundum eandem causam fiunt; sed differunt per magis et minus, ut infra patebit. first, he states his intention and says that, having determined the foregoing, we must explain the cause of the appearance in the heaven of burning flames and of shooting stars and of so-called dali (341b1), i.e., torches, and aeges, i.e., goats. They will be discussed at one and the same time, because they are all alike in kind and produced by the same cause, and differ only in degree, as will be clear below. 39. Secundo ibi: principium autem et horum etc., determinat propositum. Et circa hoc duo facit. 39. second at the explanation of these (341b5), he determines his proposition, about which he does two things. Primo praemittit causas generationis praedictorum. Et dicit quod principium praedictarum passionum et multarum aliarum, tam activum quam materiale, est quod dicetur. Cum enim terra calefacta fuerit per motum solis, oportet aliquam exhalationem resolvi a terra. Quae non est uniusmodi, ut quidam putant, sed est duplex: quaedam enim est magis vaporosa et humida, quaedam vero est magis spumosa et sicca: nam ab humido aqueo quod est super terram, resolvitur et elevatur vaporosa exhalatio et humida; ab ipsa autem terra, quae est siccae naturae, elevatur exhalatio fumosa sive spumosa. Harum autem exhalationum, spumosa quidem supereminet propter calidum, quod in ea dominatur et magis ipsam subtiliat: siccum enim et calidum leve est, et talis est ignis natura. Vaporosa autem exhalatio, quae est magis humida, subest spumosae propter pondus, non enim ita rarefit: calidum enim et humidum pertinent ad naturam aeris, qui subest igni calido et sicco existenti. First, he states the causes generating the aforesaid, and says that the principle, both active and passive, of the aforesaid phenomena and of many others is what he will indicate. For when the earth has been warmed by the sun's motion, a certain exhalation is necessarily released from the earth. This is not of one sort, as some think, but is twofold: one is more vaporous and moist, the other more foam-like and dry—for from the aqueous moisture upon the earth's surface there is released and lifted on high a vaporous exhalation which is moist; from the earth itself, which is by nature dry, there is raised a fume-like or foam-like exhalation. Of these, the foam-like exhalation rises above the other on account of warmth which dominates in it and renders it more subtle: for the dry and warm is light—and fire is of this nature. But the vaporous exhalation, which is more moist, finds its place under the foam-like, being heavier, for it is not so fine: hot and moist pertain to the nature of the air, which is below fire, which is hot and dry. Et huic attestatur ordo elementorum quae sunt circa terram. Nam sub circulari motu caeli primo est locatum id quod est calidum et siccum, quod communiter dicitur ignis, licet non sit nomen proprium, ut supra dictum est: quia enim id quod est commune omni fumosae exhalationi, est innominatum, et quod tale est maxime natum est exuri, propter hoc sic necessarium fuit uti nominibus, ut talis fumosa exhalatio ignis diceretur. Sub fumosa autem exhalatione est aer. Sic ergo posita est causa et effectiva praedictarum passionum, quae est latio solis, et causa materialis, quae est fumosa exhalatio. The very order of the elements surrounding the earth attests to this. For under the circular motion of the heaven there is first located what is hot and dry and which is commonly called "fire," though that is not its proper name, as has been said above: for, since the item common to every smoky exhalation has no name, and such is especially apt to burn, consequently, it was necessary to use words in keeping, and so such a fume-like evaporation comes to be called "fire." Under this fume-like exhalation is air. Thus we have posited both the effective cause of the aforesaid passions, which is the sun's movement, and the material cause, namely, the fume-like exhalation. 40. Secundo ibi: oportet autem intelligere etc., determinat de generatione praedictarum passionum. Et circa hoc duo facit: 40. second at we must think (341b18), he determines concerning the generation of the aforesaid passions. About this he does two things: primo assignat rationem generationis harum passionum; first, he assigns the cause of their generation; secundo assignat rationem quorundam accidentium circa ipsas, ibi: propter positionem et cetera. second, the reason why certain things accompany them, at the motion is upwards or downwards or sideways according to the way in which the evaporation lies (342a21). Circa primum tria facit: About the first he does three things: primo assignat causam praedictarum passionum in communi; first, he gives the cause of the aforesaid passions in common; secundo assignat differentiam earum adinvicem, ibi: quacumque igitur se habeat maxime etc.; second, their mutual differences, at so whenever the circular motion stirs this stuff up (341b22); tertio movet dubitationem circa determinata, ibi: dubitabit utique quis et cetera. third, he raises a question concerning what he has determined at for the question might be raised (342a3). Dicit ergo primo quod, secundum praedicta, oportet intelligere hoc quod nunc diximus ignem, scilicet fumosam exhalationem, esse ut quoddam hyppeccauma, idest quandam materiam incendii; et quod ordinatur in rotunditate quae est circa terram ultimo (incipiendo scilicet a terra); ita quod propter propinquitatem ad motum caelestem, saepe exuratur, sortiens augmentum caloris, modico motu, idest cum parum movetur ex motu superioris corporis; sicut accidit de fumo, dum incenditur et fit flamma: nihil enim est aliud flamma quam ardor spiritus, idest fumi, sicci. Ipsa ergo flammatio praedicti hypeccaumatis, communiter loquendo, est generatio praedictarum passionum, ex appropinquatione materiae praeparatae causae efficienti. He says therefore first that, in the light of the foregoing, we must understand what we have just now called "fire" to be as a certain fuel (341b18), i.e., a combustible material, and that it is situated in the sphericity which is about the earth in the last place (beginning, that is, from the earth), Hence, on account of its proximity to the heavenly motion it often bursts into flame, being heated when only slightly moved, i.e., when slightly stirred by the motion of the body above it, as happens in the case of smoke, when it is ignited and becomes flame: for a flame is nothing but the burning of a dry spirit, i.e., smoke. Therefore the ignition of the above-mentioned fuel, commonly speaking, is responsible for the generation of the aforesaid passions, when matter which is prepared is placed in the proximity of the efficient cause. 41. Deinde cum dicit: quacumque igitur se habeat maxime etc., assignat differentiam praedictarum passionum. Et circa hoc duo facit. 41. Then when he says, so whenever the circular motion stirs this stuff up (341b22), he explains the differences among the aforesaid passions. About this he does two things. Primo ostendit unde sit accipienda differentia. Et dicit quod ex qua parte se habet praedicta materia (quocumque modo se habeat talis consistentia, idest praedicta materia incendii) optime disposita ad hoc quod igniatur, tali modo exuritur, quando fuerit mota per calefactionem a circulari motu caeli: et differt passio exignita secundum positionem praedictae materiae et multitudinem. First he shows what is the basis for the difference. And he says that from whatever source the aforesaid matter is had (regardless of how this consistency is obtained, namely, the aforesaid matter for burning), and when it is most perfectly disposed to be ignited, then it is so ignited in such a way by heating from the circular motion of the heaven: and the ignited passion varies according to the position and amount of the aforesaid matter. 42. Secundo ibi: si quidem enim etc., assignat differentiam praedictarum passionum. Et dicit quod si praedicta materia habeat magnam latitudinem et longitudinem, videtur esse quaedam flamma accensa in caelo, sicut cum stipula ardet in area. Si vero non habeat multum in latitudine, sed solum in longitudine, generantur et apparent illic dali, idest titiones, et aeges, idest caprae, et sidera discurrentia. 42. second at if this (341b25), he determines the differences among the aforesaid passions. And he says that if the aforesaid matter has great width and length, there appears to be a certain flame enkindled in the heaven, similar to stubble burning in a field [area]. But if it does not have great width, but only length, then dali, i.e., torches, and aeges, i.e., goats, and shooting stars are generated and appear there. Quia si praedicta materia fuerit plus secundum longitudinem quam latitudinem, et quando simul dum comburitur, ignis scintillat, idest videtur salire et discurrere quasi aeges, idest sicut caprae (quod quidem fit propter hoc quod incipit igniri non tota materia simul, sed secundum aliquas parvas partes, incipiens ex aliquo principio illius materiae): quando inquam hoc fit, tunc vocatur aeges, idest capra. For if the aforesaid matter is more in length than in width, and when it burns, the fire scintillates, i.e., seems to leap and run about like aeges, i.e., goats (which happens because not all the matter begins to be ignited at once but according to certain small sections, beginning from some starting-point in the matter), when, I say, this happens, it is called aeges, i.e., a goat. Sed quando fit incensio praedictae materiae sine praedicta passione, idest sine scintillatione, eo quod materia tota accenditur simul, tunc vocatur dalus, idest titio. But when the burning of the aforesaid matter takes place without the aforesaid passion, i.e., without scintillation, because the entire material is ignited at once, then it is called a dalus, i.e., a torch. Sed quando exhalatio non fuerit continua, sed frequens et dispersa per modicas partes et multis modis, tam secundum longitudinem quam secundum latitudinem, quam etiam secundum profunditatem, tunc fiunt sidera quae putantur volare: eo quod illa materia cito consumitur, et desinit esse ibi ubi prius accensa fuerat, sicut accidit de stuppa, si modicum de ea per longitudinem disponatur et accendatur: currit enim combustio, et videtur similis esse motui alicuius corporis ignei. However, when the exhalation is not continuous, but frequent, and scattered in small areas, and in many ways, both according to length and according to width and even depth, then appear stars that seem to fly, because the material is rapidly consumed and ceased to be where it was previously burning, as happens with flax, if a small amount of it is laid down lengthwise and ignited: for the combustion seems to run along and seems similar to the movement of some fiery body. Sic igitur patet quod plurimum habet de materia flamma accensa; mediocriter (propter quod vocantur) titiones et caprae; minimum autem stellae discurrentes, et propter hoc frequentius apparent. In this way, it is therefore plain that the burning flame has most material; a medium amount what are called "torches" and "goats," and least for shooting stars, which accounts for their rather frequent occurrence. 43. Sed quia sidera volantia habent aliam causam suae generationis, ideo subiungit quod aliquando exhalatio exusta a motu solis generat ea; aliquando autem, inspissato aere propter frigus, illud quod est ibi calidum, inspissatum extruditur inferius et separatur a frigido; et propter hoc illud inspissatum ignitur, et videtur stella cadens. Propter quod et motus siderum sic cadentium non assimilatur exustioni, sed magis proiectioni. 43. But because shooting stars have an additional cause of their generation, he adds that sometimes an exhalation ignited by the sun's movement generates them, but sometimes, too, when cold causes air to thicken, that which is hot within, being thickened, is forced out downward and is separated from the cold; this causes the thickened mass to ignite and a falling star is seen. That is also why the motion of stars falling in that way is not assimilated to a burning, but rather to a projecting. Lectio 7 Lecture 7 Solvitur quaedam dubitation circa sidera discurrentia—ratio quorundam accidentium circa ipsa Solution of problems concerning shooting stars Dubitabit utique quis utrum velut quae sub lucerna posita exhalatio a superiori flamma accendat inferiorem lucernam (mirabilis enim et huius velocitas est, et similis proiectioni, sed non in alio et alio facto igne): aut proiectiones eiusdem alicuius corporis sunt discursus. For the question might be raised whether the 'shooting' of a 'star' is the same thing as when you put an exhalation below a lamp and it lights the lower lamp from the flame above. For here too the flame passes wonderfully quickly and looks like a thing thrown, and not as if one thing after another caught fire. Or is a 'star' when it 'shoots' a single body that is thrown? Videtur itaque propter ambo. Etenim sicut a lucerna fit, et quaedam propter expelli proiiciuntur, velut quae ex digitis elabentia; ut in terram et in mare videantur cadentia, et nocte et per diem videntur, serenitate existente. Deorsum autem iaciuntur, quia coagulatio ad deorsum inclinat propellens. Propter quod et fulmina deorsum cadunt: omnium enim horum generatio non exustio, sed segregatio ab expulsione est; quoniam secundum naturam calidum sursum natum est ferri omne. Apparently both cases occur: sometimes it is like the flame from the lamp and sometimes bodies are projected by being squeezed out (like fruit stones from one's fingers) and so are seen to fall into the sea and on the dry land, both by night and by day when the sky is clear. They are thrown downwards because the condensation which propels them inclines downwards. Thunderbolts fall downwards for the same reason: their origin is never combustion but ejection under pressure, since naturally all heat tends upwards.