Chapter XVIII: Introduction (13)

Text size

------------------------------------------------------------------------ [551] “This hundredth year.” _Par._ ix. 40. ------------------------------------------------------------------------

The historical events alluded to in the _Divine Comedy_ are so often of unknown date to us, that few of them help as much as might be expected. Judge Nino’s widow remarried on June 24, 1300, and as he speaks of her as having already put off her widow’s weeds,[552] this might indicate that we are in 1301, but it is not conclusive, since they would probably be discarded three months before she was actually the wife of another. On the other hand, Can Grande della Scala, who is said in a fourteenth century chronicle to have been born on March 9, 1291, is described as only nine years old.[553] Dante might possibly have been mistaken by a year in the date of his birth, but he cannot have been ignorant of the death of his friend Guido Cavalcanti. The cry of anguish from Guido’s father will be remembered by all readers of the _Inferno_, after Dante has spoken of his friend in the past tense:—

------------------------------------------------------------------------ [552] _Purg._ viii. 74.

[553] _Par._ xvii. 80, 81.
“Di subito drizzato gridò: Come,
Dicesti _egli ebbe_? Non viv’ egli ancora?
Non fiere gli occhi suoi lo dolce lome?”[554]

[554]
“Up starting suddenly he cried out: How
Saidst thou? ‘_he had_?’ Is he not still alive?
Does not the sweet light strike upon his eyes?”
_Inf._ x. 67-69.
------------------------------------------------------------------------

And as Dante hesitates a little, Cavalcante sinks back into his tomb of punishment, and does not reappear. Before Dante leaves the place, feeling compunction, he charges Farinata to tell the father that his son is still among the living, and that the sinister hesitation was due to another cause than he thought. Now it is beyond dispute that Guido died in August 1300, for he was buried in the cemetery of St. Reparata in Florence on August 29, 1300, according to official records still extant;[555] and Dante had a share in banishing him amongst other exiles to the unhealthy place where he contracted the illness of which he died. The year 1300, in which Dante held the official position which obliged him to do this, was burned into his mind, as we see in his letter, mentioned by Lionardo Bruni, in which he says that all his misfortunes sprang from the time of his priorate.

------------------------------------------------------------------------ [555] Toynbee’s _Dante Dictionary_, under “Cavalcanti.” ------------------------------------------------------------------------

How then can we believe that he here imagines himself speaking in the spring of 1301, unless we assume that Cavalcanti had really guessed the true cause of his hesitation, and that what Dante said afterwards was a kindly lie? Is this in character with his uncompromising, even ruthless straightforwardness? Unless therefore some really satisfactory way of escape can be found from this incident and the “centesim’ anno” I fear we must reluctantly abandon the theory of 1301, championed so skilfully by Angelitti and others, and must agree with the majority that Dante means us to understand the year 1300.

The early commentators seem to have taken for granted that Dante was correct in his astronomical data, without taking any particular trouble to verify them. Jacopo della Lana in commenting _Par._ xxi. 14 says that in 1300 in the month of March Saturn was in Leo, and was in the 8th degree of that sign; and in order that we should know what was the disposition of the whole sky at that time he further informs us that Jupiter was in Aries in the 24th degree, and Mars in Pisces in the 11th degree, that the sun was near the beginning of Aries, and Venus in Pisces (these two are evidently taken simply from Dante). Mercury was in Virgo (with the sun in Aries! in this case Mercury would have been visible nearly the whole night), and the moon in . Here there is said to be a blank in all the MSS. The moon was too much for Della Lana, whether the difficulty was in finding her position or in reconciling it with that given by Dante. The Ottimo and Benvenuto da Imola copy Della Lana with little change, both giving the positions of Saturn, Jupiter, and Mars in degree and sign, but the sun only as near the beginning of Aries, Venus in Pisces, and Mercury in Virgo. (It is astonishing that neither should have noticed this gross error.) Benvenuto boldly adds that the moon was in Libra, doubtless because Dante’s description so required it at the beginning of his poem.

Nor do these early commentators seem to feel any difficulty about the date on which the Vision began. From _Inf._ i. 38-40 they generally conclude that it was the day of the equinox, which they say vaguely fell in the middle of March “mezzo Marzo,” and from _Inf._ xxi. 112-114 all except Boccaccio (who interprets March 25) take it to be Good Friday.[556] No discrepancy seems to have been felt here: they merely remark that in 1300 Easter fell in March, and more than two hundred years passed before anyone pointed out that this was wrong.

------------------------------------------------------------------------ [556] Moore, _Studies in Dante_ III. p. 146. ------------------------------------------------------------------------

At last a work appeared in 1554, called “_Del Sito, Forma, et Misure dello Inferno di Dante_,” in which the author, Giambullari, remarked that according to astronomical calculations the Paschal Moon was not full on the night between Thursday and Good Friday in 1300, but on the morning of April 5th. This excited a good deal of interest, and many theories have since been put forth to reconcile Dante’s astronomical data with the facts of the year 1300.

Dr. Moore thinks the date of entering the Inferno was Good Friday, April 8, 1300, but that Dante uses instead of the real moon the ecclesiastical moon, which, as we know, is a conventional body revolving according to Meton’s cycle, and sometimes appearing on tables as full two or three days before or after the real Full Moon. Dr. Moore finds that this ecclesiastical moon, was full on April 7, 1300.[557] But would Dante trouble about the ecclesiastical moon, and would his readers know anything about it? Its only use was for determining Easter, and this was done for the people by the Church. The real moon was extremely important for astrologers, for whose benefit Tables and Almanachs were chiefly drawn up; the real moon was useful to everyone as light-giver and time recorder. It is surely inconceivable that a Florentine who wished to arrange a midnight festival, or to start on a night-journey, would consult a calendar to find out on what date the _ecclesiastical_ moon would be full! And the ecclesiastical moon does not alter the position of Venus.

------------------------------------------------------------------------ [557] “The Astronomy of Dante,” in _Studies_ III., and _Time References in the Divina Commedia_. ------------------------------------------------------------------------

According to another suggestion, Dante followed a tradition as to the position of all the “seven planets” at the Creation, and for this reason not only was his sun in Aries, but the moon full and opposite, and Venus in Pisces. Venus is said to have this position in a picture of the Creation in a Church at San Gemignano.[558] Compare also Milton’s moon at her creation:—

------------------------------------------------------------------------ [558] Note on _Purg._ i. 19-21 in the “Temple” edition of Dante.

“ ... Less bright the moon,
But opposite in levelled west, was set,
His mirror, with full face borrowing her light
From him.”[559]

[559] _Par. Lost_ vii. 375-378. ------------------------------------------------------------------------

Or again, it is sometimes held that the day and all the celestial positions are ideal. Dante means us to understand that the first day of his Vision was Good Friday, but without troubling as to what day it fell on in 1300; the equinox and the full moon are naturally connected with Good Friday, since they determine Easter; Venus is connected with the idea of dawn, and when the Sun is in Aries the morning star may well be in Pisces.

Either of these views might be correct, and no one will dispute a poet’s right to arrange his skies as he thinks fit, if he is consistent with them, as Dante was. But how did these positions, if they are purely imaginary, come to coincide exactly with the real positions of 1301?

If we examine the positions of 1301, and accept nothing that is doubtful in Dante’s own words, what does the coincidence amount to? Saturn was near Regulus, but he was also in the forepart of Leo in 1300, and we are not sure that Dante means more than this; Mars was in Leo, but we are not sure that Dante wanted him there;[560] the moon was full on the morning of March 25, but we are not sure whether Dante means March 25 or Good Friday. Venus was a morning star in Pisces, and this till very lately was the one astronomical fact incontestably in favour of 1301 and against 1300.

------------------------------------------------------------------------ [560] See p. 407. ------------------------------------------------------------------------

But in 1908 there was printed in Florence, for the first time, a mediæval Almanach, which suggests so simple an explanation of this most striking coincidence that it seems to leave nothing more to be said for the 1301 hypothesis. This Almanach, which has been published under a title which perhaps takes things a little too much for granted—_Almanach Dantis Aligherii_—was compiled by a learned Jew, Jacob ben Machir ben Tibbon, who was born in Marseilles about 1236, and died at the beginning of the fourteenth century. Using the Toledan Tables, he constructed this so-called perpetual almanach, which gives the positions of sun, moon, and planets, at intervals of a few days for whole cycles of years. Each has a cycle of a different length, that of Venus for instance being 8 years, as on the Babylonian tablets of ephemerides; and at the end of each cycle nearly the same positions come over again. It was written in Hebrew, and translated into Latin by an unknown author, and must have been popular, since there were an immense number of Latin MSS. in the fourteenth century. In the original, all the cycles begin in 1301, but in the Latin they begin in 1300, _except the cycles of Venus and the sun, which begin in 1301_. Yet 1301 is not written over the first column for Venus, but merely 1, or nothing at all, or even in some copies 1300, and in both the Hebrew and Latin prefaces the beginning of all the cycles is stated to be 1300.[561]

------------------------------------------------------------------------ [561] Preface to _Almanach Dantis Aligherii_, Boffito and Melzi d’ Eril. ------------------------------------------------------------------------

If, therefore, Dante looked up the position of Venus in this almanac, he would very naturally take the 1301 positions for 1300, and he would find that Venus was in Aquarius throughout March, until the 27th, when she passed into the sign of Pisces, and therefore was a morning star during the whole month and also in April. And he would find that Saturn was in the 7th and 8th degrees of Leo in March and April 1300 (which was very nearly correct).[562]

------------------------------------------------------------------------ [562] It is important to observe that this suits the description of the “Lion’s breast” better than the 20th and 21st degrees (Almanach positions for 1301), if Dante, as usual in the _Divina Commedia_, identifies the constellation with the sign. ------------------------------------------------------------------------

It appears then that while certain expressions used in the _Divine Comedy_ prove clearly that 1301 is not the year assumed as the date of the Vision, the astronomical argument in favour of it is not strong enough to be convincing, especially in the light of this recent discovery.

Granting that 1300 was the year, what was the day? Probably not March 25, for the early commentators, excepting only Boccaccio in one passage, are all in favour of Good Friday, and Dante might see in the Almanac that the moon was not full on that date. But neither was she full on the actual date of Good Friday, which fell on April 8 in 1300; moreover the sun was then so far advanced in Aries that seven days later, when Dante describes it as a little past the equinox, it would really have been in Taurus. The third and only possibility is to accept the theory that his moon and his day were ideal; that is, he simply assumed Good Friday and a full moon to occur together soon after the equinox, with which both are so intimately associated. The date of Easter is not given in the old almanac, and we have seen that the early commentators who knew that the equinox fell in “mezzo Marzo”[563] were content to accept Easter as falling in that month also. We must not forget the convenience of an equinox and a full moon for simplifying the time references also.

------------------------------------------------------------------------ [563] The middle of March. ------------------------------------------------------------------------

We conclude, then, that the year chosen by Dante was 1300 (as has been most generally believed), and the day Good Friday, which he assumes to have fallen about a week after the equinox, and at a time of full moon. Saturn in his poem, and also in fact, was in Leo; Venus was not actually a morning star, nor in Pisces, but he may have been led to assign this position to her through an error in a contemporary almanac.

I must confess to a great feeling of disappointment in coming to the conclusion that Prof. Angelitti’s enticing theory must be rejected, but a careful study of Dante’s own words, and Prof. Boffito’s discovery of the “Almanach perpetuum ad annum 1300 inchoatum” seem to leave no other choice. Last April,[564] when helping to photograph Halley’s Comet in beautiful early dawns, this problem was much in my mind. Venus once more had the Fishes in her train, and oddly enough Good Friday had fallen on March 25! I could not help wishing that these things had happened in 1300 as well as in 1910!

------------------------------------------------------------------------ [564] This was written in 1910. ------------------------------------------------------------------------

If in spite of all arguments to the contrary, any readers are convinced that Dante’s celestial positions were taken from the real skies, it remains to them to imagine that he saw them in March of 1301 and wove them into the narrative of his poem, although for some reason he adopted another date.

The following tables (pp. 425-26) summarize the foregoing pages. It will be noted with what appropriate symbolism Dante enters Hell on the evening of Good Friday, spends that night and the whole of Saturday in the depths, and rises out of them on Easter Day before the dawn.

For although he reaches Earth’s centre on Saturday evening by Jerusalem time, the change of hemisphere there makes his time suddenly go back twelve hours, so that it is again Saturday morning, and he spends the day and night of Saturday (Purgatory time) in climbing to Earth’s surface.

DAYS OF THE VISION AND POSITIONS OF THE SUN, MOON, AND PLANETS.

Summary.

_Arguments for 1300 or 1301._
_From Expressions and Incidents in the D.C._

The Astronomical Data.

(_True Equinox, March 12. Ecclesiastical, March 21.
Traditional, March 25_).

Early commentators understand Good Friday, not March 25.

_VII. THEORETICAL AND SPECULATIVE ASTRONOMY._

“Thou shalt learn the burning nature of the pure
clear sun, thou shalt hear the wandering nature
of the round-eyed moon, and thou shalt learn of
the surrounding heaven, whence it arose, and how
Necessity guiding it compelled it to hold fast the
bounds of the stars.”
_Parmenides._

1. THE SPHERES.

Dante’s astronomical phenomena, though they are just the same that are familiar (or ought to be familiar) to us, have led us into some strange by-ways, because they are so intimately connected with his works of imagination. His astronomical theories, by which these phenomena were explained, will also take us into paths which are now seldom trodden by astronomers or others, because mediæval astronomy was mingled with magic, with metaphysics, and with religion, in a way which seems very strange to us.

The second treatise of the _Convivio_ has for its text the Ode which is quoted in _Paradiso_ viii. 37, “Voi che intendendo il terzo ciel movete.”[565] When speaking of the literal meaning of this Ode, Dante takes the occasion to discourse on the system of astronomy which he had learned, and describes how all the apparent movements of the heavens are explained by postulating the existence of spheres and epicycles, entering with special detail into the system of Venus, the third heaven; and later on, when expounding the allegorical meaning of the Ode, he draws an elaborate comparison between the spheres and the different branches of science and philosophy, in which he incidentally gives his readers a good deal of information about the heavens.

------------------------------------------------------------------------
[565]
“Oh ye whose intellectual ministry
Moves the third heaven.”
(_Carey_).
------------------------------------------------------------------------

From this interesting treatise, therefore, as well as from many scattered passages in all his works, we learn what Dante thought were the real movements of the heavenly bodies, their dimensions, their nature, and the forces which move them; and it forms a valuable commentary on the _Paradiso_, in reading which he supposes us to understand the elements of the Ptolemaic system, and the ideas of the philosophers and the Fathers of the Church concerning the organization of the Universe.

Of these ultimate truths concerning the heavens, Dante says, very little can be known, but the little which is within the reach of human reason, gives more delight (as Aristotle says) than the abundance and the certainty of other things easier to be understood.[566] This thought finds an echo in the _Paradiso_, where the poet reminds us of the beautiful order to be found throughout the universe, and invites us to contemplate the skill of the architect as shown in the movements of the planets.[567]

------------------------------------------------------------------------ [566] _Conv._ II. iii. 8-14.

[567] _Par._ x. 1-12. ------------------------------------------------------------------------

Dante knew that great men in ancient days had speculated on the possibility that it was Earth, and not the skies, that moved in the diurnal period, but the balance of authority was against them, and they had been confuted by the Master of those who KNOW,[568] that glorious philosopher to whom Nature most fully revealed her secrets,[569] Aristotle. In Treatise III. of the _Convivio_ he gives a clear and concise account of the theory of Philolaus, and of what he understood to be the theory of Plato.[570] In the former he seems to have been struck with the deduction that, if Fire were at the centre of the Universe, the real motion of fire on Earth, which to us appears always to ascend, would in reality be a descent towards its own place at the centre.

------------------------------------------------------------------------ [568] _Inf._ iv. 131.

[569] _Conv._ III. v. 54-56.

[570] _Conv._ III. v. 29-52. See Part I. of this book _Pythagoras and his Followers_, and _Plato_, for a description of their astronomical systems. ------------------------------------------------------------------------

Both these hypotheses he had evidently learned from Aristotle’s _De Cælo_,[571] and when thus presented they seem entirely fanciful; so although Dante had reverence for both Pythagoras and Plato it is not surprising that he rejected the systems of both. He adds that it is not his intention to recount here the arguments by which Aristotle confutes them and establishes the truth: it is enough for his readers to know, on so great an authority, that the earth is fixed, and does not revolve, and is at the centre of the World.

Dante has to confess reluctantly that Aristotle made two mistakes in his astronomy: he said that there were only eight spheres, those of the seven planets, and that of the stars, “e che di fuori da esso non fosse altro alcuno;”[572] also he placed the heaven of the sun immediately above that of the moon, that is to say second in order, counting from Earth outward. Aristotle’s loyal admirer hastens to add that these serious mistakes “questa sua sentenza così erronea”[573] are explicable and excusable because, as Aristotle himself shows in the _Metaphysics_, when he treated of astrology he was merely following the opinions of others. That is to say, he took his facts from others, and they cannot all be depended upon, but his philosophical deductions are his own, and are never in error. In the above question of the possible movements of Earth, we saw (pp. 101-2) that Aristotle’s arguments were almost entirely drawn from metaphysics.

------------------------------------------------------------------------ [571] See Part I. “Aristotle.”

[572] “And that outside the latter there was no other.” _Conv._ II. iii. 24, 25.

[573] “This entirely mistaken opinion of his.” _Ibid._ 28. ------------------------------------------------------------------------

There have been many opinions regarding the number and the positions of the spheres, Dante says, but the truth about them has at length been found. The scheme which he expounds is that of Ptolemy, modified by the Arabs and adapted to the doctrines of the Church by Christian writers. In the _Vita Nuova_ he almost seems to imply that the nine moving spheres form an article of faith. “Secondo Tolommeo e secondo la Cristiana verità, nove siano li cieli che si muovono.”[574]

------------------------------------------------------------------------ [574] “According to Ptolemy and according to Christian Truth, nine is the number of the moving heavens.” _V. N._ xxx. 16-18. ------------------------------------------------------------------------

Quoting from Albertus Magnus, or Averroës, he apparently credits Ptolemy with the discovery of precession, for he says that it was Ptolemy who added a ninth sphere to the eight of Aristotle, because he perceived that otherwise the outer sphere would have a double movement, and so he felt obliged to assume a sphere beyond the star sphere which should have only the one simple motion of the diurnal east to west revolution. The period of this revolution (the sidereal day) Dante gives as 23 hours and ¹⁴/₁₅ths of an hour, “grossamente assegnando,”[575] _i.e._ 23 hours 56 minutes, which is the correct value ignoring the 4 seconds. We know that it was not Ptolemy in fact who thought it necessary to add a ninth sphere; he was not sufficiently interested in spheres, since to him they were only mathematical abstractions: but the Arabs of Baghdad noted that he had added another _movement_, the discovery of Hipparchus; and they, accepting the spheres as material instruments of celestial motions, felt obliged to assume the existence of the Primum Mobile or 9th sphere.

That Dante should believe the spheres to exist as actual entities was inevitable, for his principal authorities, Greek, Arab, and Christian, all taught this. And there is abundant evidence that he did think of them thus. He calls them bodies:—“omnia corpora,”[576] “questi corpi grandi,”[577] “cerchi corporai,”[578] “il maggior corpo,”[579] etc. They are transparent, one sphere not obstructing the light from another;[580] and composed of æther, “questo etera tondo.”[581] They have a certain thickness, and would be visible if near enough, for Dante speaks of the inner margin of the Primum Mobile, and says that it was too far above him for him to have seen it yet, when he was in the Star Sphere.[582]

------------------------------------------------------------------------ [575] “Roughly speaking.” _Conv._ II. iii. 36-48.

[576] “All bodies.” _Ep._ x. 445.

[577] “These vast bodies.” _Par._ viii. 99.

[578] “Material circles” (here compared with the Angels, who are purely spiritual). _Par._ xxviii. 64.

[579] “The greatest body.” _Par._ xxx. 39.

[580] _Purg._ iii. 29, 30.

[581] “This rounded ether.” _Par._ xxii. 132.

[582] _Par._ xxiii. 112-117. ------------------------------------------------------------------------

He gives the order of the eight heavens as in Ptolemy, and adds the ninth, which is only perceived by the diurnal movement of which it is the cause; and it is called by many the Crystalline, that is, the diaphanous or completely transparent Heaven.[583] The order of these spheres has been discovered by observation and reasoning, with the use of the principles of Perspective, Arithmetic, and Geometry. Dante gives as an instance the experience of Aristotle, who with his own eyes saw the moon pass below Mars, and so hide it for some time; and he mentions also how in eclipses it is evident that the moon is below the sun (_i.e._ nearer to us).[584]

To these nine spheres of the astronomers, the Catholic Church, “which cannot lie,” adds a tenth, the Empyrean Heaven, which means the heaven of flame or light, and is the abode of the blessed spirits and of God Himself.[585] And here Dante is able to give himself the pleasure of adding that Aristotle seems to have been of this opinion also; “Ed anco Aristotile pare ciò sentire, a chi bene lo intende, nel primo _Di Cielo e Mondo_.”[586] He is no doubt alluding to what Aristotle says about the existence beyond the finite universe.[587] The whole passage is thus translated in the “Temple” Dante:[588] “Nor is there any change of any of those things which are ranged above the outmost rotation, but they are unchangeable and passionless, enjoying the superlative existence, and passing in absolute self-sufficiency their eternal life.”

------------------------------------------------------------------------ [586] “And Aristotle also, to one who rightly understands him, seems to mean the same thing, in his first book of _The Heaven and the Earth_.” _Conv._ II. iv. 32-34.

[583] _Conv._ II. iv. 1-13.

[584] _Conv._ II. iii. 52-65.

[585] _Conv._ II. iv. 13-16, 30-32. See also _Ep._ x. 448-452.

[587] See p. 97.

[588] _The Convivio of Dante_, “Temple” Edition, note on II. iv. ------------------------------------------------------------------------

The ninth sphere rotates on two poles, which are absolutely fixed, “fermi e fissi e non mutabile, secondo alcuno rispetto,”[589] the eight within it have each two poles which are only relatively fixed (for they move with the movement of the Primum Mobile), and every sphere has an equator, every point on which is equally distant from the two poles of rotation, as anyone may see who will turn round an apple, or any other spherical thing. Any point on the equator moves more quickly than any other point on the sphere, and each part moves more quickly the nearer it is to the equator, more slowly as it is far from it and nearer to the pole, since all the circling is done in the same time, and some parts have a greater, and some a less distance to go, according to their distance from the equator. Dante adds that the nearer any part of a heaven is to its equator, the nobler it is compared with its poles, for it has more movement, and more actuality, more life, and more form, and it touches more of the heaven just above, and in consequence is more noble.[590]

------------------------------------------------------------------------ [589] “Firm and fixed and not moveable, from any point of view.” _Conv._ II. iv. 50, 51.

[590] _Conv._ II. iv. 68-75. ------------------------------------------------------------------------

Besides these ten heavens there are others which, strictly speaking, should be included in the number: these are the little spheres which are called “epicycles” by astronomers, and they also have equators and poles of rotation, and are fixed on the large spheres, or heavens. Dante does not enter into any particulars about these, but only mentions (as belonging specially to the subject in hand) that the brilliant star of Venus is carried “on the back” of an epicycle, which is itself fixed on the back of the third Heaven.[591] The apparent movement of Venus is therefore compounded of no less than four movements: that of her epicycle, of her whole heaven (the “deferent” Dante does not name, probably as introducing too technical a word), of the west to east motion of the star sphere (precession), and the diurnal. The epicycle of Venus is also called in this treatise, as we have already seen, “quello suo cerchio che la fa parere serotina e mattutina, secondo i due diversi tempi,”[592] and the “terzo epiciclo”[593] is referred to in _Par._ viii. 3.

------------------------------------------------------------------------ [591] _Conv._ II. iv. 78-104.

[592] “That circle of hers which makes her appear as evening and morning star, according to the two different periods.” _Conv._ II. ii. 3-5.

[593] “Third epicycle.” ------------------------------------------------------------------------

A little further on in the same treatise, Dante tells us the periods in which all these nine spheres revolve. It is an interesting passage, and illustrates the poet’s vivid way of bringing home to his own mind and those of his readers the effects of the different celestial motions.[594] The ninth sphere, which is the Crystalline or Primum Mobile, causes by its daily revolution the daily revolution of all the other spheres, which are within it; it is, as Beatrice says, “costui, che tutto quanto rape l’altro universo seco.”[595] Therefore if we imagine it possible for the motion of this Crystalline Heaven to cease, what will be the effect on the motions of the other heavens? Obviously their diurnal movement from east to west will cease, and we shall only see them revolving, each in its own period, from west to east. There will be no alternation of day and night, or rather, there will be one long day of six months, and one long night of the same length, in any given place all over the earth. In the same way the moon will be invisible for half the month; and all the planets will be invisible to us for half their periods; and as Dante believed only the known hemisphere of Earth to be inhabited, he could say that during one half of each period no one would see the planet at all. He enumerates the half period in each case, as follows:—

------------------------------------------------------------------------ [594] _Conv._ II. xv. 132-155.

[595] “That one which sweeps the whole of the rest of the universe along with it.” _Par._ xxviii. 70, 71. ------------------------------------------------------------------------

_Half Period Whole Period given by Alfraganus_
“_Planets._” (_approximate_) (_El. Ast. ch. xvii._)
_given by Dante. Years Months Days_

Saturn 14½ years 29 5 8
Jupiter 6 ” 11 10 14½ about.
Mars about a year 1 10 22 nearly.
Sun 182 days, 14 hrs. ... 365¼ nearly.
{about the same
Venus { as the sun. ... ”
Mercury ” ” ... ... ”
Moon 14½ days ... (nearly) 27, 7¾ hrs.
(Paris edition, 29 days, 12¾ hrs.)

If we compare these with the zodiacal periods given by Alfraganus, we see that Dante has taken those of Saturn, Jupiter, and Mars at the nearest whole number of years and halved them, but with the sun he seems to have used that more exact value with which we have already seen that he was acquainted. For to divide the 365¼ days of Alfraganus by 2 would have given him exactly 182 days 15 hours; but dividing 365 days 5 hours, and neglecting minutes gives 182 days 14 hours. The large oscillations of Venus and Mercury would make their periods of visibility very irregular, but the mean period would be, as Dante says, about the same as that of the sun. He has made a slip with the moon, for of course it is her sidereal period of 27 days 7¾ hours which he should have taken, giving a half period of less than 14 days, whereas he has evidently taken the mean synodic period of 29 days 12¾ hours, and ignored the hours. All the printed editions of Alfraganus give the sidereal period in this passage, except the Paris edition of 1546; but that gives the synodic,[596] so it doubtless appeared on some mediæval MSS. Dante must have had the misfortune to possess or consult one of these.

------------------------------------------------------------------------ [596] Toynbee, “Dante’s Obligations to Alfraganus in _Vita Nuova_ and _Convivio_,” in _Romania_ xxiv. 95. ------------------------------------------------------------------------

As for the stars, one third of their sphere would not yet have been seen. This is not difficult to understand if we remember what the movement of the star sphere was supposed to be, and how long it was since man had first begun to look upon it, according to Dante’s chronology. The movement which makes the equinoctial point shift its place among the stars was thought to be a movement of revolution of the whole star sphere, and its rate to be one degree in a century; the age of the world, we learn from _Par._ xxvi. 118-123, was over sixty centuries when Dante wrote. For Adam said that he had spent 930 years on Earth and 4302 in the Limbo, so that Dante evidently counted 5232 years from the Creation to the Crucifixion, that is (5232-33 =) 5199 to the beginning of our era at the birth of Christ, which is the date given by Orosius; adding 1300 years to this, we find that the age of the world in Dante’s day was more than 6000 years. Therefore the star sphere had revolved, since the beginning of the world, through more than 60 degrees.

The first inhabitants of this earth saw half the starry sky or 180°, and since then it had revolved through 60°, which together is equal to 240°; therefore there would still remain 120°, or one third of a revolution, to be made to complete the whole 360°, and bring every part of the star sphere into view. Just before this passage Dante had expressed the same idea in another way. This movement proper to the star sphere, he says, will never have an end, for the end of a revolution is to return to the same point; and this heaven will never do so, for since the beginning of the world it has turned through a little more than the sixth part of its whole revolution (60° = ⅛ of 360°), and we are already in the last age of the world, and indeed are awaiting the consummation of the celestial motion.[597]

------------------------------------------------------------------------ [597] _Conv._ II. xv. 108-118. ------------------------------------------------------------------------

If the premises be granted, the conclusions are correct. As regards sun, moon, and planets, they are correct even from the point of view of modern knowledge. For if the diurnal motion (that is Earth’s rotation) were to cease, while her other motions, and those of the rest of the solar system remained as at present, her motion round the sun would cause it to rise and set once in a year, and the appearance of moon and planets also would be as described. The vastly distant stars would have no appreciable motion, save that caused by precession, for if the earth revolved round the sun without turning on her axis, the same stars would always remain on the meridian at any given place. Precession, however, would not have the result which Dante supposed. He considered it to be a rotation of the star sphere, but we know that it is merely a nodding. Hence at any given place a star at the pole would describe, in the course of centuries, a small circle in the sky, and those at the equator would move in short lines first north and then south, while stars between would move in ellipses which become narrower as they approach the equator. All round the horizon, therefore, there would be slight very slow changes, bringing a few fresh stars into view, and causing others to disappear. The whole amount of the sky actually seen would vary but little, even if the world should last much longer than Dante expected.

Dante evidently took his value of precession from Alfraganus, for he was one of the few Arab astronomers who accepted Ptolemy’s erroneous figure.

In the _Paradiso_, as the poet mounts with Beatrice from sphere to sphere he mentions the number of each one in its order. The moon is “la prima stella,”[598] Mercury “il secondo regno,”[599] Venus “il terzo ciel,”[600] the spirits met in the sun are “la quarta famiglia,”[601] Mars is “questa quinta soglia,”[602] and “più levato”[603] than the last heaven, Jupiter is the “stella sesta,”[604] Saturn “il settimo splendore.”[605] The starry heaven is alluded to as “la spera ottava.”[606] The Primum Mobile is “il ciel velocissimo,”[607] “il maggior corpo.”[608] The Empyrean, “il ciel ch’ è pura luce,”[609] is called “l’ultima spera,”[610] but this has no limits and no movement, and therefore no poles:—

------------------------------------------------------------------------ [598] “The first star.” _Par._ ii. 30.

[599] “The second realm.” _Par._ v. 93.

[600] “The third heaven.” _Par._ viii. 37.

[601] “The fourth family.” _Par._ x. 49.

[602] “The fifth threshold.” _Par._ xviii. 28.

[603] “More lofty.” _Par._ xiv. 85.

[604] “Sixth star.” _Par._ xviii. 68, 69.

[605] “The seventh splendour.” _Par._ xxi. 13.

[606] “The eighth sphere.” _Par._ ii. 64.

[607] “The swiftest heaven.” _Par._ xxvii. 99.

[608] “The greatest body.” _Par._ xxx. 39. Compare _V. N._ xlii. 47. “Oltre la spera che più larga gira,” (“beyond the sphere which has the largest circle).”

[609] “The heaven of pure light.” _Par._ xxx. 39.

[610] “The last sphere.” _Par._ xxii. 62.

“ ... In quella sola
E ogni parte là dove sempr’ era;
Perchè non è in loco, e non s’impola.”[611]

[611]
“ ... Within that one alone
Is every part where it has always been;
For it is not in space, nor turns on poles.”
_Par._ xxii. 65-67. (_Longfellow._)
------------------------------------------------------------------------

In _Conv._ II. iv. 35-39 it is thus described:—

“Questo è il sovrano edificio del mondo, nel quale
tutto il mondo s’inchiude; e di fuori dal quale
nulla è; ed esso non è in luogo, ma formato fu
solo nella Prima Mente, la quale li Greci dicono
Protonoe.”[612]

------------------------------------------------------------------------ [612] “This is the sovereign edifice of the world, in which all the world is enclosed, and beyond which is naught; and it exists not in space, but received form only in the Primal Mind, which the Greeks call Protonoe.” See also _Ep._ x. 442-447. ------------------------------------------------------------------------

We must remember, however, that the spheres are sometimes counted in the other direction, from the outermost to the innermost or lowest, and therefore this “ultima spera”[613] is elsewhere spoken of as “il primo cielo,”[614] “il primo giro,”[615] “cœlum primum.”[616]

------------------------------------------------------------------------ [613] “Last sphere.”

[614] “The first heaven.” _Purg._ xxx. 1.

[615] “The first circle.” _Par._ iv. 34.

[616] “First heaven.” _Qu._ iv. 7. ------------------------------------------------------------------------

2. THE SPHERES AND THE FOUR ELEMENTS.

The pure region of the spheres, “il paese sincero,” is immortal as the spirits themselves;[617] but below the lowest celestial sphere (“la celestial c’ha men salita” _Par._ iv. 39) all is mortal and transitory, as the Greeks and the Latin poets had said. This is expressed in the Letter to Can Grande, when Dante contrasts the spheres (cœlum) and the elements, and says: “illud incorruptibile, illa vero corruptibilia sunt.”[618] It is also implied in Virgil’s address to Beatrice:

------------------------------------------------------------------------ [617] _Par._ vii. 130-132 compared with 67, 68. See also _Par._ i. 64 and 76.

[618] _Ep._ x. 435-437. ------------------------------------------------------------------------

“O donna di virtù, sola per cui
L’umana specie eccede ogni contento
Da quel ciel che ha minor’ li cerchi sui.”[619]

------------------------------------------------------------------------
[619]
“O Lady of Virtue, thou alone through whom
The human race exceedeth all contained
Within the heaven that has the lesser circles.”
_Inf._ ii. 76-78. (_Longfellow_).
------------------------------------------------------------------------

It is only through the spiritual teaching which Beatrice symbolizes that the human race can rise above all that is comprised within the heaven of the smallest sphere. And it is taught by Beatrice herself when, in the heaven of Mercury, she discourses on the mysteries of the creation and redemption. The angels, the souls of men, and the spheres, were created directly by God, she says, and are therefore immortal, but the elements, water, fire, air, earth, and all things that are formed out of them, also the souls or living principles of all animals and plants, were created through intermediate instruments and are mortal. These intermediate instruments are the heavenly bodies. Pure or inchoate matter was created at the beginning by God, and a power infused into the stars to give it form.[620]

------------------------------------------------------------------------ [620] _Par._ vii. 124-143. Compare with Plato’s account of the creation of living beings (Part I., _Plato_). ------------------------------------------------------------------------

Dante follows the classics and agrees with his contemporaries in arranging the four elements in four spheres, which are below the celestial spheres. The sphere of Fire is immediately within that of the moon, below this comes Air, then Water, and lastly the solid sphere of Earth. The contrast between Fire which constantly tends to rise towards the moon, and Earth which sinks towards the centre of the universe, is a favourite thought with him;[621] and lightning striking the earth is described as fleeing its proper place.[622] Aristotle seems to have regarded the four elements as flowing into one another, so that these lowly spheres beneath the moon were not sharply divided, but his mediæval disciples, following the Greek idea to its logical conclusion, conceived them with boundaries as definite as those of the celestial spheres. “Exhalations” could pass from one to another, but each particle of every element tended always to revert to its own place, which was distinct from the others.

------------------------------------------------------------------------ [621] _Par._ i. 115, 117; _De Mon._ I. xv. 38-41; and III. vii. 30, 31, etc.

[622] _Par._ i. 92, 130-134. ------------------------------------------------------------------------

And here they encountered a serious difficulty. If the sphere of water is naturally higher than that of earth, how comes it that in one quarter of the globe land rises above the ocean? It was recognised as necessary that this should happen in some part of the world, in order for an opportunity to be given for the elements to combine and to form all those substances and all those living creatures, including man, for which this earth was prepared; it was also agreed that the celestial spheres were the agency by which the Creator had first chosen to “let the dry land appear,” and by which it was maintained above the ocean; but the exact nature of this force and the way in which it acted was a question sometimes discussed. Albertus Magnus was of opinion that the rays of the sun and the stars, which had more power in the temperate and tropic zones than in the arctic, had here dried up the ocean, and he quotes Albumassar’s statement that this proves the existence of land on the southern side of the equator also. Ristoro, on the other hand, believed that the waters had been drawn up and rolled back from the habitable earth, and he attributes the elevating force to the stars of the north, bringing in his favourite theory that in this hemisphere they are far more numerous, and the constellations, from their upright position, are far more powerful than in the south.

He compares this lifting force of the stars to the attractive power of a magnet over iron, and argues that it must be the waters which are drawn away from the earth, not the earth which is lifted above the water, because the starry influence in its downward course would meet first the sphere of water, and moreover it is lighter and easier to move than Earth. He also thinks that the presence of springs on mountain tops is to be explained by the fact that the ocean is preserved at a higher level, hence water percolating through the porous land, as through a sponge, is forced up to its utmost height.

It does not seem as if Dante had paid much attention to this problem when he was writing the _Convivio_, for although he calls the habitable part of the earth “the uncovered land,” “la terra discoperta” (_Conv._ III. v. 73), he speaks of Earth and ocean as if they formed a globe together, “Questa terra ... col mare è centro del cielo,”[623] in the manner of Alfraganus, “Inter sapientes convenit, terram unà cum aqua globosam esse.”[624] But if we may believe that Dante is the author of the _Quæstio de Aqua et Terra_—a belief shared by many experts—he became greatly interested in the problem later on. According to the introduction and the final colophon, he attended a discussion on the subject and joined in it himself, when in Mantua, and afterwards in Verona less than two years before his death he wrote and read in public a Latin treatise in which his arguments and conclusions are set forth.

------------------------------------------------------------------------ [623] “This earth, together with the sea, is the centre of heaven.” (_Conv._ III. v. 63-65.)

[624] “It is agreed among learned men that earth and water together form a globe.” (_El. Ast._ iii.). ------------------------------------------------------------------------

He seems to have had in mind Ristoro’s book, and while refuting some of the conclusions agrees with others. As a thirteenth century scholar he admits, as a matter of course, that the centre of the earth is the centre of the Universe and the goal towards which all heavy things tend; that earth as the heaviest element ought to be everywhere nearest this centre, while water ought to occupy the nobler place above it, that is, nearer to the most noble sphere of all which envelops all the others (the Empyrean). He also reasons, in true Dantesque and true mediæval fashion that there must be some place in the universe where all the elements may meet and mingle so that all potential forms of matter may be realized; otherwise the Mover of heaven, in whom all these forms (Plato’s Ideas) actually exist, would fail to give complete expression to his goodness, which is impossible.[625]

------------------------------------------------------------------------ [625] _Qu._ xviii. 28-54. This may be compared with _Par._ xxix. 13-18. ------------------------------------------------------------------------

The author of the _Quæstio_ denies, however, that this was accomplished by the removal of part of the sphere of water from the underlying earth. The ocean cannot have been drawn away and heaped up, he says, for water would always flow down again, being fluid and naturally seeking its own level; nor can the sphere of water be eccentric to that of Earth so that the latter emerges from it in one part. The reason for this is interesting since it implies a curious and apparently novel theory of gravity. Aristotle’s theory was that all heavy things tend by a natural law towards the centre of the universe, and therefore necessarily range themselves in spheres round it; the writer might therefore have made short work of Water’s eccentric sphere by stating briefly that it could not exist; instead of this, however, he suggests a new law of gravity, apparently invented on the spur of the moment, according to which everything which has weight tends towards the centre of its own circumference. If then earth and water had two separate centres, they would fall naturally in different directions, or as he puts it “to different _downs_.” Yet we know that the law of gravity is the same for both, and therefore their spheres must be concentric. The centre of the universe must be also the centre of the sea.[626] It had apparently been urged (perhaps in the discussion at Mantua) that since water follows the moon in the tides, its sphere may also imitate hers in being eccentric, but although Dante takes for granted that a connection between moon and tides is proved (and indeed it had been noted by the Greeks),[627] he replies that imitation in one particular need not imply imitation in all. Again, if the sphere of earth emerged from the sphere of water in the way proposed, the outline of the emergent earth must be circular, instead of which it is that of a half-moon, or nearly so, its width from east to west being much greater than its length from north to south.

------------------------------------------------------------------------ [626] _Qu._ xv. 10, 11.

[627] See p. 134. ------------------------------------------------------------------------

Dante has been blamed for assigning this shape to the emergent earth, but the comparison of Earth’s habitable quadrant with the illuminated quadrant of the moon is perfectly just, as we saw with Ristoro,[628] from whom Dante is perhaps quoting here. The qualifying “vel quasi”[629] is added because the truly habitable regions did not extend over the whole quadrant, but stopped short at the arctic circle.

------------------------------------------------------------------------ [628] See p. 247.

[629] “Or nearly.” _Qu._ xix. 61-63. ------------------------------------------------------------------------

The existence of springs on mountain tops is explained by the fact that water rises thither not in the form of water but of vapour. Another upholder of Ristoro’s theory that Water was rolled away from Earth seems to have brought forward as evidence that sailors can see distant land from the mast which is invisible from the deck, and that therefore it evidently lies below the ocean; but this is confuted by the true and well known explanation that it is the convex shape of the sea which hides the distant land. Our author adds to his other arguments, in the curiously casual way so characteristic of his age, the ordinary observation which would be the first to occur to us, and quite sufficient in itself, viz. that instead of seeing a great wall of ocean rising above our sea-coasts, we invariably see the coast rising above the sea.

His own idea is that though the sphere of Water in general rises above Earth, in one part of the northern hemisphere Earth has been drawn up above the ocean. Earth must be subject to an uplifting influence, as well as to the downward drag of gravity, just as man is susceptible to the influence of reason as well as to the sway of his lower passions. This uplifting influence is not inherent in Earth herself, an upward impulse would be contrary to her own nature; nor can it be in water, or air, or fire, since all these are homogeneous bodies, and their virtue is evenly distributed, so that they could not cause a local and partial effect. It must be therefore in one of the heavens, and it remains for us to enquire which.

It cannot be in the heaven of the moon, for in the moon herself resides whatever influence comes from her sphere;[630] and she goes as far south of the equator as she does north: therefore she would raise land beyond the equator as well as on this side, but this is not so.

------------------------------------------------------------------------ [630] Compare with _Conv._ II. vii. 88-100, where the poet says that the influence from each sphere comes on the rays of the planet in that sphere, also _De Mon._ III. iv. 139, 140. ------------------------------------------------------------------------

Then follows a passage of which commentators can make nothing as it stands:—

“Nec valet dicere quod illa declinatio non
potuit esse propter magis appropinquare terræ
per excentricitatem; quia si hæc virtus elevandi
fuisset in luna, (quum agentia propinquiora
virtuosius operentur) magis elevasset ibi quam hic.”[631]

------------------------------------------------------------------------ [631] “Nor does it avail anything to say that that declination could not take place because of approaching nearer the earth through eccentricity; for if this elevating virtue were in the moon, since agents act the more powerfully the nearer they are, she would elevate there rather than here.” _Qu._ xx. 65-71. ------------------------------------------------------------------------

Previous Next

Comments

Dante and the early astronomersChapter XVIII: Introduction (13)

0%36 min left in chapter