most esteemed, the methods of study pursued, and the results obtained,
by thirteenth-century scholars seeking to gain the ultimate perfection
of the soul.

Astronomy is frequently introduced, especially in the second and third
treatises. The Ode which forms the text of the second treatise is
that which is quoted by Charles of Hungary in _Par._ viii. 37—“Voi
che intendendo il terzo ciel movete,”[155] and it gives Dante the
occasion to speak first of the heaven of Venus, explaining Ptolemy’s
system of epicycles, and later of all the heavens in their order, and
the celestial bodies contained in them. The ode of the third treatise
contains the line “Non vede il Sol, che tutto il mondo gira ...”[156]
and upon this he hangs a complete little essay describing the movements
of the sun, and how they appear from different parts of the earth, as
well as a short dissertation on the question whether it is Sun or Earth
which actually moves.

[155] “Oh ye whose intellectual ministry
       Moves the third heaven.”—_Carey._

[156] “The sun sees not, though circling all the world.”

The Latin works, _De Monarchia_, _De Vulgari Eloquentia_, the
_Eclogues_, and the _Letters_, do not give much scope for astronomical
references; yet there are many similes drawn especially from the sun
and moon, and the thought of the spheres as instruments of God’s Will
in bringing about events on earth is constantly recurring. In the
curious work _Quæstio de Aqua et Terra_, Dante argues learnedly about
the spheres, the orbit of the moon, and her effect on the tides, and
the influences of the stars. The book purports to have been written at
Verona in 1320 as the outcome of a discussion in which Dante had taken
part as to the respective heights of land and ocean, a problem which
had been dealt with by Ristoro d’ Arezzo some forty years earlier. Its
authenticity has been questioned, partly under the mistaken idea that
facts such as gravity, the spherical form of Earth, and the connection
of tides with the moon were not known until much later; but as a matter
of fact the discussion is quite in the manner of Dante’s day, and no
facts or theories are put forward which he could not have learned
from books with which we believe he was acquainted.[157] The internal
evidence of his authorship is strong, and belief in it seems to be
gaining ground among experts.[158]

[157] The spherical form of Earth, and the action of gravity at the
earth’s surface, were commonplaces with the Greeks, as we have seen
in Part I. of this book. Posidonius, Strabo, and other classical
writers speak of the tides as following the revolution of the heavens,
and having periods similar to those of the moon; Albertus Magnus and
Aquinas ascribe them to the influence of the moon, and so does Dante
himself in _Par._ xvi. 83.

[158] See Moore, _Studies in Dante_, II. “The Genuineness of the
_Quæstio de Aqua et Terra_,” for a complete discussion of the question.

Finally, the _Divine Comedy_, the work of Dante’s maturity, which took
him so many years to write, and for which he had studied ever since he
closed the _Vita Nuova_ with the resolve to write more worthily one day
of Beatrice,[159] focuses in one unique and finished work the thoughts
and ideals, the knowledge and fancies, of the poet and his age. The
subject of the poem, taken in its literal sense, is cosmical, for it
describes a journey in which the author penetrates to the centre of
the universe, and passes from planet to planet until he reaches the
outermost sphere. Moreover, the journey is assumed to take a definite
space of time, and the passing of the hours by day and by night is
indicated by the successive positions of sun or stars, and the phases
and movements of the moon. The _Divine Comedy_ contains more than twice
as many allusions to the heavenly bodies as all the other works of
Dante put together.

[159] _V. N._ xliii. 3-7.

But we must discriminate in drawing conclusions from these
astronomical references so freely distributed in all Dante’s writings.
If he wrote the _Quæstio_, it is his only professedly scientific
work, written for scientific men, and astronomy is only brought in
incidentally. The _Convivio_, in which astronomical facts and theories
are set forth in much greater detail and fulness than elsewhere, was
a popular work meant for those who had no inclination, or else no
opportunity, for prolonged serious studies. We expect, therefore, that
technical details will be avoided. Still more will they be omitted in
the _Divine Comedy_ and other poetical works, where difficult problems
and pedantical accuracy would be most unsuitable. We can _infer_ the
knowledge which lay in Dante’s mind, behind his popular use of it in
literature; and we can often find an explanation in the prose of the
_Convivio_ for a slight allusion in the poetical works; but we must
not deal with any as if they were text-books, and set forth precisely
and completely all that Dante knew of his favourite science. It is
the poet’s artistic use of the astronomy of his day which merits our
admiration quite as much as the scholar’s proficiency.

This being premised, we may now proceed to quote from his works,
showing how he has dealt with first the facts, and secondly the
theories, of astronomy. Finally we shall be able to form a clear mental
picture of the universe as it was believed to exist by Dante, and not
only by his contemporaries but by his successors for many generations.

_V. OBSERVATIONAL ASTRONOMY._

    “The heavens declare the glory of God; and the
    firmament sheweth His handy-work. Day unto day
    uttereth speech, and night unto night sheweth
    knowledge. There is no speech nor language where
    their voice is not heard. Their line is gone out
    through all the earth, and their words to the end
    of the world. In them hath he set a tabernacle for
    the sun; which is as a bridegroom coming out of his
    chamber, and rejoiceth as a strong man to run a
    race.”

1. MOVEMENTS OF THE MOON.

Of all the seven sciences of the Trivium and Quadrivium, Astronomy,
Dante thought, was the noblest, and for two reasons. Aristotle had said
that a science is noble in proportion to the nobility of its subject,
and the certainty of its conclusions; and in both of these Astronomy
excels. Its subject is the Movement of the Heavens, and its certainty
is perfect. “E nobile e alta per nobile e alto suggetto, ch’è del
movimento del cielo: è alta e nobile per la sua certezza, la quale è
senza ogni difetto.”[160] If astronomers are sometimes mistaken, the
fault lies in them, as Ptolemy said, and not in the science.

[160] _Conv._ II. xiv. 244-217. “It is noble and lofty because of its
noble and lofty subject, which is the movement of the heavens; it is
lofty and noble because of its certainty, which is without flaw.”

This quotation from Ptolemy is from his book on “judicial
astronomy,”[161] and it may be that Dante was partly thinking of
astrological predictions, as he almost certainly was in the passage
that follows, where he adds that astronomy takes a long time to
learn, not only because of its great range, but because experience is
necessary to form a correct judgment. Nevertheless, it is probable that
by its flawless certainty he meant that unchanging laws govern the
celestial phenomena, so that they may always be predicted without error
when the laws are known.

[161] See p. 156.

His definition of astronomy was accurate, for it was not until the
middle of the nineteenth century that physical astronomy began to take
its place beside the old “astronomy of position,” and in Dante’s day
practically the only subject open to research concerning the heavenly
bodies was their movements. Of these, and especially the “prime motion”
of the diurnal revolution, he was vividly conscious. His favourite name
for the heavens is “wheels”—“le ruote magne,” “eterne ruote,” “stellate
ruote”;[162] and he often refers to them as a standard of motion. Thus
when with Beatrice he was rapt from the summit of Mount Purgatory, to
express the swiftness of their flight he says it was almost as rapid
as the movement of the sky—“veloci, quasi come il ciel vedete.”[163]
Constantine moving the capital of the Roman Empire eastwards is
described as turning the Roman Eagle contrary to the course of the
sky—“contra il corso del ciel,”[164] and the sky itself is described as
a sphere which is ceaselessly at play like a lively child:—

[162] “The great wheels,” “eternal wheels,” “starry wheels.”

[163] “Swift, almost as the heaven ye behold.” _Par._ ii. 21.

[164] “Against the course of the sky.” _Par._ vi. 2.

                           ... “la spera,
    Che sempre a guisa di fanciullo scherza.”[165]

[165]                         ... “That sphere,
    Which aye in fashion of a child is playing.”
                                _Purg._ xv. 2, 3. (_Longfellow_).

To Dante, as to the Greeks, it is not the unusual or startling that
appeals, but the unfailing harmony of the regular celestial movements.
Comets he mentions only twice, and shooting stars twice, eclipses seven
times; but there are scores of allusions to the rhythmical progression
of Sun and stars, Moon and planets. The skies were familiar to him
in all their daily aspects—sunset and dawn and radiant noons; cloudy
nights “sotto pover cielo,”[166] brilliant starlit nights, nights of
clear moonlight. He had seen the stars fade one by one, till at last
even the brightest vanished in the glow of dawn:—

[166] “Under a poor sky.” _Purg._ xvi. 2.

    “E come vien la chiarissima ancella
    Del sol più oltre, così il ciel sì chiude
    Di vista in vista, infino alla più bella.”[167]

[167] “And as advances, bright exceedingly,
       The handmaid of the sun, the heaven is closed,
       Light after light, to the most beautiful.”
                           _Par._ xxx. 7-9. (_Longfellow_).

he had watched for their first appearance in the evening twilight:—

    “E sì come al salir di prima sera
    Comincian per lo ciel nuove parvenze,
    Sì che la vista pare e non par vera....”[168]

[168]                      “As at evening hour
      Of twilight, new appearances through heaven
      Peer with faint glimmer, doubtfully descried.”
                              _Par._ xiv. 70-72. (_Carey_).

Numberless other passages and expressions will occur to every Dante
reader, proving how keenly he felt the beauty of the skies.

But they prove more than this. Other authors have felt and have
described poetically the beauties of the skies, but they often remember
imperfectly what they saw, or draw upon their imagination without any
knowledge of the celestial movements, and so fall into absurd mistakes.
The moon especially is a stumbling-block, and it is quite a rare thing
for a modern novelist to introduce one without making it do something
impossible. A new moon will rise at midnight, or a waning moon at
sunset; she has even been known to rise and then to set in the dark
hours of one short midsummer night;[169] and a well known author sees
her in two phases at the same moment: “the full moon rose, yellow _and
gibbous_!”[170]

[169] In Kenneth Grahame’s delightful book, full of sympathy with
Nature, _The Wind in the Willows_. The moon rose when it was “past ten
o’clock,” and “sank earthwards reluctantly and left them” before dawn.

[170] H. G. Wells, _The Time Machine_.

Dante’s moon does indeed give us a little trouble once or twice, but
he never makes flagrant mistakes of this kind. His consistency and
truth of description prove his knowledge of astronomy, and also imply
intelligent thoughtful watching of the celestial movements; for it
is notorious that book-knowledge, if unassisted by acquaintance at
first-hand with the facts of a subject like astronomy, will not save a
writer from glaring inaccuracies.

His allusions to the motions of the moon, both diurnal and monthly,
show plainly that he understood them well. His new moon appears in
the evening, his waning moon rises late at night and sets in morning
sunshine,[171] and his full moon comes on the meridian at midnight, for
when he wishes to describe her at her brightest, as a comparison with a
very brilliant light, he places her in a clear sky at midnight in her
mid-month.[172] In the middle of a lunar month the moon is full, and
being exactly opposite the sun will reach the meridian at midnight:
this therefore is the time when she gives all the light she possibly
can. In the _Quæstio_[173] Dante mentions that the moon does not move
in the celestial equator, but sometimes north of it, and sometimes an
equal amount south; in the _Convivio_ he indicates the length of her
period, and briefly describes her phases and their cause—“Ora luce da
un lato, e ora luce dall’ altro, secondo che ’l sole la vede.”[174]

[171] _Inf._ xv. 18, 19; _Purg._ xviii. 76-81; _Purg._ x. 14, 15, _Cf._
ix. 44.

[172] _Purg._ xxix. 53, 54.

[173] _Qu._ xx. 61-63.

[174] “Now she shines on one side, and now on the other, according to
the way the sun looks upon her.” _Conv._ II. xiv. 77-79.

Her position in the zodiac is mentioned several times. In one passage
he indicates a very brief space of time in the following curious way:—

    “Quando ambo e due i figli di Latona,
        Coperti del Montone e della Libra,
        Fanno dell’ orizzonte insieme zona,
    Quant’ è dal punto che il zenit inlibra.
        Infin che l’uno e l’altro da quel cinto,
        Cambiando l’emisperio, si dilibra,
    Tanto, col volto di riso dipinto,
        Si tacque Beatrice.”[175]

[175]
    “At what times both the children of Latona,
        Surmounted by the Ram and by the Scales,
        Together make a zone of the horizon,
    As long as from the time the zenith holds them
        In equipoise, till from that girdle both
        Changing their hemisphere disturb the balance,
    So long, her face depicted with a smile,
        Did Beatrice keep silence.”
                                _Par._ xxix. 1-8.

That is to say, when Sun and Moon (the children of Latona) are both
on the horizon, but one being in Aries and the other in Libra they
are opposite one another, the zenith for a moment holds them, as it
were, in balance; but the next moment one will drop below the horizon
while the other rises above it, thus changing from the visible to
the invisible hemisphere and _vice versa_, as each frees itself (“si
dilibra”) of the common horizon that girdled them. The pause of
Beatrice was as brief as the time during which sun and moon would thus
hang in the balance.

Yet, though Dante shows that he was familiar with the movements
and appearances of the moon, his allusions to her are cold and
comparatively rare. Unlike modern poets, moonlight does not seem to
have had any great fascination for him. In all his works there are
only fifty-one references to the moon, and far the greater number of
these are remarks about the measurement of time, or else her phases,
her markings, her share in causing eclipses etc. In all his short poems
(including those of the _Vita Nuova_ and _Convivio_) there are but two
references, and those as dry as possible. “Più lune”[176] is once used,
meaning several months, and in a sonnet which describes the influences
of each heaven on his lady, all he can find to say of the moon’s is “E
’l primo ciel di sè già non l’è duro.”[177]

[176] “Many moons.” _Canz._ xx. 89.

[177] “And the first heaven is not grudging to her.”—_Sonetto_ xxviii.

The chill of moonlight is spoken of as with a shudder on the hill of
Purgatory;[178] and its usefulness is recognized rather grudgingly
when Virgil remarks that yesternight the moon was full, and adds that
Dante must remember it, since it did him no harm in the depths of the
Forest.[179] It is true there is some beauty in the description of the
aurora which preceded moonrise[180] on the first night in Purgatory,
but Dante gives it an ugly name, and the waning moon when seen on the
following night, four days after full, is oddly compared to a bucket
in shape. Dante did not admire this gibbous form, for he instances
the outline of the moon when not quite full as an ignoble curve,
contrasting it with the beauty of a perfect circle.[181]

[178] _Purg._ xix. 1, 2.

[179] _Inf._ xx. 127-129.

[180] _Purg._ ix. 1-9.

[181] _Conv._ IV. xvi. 89-93.

[Illustration: Fig. 39. Sun, moon, and zenith.

To illustrate _Par._ xxix. 1-6. (_See p. 265_).

In the first figure the sun and moon are balanced, as it were, being at
equal distances from the zenith: in the second, a few minutes later,
by the rising of the sun and the setting of the moon, the balance is
disturbed, and each changes its hemisphere.]

Hardly ever does he find a beautiful epithet for her: she is ruler of
Hell,[182] Cain and the Thorns[183] (in reference to the legend which
sees this figure in her dark markings); or she is simply Delia,[184]
Trivia,[185] the daughter of Latona,[186] or with a little warmth
the sister of the sun,[187] and with the sun one of the two Eyes of
Heaven.[188] One exception to this harsh treatment is in the beautiful
description of reaching the heaven of the moon,[189] for there she is
the first star, the eternal pearl; and the sudden burst of eloquence in
the midst of a grave argument in _De Monarchia_ startles us doubly when
we find that Justice is compared to the moon—not, as one might expect,
resplendent in a dark sky, but Phœbe gazing at her brother opposite,
in the purple of the morning calm.[190] The passage from _Par._ xxix.
quoted above helps us to understand why the moon in this position
should symbolize Justice, for here again is suggested the perfect
balancing of the two great orbs, as the sun rises and the full moon
sets.

[182] _Inf._ x. 80.

[183] _Inf._ xx. 126.

[184] _Purg._ xxix. 78; _Ep._ vi. 54.

[185] _Par._ xxiii. 26.

[186] _Par._ x. 67; xxii. 139; xxix. 1.

[187] _Purg._ xxiii. 120.

[188] _Purg._ xx. 132.

[189] _Par._ ii. 25-36.

[190] _De Mon._ I. xi. 35-37.

Add to these passages two similes drawn not indeed from the moon
itself but from the halo surrounding her,[191] and two descriptions
of brilliant moonlight nights,[192] and we have all that Dante has
written in praise of the moon. It is true that throughout the _Inferno_
and _Purgatorio_ the sun typifies Divine Grace, and the moon is his
opposite, but this cannot altogether explain the difference in their
treatment, even in the _Divine Comedy_. A deeper reason seems to be
Dante’s true southerner’s love of the sun; and he doubtless had the
astronomer’s feeling that moonlight always means loss of starlight,
which he dearly loved (see _Purg._ xviii. 76, 77). Perhaps too the
astrological views of the moon influenced him, consciously or not.
According to Ristoro, the moon represents the poorest and lowest
classes of people, who are servants and messengers to the rest; and as
all the planets were supposed to be either masculine or feminine, he
ungallantly adds—“E questa Luna, a cagione di sua viltà, potemo dire
per ragione ch’ella sia femmina.”[193] Her only house, too, which is
Cancer, is also poor and base. The moon, moreover, is nearer Earth than
any other planet, and shows by her dark markings that she is less pure
than the rest.

[191] _Par._ x. 67-69; and _Purg._ xxix. 78.

[192] _Purg._ xxix. 53, 54; and _Par._ xxiii. 26.

[193] “And this moon, because of her inferiority, is rightly called
feminine.”

2. MOVEMENTS OF THE SUN.

Whatever the reason, Dante’s fifty-one references to the moon are in
strong contrast to his allusions to the sun. These are four times as
many, and they include warm expressions of admiration and delight,
and beautiful epithets and similes. The sun is Titan with his chariot
and horses,[194] he is a Mirror, a Car of Light, the Lantern of the
World, the Prince of the Stars, the Father of all mortal life.[195] His
beautiful form is admired, “la perfetta sua bella figura,”[196] and his
intense brilliance often noted.[197] He is the guide that leads all
aright,[198] to whom Virgil appeals:—

[194] _Ecl._ ii. 1-4.

[195] _Purg._ iv. 62, 63; _Purg._ iv. 59; and xxix. 117, 118; _Par._ i.
38; _Canz._ xix. 114; _Par._ xxii. 116.

[196] “The perfection and beauty of his shape.” _Canz._ xix. 76.

[197] _V. N._ xlii. 29; _Canz._ ix. 2; _Conv._ II. xiv. 126, 127;
_Purg._ xvii. 52, 53; _Par._ i. 54; and x. 48, etc.

[198] _Inf._ i. 17, 18.

    “O dolce Lume, a cui fidanza i’ entro
    Per lo nuovo cammin, tu ne conduci.”[199]

[199]
    “O pleasant light, my confidence and hope!
    Conduct us thou,” he cried, “on this new way.”
                              _Purg._ xiii. 16, 17. (_Carey_).

Under his rays the rose expands, the air is gladdened, mists are
dispelled, snow melts, and all things are quickened into life.[200]
Unlike the moon, the sun is the bringer of warmth and comfort, chasing
away cold and darkness,[201] sunrise is the hour of renewed hope and
confidence,[202] it strengthens our limbs, paralysed by the cold of
night,[203] it is eagerly awaited through the darkness by the little
bird on her nest;[204] and delicate flowers, bowed and closed during
the cold night, rise upright on their stems and open as soon as the sun
shines once more upon them.[205] The exquisite sunsets and sunrises of
the _Purgatorio_ are favourite passages with all readers.

[200] _Par._ xxii. 55, 56; _Inf._ vii. 122; _De Mon._ II. i. 37-39; and
_Par._ ii. 106-108; _Canz._ xi. 37; _Conv._ III. xii. 59, 60, etc. etc.

[201] _Canz._ ix. 5.

[202] _Inf._ i. 41-43.

[203] _Purg._ xix. 10, 11.

[204] _Par._ xxiii. 1-9.

[205] _Inf._ ii. 127-129.

Love is compared with the summer sun,[206] the generosity of a noble
nature resembles “the great planet.”[207] The Emperor Henry VII., from
whom Dante expected the regeneration of Italy and the whole Christian
world, is likened to the rising sun;[208] the birth of St. Francis is
described as “nacque al mondo un sole,”[209] and his birthplace ought
rightly to be called not Assisi but Orient.[210] Virgil is addressed
as “O Sol che sani ogni vista turbata;”[211] Beatrice is “Il sol degli
occhi miei.”[212] Finally the sun is the best symbol of God,[213]
and so it is used many times in the _Divine Comedy_: “Il Sol degli
angeli,”[214] “Il Sol che raggia tutto nostro stuolo;”[215] a spirit
turns to “il Sol che la riempie,”[216] and when Virgil laments that he
is shut out of heaven it is in these words: “Ho i’ perduto Di veder l’
alto Sol che tu disiri.”[217]

[206] _De Mon._ II. i. 36-41.; _Canz._ ix.

[207] _Canz._ xix. 96-114.

[208] _Ep._ v. 10; and vii. 19, 20, 25.

[209] “A sun rose upon the world.” _Par._ xi. 50.

[210] _Par._ xi. 52-54.

[211] “O sun that healest all imperfect vision,” _Inf._ xi. 91.

[212] “The sun of my eyes.” _Par._ xxx. 75 (See also _Par._ iii. 1-3).

[213] _Conv._ III. xii. 52-63.

[214] “The Sun of the angels.” _Par._ x. 53.

[215] “That Sun which enlightens all our company.” _Par._ xxv. 54.

[216] “The Sun which satisfies it.” _Par._ ix. 8.

[217] “I have lost the sight of that high Sun whom thou desirest.”
_Purg._ vii. 25, 26. Compare _Par._ xxx. 126; xv. 76; xviii. 105.

But we may not dwell on those thoughts of the sun as the typical giver
of light and life; we must ask what Dante says about his movements,
since this was the chief subject-matter of mediæval astronomy.

His daily course, “il cammin del Sole,”[218] is often spoken of, and
is indicated both by his position in the sky, and the length and
direction of shadows. The second _Eclogue_ begins with a description of
a breathlessly hot midday, when objects, which are usually shorter than
their own shadows, now surpassed them in length.

[218] “The path of the sun.” _Purg._ xii. 74.

    “Resque refulgentes, solitae superarier umbris,
    Vincebant umbras.” _Ecl._ ii. 5, 6.

At this time the sun appears most brilliant, and seems to move most
slowly, since he is scarcely changing his position with regard to the
horizon.

    “E più corrusco, e con più lenti passi,
    Teneva il sole il cerchio di merigge.”[219]

[219] “Shining more brightly and with slower steps, the sun had gained
the circle of midday.” _Purg._ xxxiii. 103, 104.

The greatest number of references to the sun’s daily journey occur in
the _Purgatory_, and we shall quote them in a later chapter.

His yearly journey through the zodiac is also very often referred to.
When relating his first meeting with Beatrice, Dante names his age, not
by simply saying that he was nearly nine years old, but by counting the
number of the times that the “heaven of light,” that is, of the sun,
had returned to the same point since his birth:—

    “Nove fiate già, appresso al mio nascimento, era
    tornato lo cielo della luce quasi ad un medesimo
    punto, quanto alla sua proprio girazione.”[220]

[220] “Nine times already since my birth had the heaven of light
returned to the selfsame point almost, as concerns its own revolution.”

    _V. N._ ii. 1-4. (_Rossetti_).

The sun’s “own revolution” is of course its apparent yearly movement,
as distinct from the diurnal movement which it shares with all the
heavenly bodies.

The same thought is expressed in a sonnet:

    “Io sono stato con Amore insieme
    Dalla circolazion del Sol mia nona.”[221]

We know further that Dante was born in either May or June, because he
says, when he finds himself among the stars of Gemini, that the sun was
rising and setting in this sign at the time of his birth.[222]

[221] “I have dwelt with Love since my ninth revolution of the sun.”
_Son._ xxxvi. 1, 2.

[222] See diagram on p. 276.

    “O gloriose stelle
    Con voi nasceva e s’ascondeva vosco
    Quegli ch’è padre d’ogni mortal vita,
    Quand’ io senti’ da prima l’ aer tosco.”[223]

[223]

    “O glorious stars ...
    With you was born, and hid himself with you,
    He who is father of all mortal life,
    When first I tasted of the Tuscan air.”
                        _Par._ xxii. 112-117. (_Longfellow_).

At this date the sun entered the _constellation_ of Gemini on June
1 (Old Style), but was in the _sign_ from May 11 to June 11, and it
is always to the signs that Dante refers in the _Divine Comedy_. The
anonymous fourteenth century commentator known as “l’Ottimo” interprets
this passage as indicating the time “between the middle of May and the
middle of June.”

Boccaccio tells us that a Mayday feast, given by the father of
Beatrice, was the occasion of Dante’s first meeting with her, and also
that not long before his death in Ravenna he told a friend that he had
completed his fifty-sixth year in the preceding May, so we may conclude
that May was the month of his birth.

Dante seems to have taken some trouble to find out the exact period of
the sun’s revolution. His text-book, the _Elementa_ of Alfraganus, only
gives it as 365¼ days nearly:—“Sol ... orbem confecit diebus 365 et
propè ¼.” Ristoro d’Arezzo and Brunetto Latini were content to repeat
this rough estimate, and call the year 365 days 6 hours, but Dante
wished to be more exact, and somehow contrived to obtain a value which
was much nearer the modern estimate of 365 days, 5 hours, 48 minutes,
46 seconds. We know this from two passages. In the _Convivio_ he gives
the half period as less than 182 days 15 hours; and in the _Paradiso_
Beatrice says that January will in time cease to be a winter month,
because of a neglected fraction of time.

    “Prima che gennaio tutto si sverni
    Per la centesma ch’ è laggiù negletta.”[224]

[224]
    “Ere January be unwintered wholly
    By the centesimal on Earth neglected.”
                     _Par._ xxvii. 142-143. (_Longfellow_).

January was in fact receding from the winter, and steadily though
slowly advancing towards the spring, because the Julian year (as we
saw, p. 171) was 11 minutes 14 seconds longer than the true solar
tropical year. When Julius Cæsar reformed the Calendar, March 25 was
made (as of old) to coincide with the spring equinox, but by Dante’s
time this date was 13 days late, and the true equinox fell on March 12.
Consequently though the day called January 1 still came 84 days before
March 25, it was only 71 days before the spring equinox.

If Beatrice meant to speak with scientific precision, and was correct
in her hundredth part of a day per annum, that is, if the difference
between the astronomical and the Julian year was one day in a hundred
years, it would be 7100 years before the first of January came to
coincide with the spring equinox, and January became a spring month.
But the error quoted is really rather too large, for a hundredth part
of a day is 14 minutes 24 seconds, and it was in fact only 11 minutes
14 seconds.

It would be interesting to know where Dante found this value, which
is practically the only astronomical datum not given in Alfraganus.
Ptolemy, following Hipparchus, had given the tropical year as ¹/₃₀₀
part of a day less than 365¼; Albategnius gave a more accurate figure,
and one which agrees well with the “centesma,” for his tropical year
differs from the Julian by a little less than ¹/₁₀₆ of a day; but he
also improved the value of precession, and Dante does not seem to have
known this, so he was probably not acquainted with this astronomer’s
work. The Alfonsine Tables gave a value which was very close indeed to
the correct one, making the tropical year only 30 seconds longer than
the modern value, and the difference between the Julian and true year
¹/₁₃₄ of a day. (The correct value is ¹/₁₂₈). Either of these figures
may have been known to Dante indirectly: perhaps he had obtained the
Alfonsine value in conversation with Brunetto Latini, who had visited
Alfonso’s court. His fraction was evidently only approximate, but it is
interesting to know that he had found out more than popular books could
tell him about the period of the sun’s revolution, and that he had been
sufficiently struck by the small difference between the calendar and
astronomical years to mention it in a picturesque way in his poem. It
is possible that he had heard of Roger Bacon’s appeal to the Pope in
1267 to correct the calendar because the date of the spring equinox was
of importance in connection with the observation of Easter.

It is hardly necessary to remind my readers that this was done by
another Pope three hundred years later, before January had made much
more advance towards becoming a spring month. The hundredth part of a
day, of which Beatrice complained, is now subtracted from the year by
omitting to make century years leap years; but as the error was really
not quite so great as she said, an exception is made for century years
divisible by 400. Thus 1600 was a leap year, but not 1700, 1800, or
1900.

[Illustration: Fig. 40. The Zodiac and the Months.]

Dante seems to have connected any season of the year with the sun’s
path in the zodiac as readily as with the name of a month. The sun’s
yearly course through the signs is shown diagrammatically in figure 40,
and a glance at this will make clear a number of allusions without any
explanation.

Starting from the first point of Aries at the spring equinox, which in
Dante’s time fell in the middle of March, and taking one-twelfth of
the year to traverse each sign, it is evident that during the end of
March and beginning of April the sun was in Aries; he entered Cancer
and reached the summer solstice in June, the autumnal equinox in Libra
in September, and the winter solstice when he entered Capricornus in
December. The six signs above the horizontal line are northern, the six
below are southern.

The following are a few typical examples.

When Dante wishes to express the transition of his feelings from
despondency to courage, at seeing the stern and troubled face of his
guide melt suddenly to a smile, he compares himself to a poor shepherd
who wakes early and sees the fields covered, as he thinks, with snow,
but in a short time finds that it is only hoar-frost which has put on
the semblance of her white sister, and seeing the face of the world
changed he gladly leads out his sheep to pasture. The time at which
this may happen is

    “Quella parte del giovinetto anno,
    Che il sole i crin sotto l’Aquario tempra,
    E già le notti al mezzodì sen vanno.”[225]

[225]
    “In that part of the youthful year wherein
    The sun his locks beneath Aquarius tempers,
    And now the nights draw near to half the day.”
                         _Inf._ xxiv. 1-3. (_Longfellow_).

That part of the youthful year when the sun cools his locks beneath
Aquarius is clearly the end of January or beginning of February, but
the last line may bear one of two meanings. If we translate “mezzodì”
as “half the day” it means that the nights are growing shorter, and
very soon (in March) when the sun will have reached the equinox, they
will be just twelve hours long. If we take “mezzodì” as meaning “the
south,” we must interpret the passage in the light of others in the
_Divine Comedy_ where Night is personified, and considered as circling
in the zodiac always opposite to the sun. For instance in _Purg._ ii.
1-6 (a passage which will be more fully explained later) Night is
described as circling opposite to the sun, “La notte, che opposita a
lui cerchia,”[226] and as the sun at that time was in Aries, Night was
in Libra, “le Bilance.” Henceforth for six months the sun will be in
the northern signs, and the days longer than the nights, but as soon as
Night begins to assert her supremacy, and the nights begin to be longer
than the days, the sun enters Libra and then it is not visible all
night. This is the meaning of

[226] “Night that opposite to him revolves.” (_Longfellow_).

                                “le Bilance,
    Che le caggion di man quando soverchia.”[227]

[227]
    “The Scales, that from her hands are dropped
    When she reigns highest.”
                              _Purg._ ii. 5, 6. (_Carey_).

When Night becomes dominant, the Scales fall from her hand, for the sun
is in that sign.

Applying this idea to the passage quoted above, it will mean “The
nights are going southward,” for the sun in Aquarius is not far from
the point where he crosses the equator to the north, therefore Night
circling opposite to him is nearing the point where she goes south.
Either interpretation is faithful to fact, but perhaps the circumstance
that the plural noun is used favours the first.

[Illustration: Fig. 41. The Ram on the Ecliptic. [_To face p. 279._

_From the “Cosmi Historia” of Robert Flud, a.d. 1612._

(_Reproduced from Brown’s Phainomena of Aratos._)]

Conrad Malaspina prophesied to Dante that his favourable opinion of the
Malaspina family would be justified “before the sun had come to rest
again seven times in the bed which the Ram covers and bestrides with
his four feet.”

    “Ed egli: Or va, che il Sol non si ricorca
    Sette volte nel letto che il Montone
    Con tutti e quattro i pie copre ed inforca
    Che cotesta cortese opinione ...”[228]

[228]
    “And he: Now go, for the sun shall not lie
    Seven times upon the pillow which the Ram
    With all his four feet covers and bestrides.
    Before that such a courteous opinion ...”
                    _Purg._ viii. 133-136. (_Longfellow_).

The sun was at the time in the Ram, and Malaspina means that less
than seven years would elapse, before his prophecy was fulfilled.
The aptness of the description may be seen by the figure of Aries
as portrayed in an old seventeenth century book in which the Ram is
uncomfortably trying to sit on the ecliptic.

Another instance is in the beautiful midwinter Ode, “Io son venuto al
punto della rota.”[229] Each stanza pictures a feature of a severe
winter—snow and rain, the absence of summer birds, bare trees and dead
flowers, the favourite walk become a torrent; but the first describes
the position of stars and planets. When the sun sets, the Twins
appear on the eastern horizon, hence we know at once that the sun is
in Sagittarius and the time is November or December. To confirm his
melancholy, the poet adds that the Star of Love (Venus) is hidden from
us by the sun’s rays which now shine athwart her, and that the planet
which strengthens the cold (Saturn, the “frigida stella” of Virgil)
displays himself in that arc of the sky in which all the seven planets
cast the shortest shadow;[230] that is, either he is on the meridian at
sunset, or he is in the most northerly part of the zodiac, in Gemini or
Cancer. A planet in this place, as for instance the sun at midsummer,
is visible longer, describes a longer arc, and casts shorter shadows,
than in any other part of the zodiac. And as this is the part which
rises over the eastern horizon as the sun sets, Saturn would also rise
at that time and remain visible all night.

[229] “I have come to that part of the wheel.” _Canz._ xv.

[230] Like all mediæval writers, Dante includes the sun and moon among
the seven planets. The others do not cast perceptible shadows, except
Venus and Jupiter at their brightest.

The opening lines of the Ode run thus:—

    “Io son venuto al punto della rota,
    Che l’orizzonte, quando il Sol si corca,
    Ci parturisce il geminato cielo;
    E la stella d’amor ci sta rimota
    Per lo raggio lucente, che la ’nforca
    Sì di traverso, che le si fa velo;
    E quel pianeta che conforta il gelo
    Si mostra tutto a noi per lo grand’ arco,
    Nel qual ciascun de’ sette fa poca ombra.”[231]

[231]
    “I to that point in the great wheel have come,
    Wherein the horizon, when the sun doth set,
    Brings forth the twin-starred heaven to our sight;
    And Love’s fair star away from us doth roam,
    Through the bright rays obliquely on it met
    In such wise that they veil its tender light;
    That planet which makes keen the cold of night
    Shows himself to us in the circle great,
    Where each star of the seven casts little shade.”
                                   (_Plumptre_).

It is astonishing that Giuliani should so completely miss the point of
the “twinned sky,” that he substitutes “ingemmato” for “geminato,” and
reads—

                               “ ... la rota,
    Ch’ all orizzonte, quando il Sol si corca,
       Ci parturisce l’ingemmato cielo.”[232]

[232] “The Wheel which, when the sun sets, brings forth for us on the
horizon the jewelled sky.”

He understands the hour of evening to be meant, when the Wheel of
Day and Night brings a jewelled, _i.e._ starry sky on the horizon as
the sun sets. But it is not only on the horizon that stars appear at
sunset; and the mention of Gemini to indicate the time of year is
thoroughly characteristic of Dante. The Wheel is the revolving year
which has carried the sun into Sagittarius.

Angelitti remarks that the whole description was literally true for
December 1296, since Venus was then in conjunction with the sun, and
Saturn in Cancer;[233] and as this poem is a complaint of the hardness
of his lady, to whom the poet is nevertheless wholly devoted, it may
well have been written in that time when the lady Philosophy refused to
smile upon her lover.[234]

[233] _Sulla Data del Viaggio Dantesco_ p. 90, note.

[234] Comparing _Conv._ II. ii. 12, xiii. 49-52, and IV. i. 60-62, we
learn that in August 1293 (_vide infra_, p. 314), Dante first became
acquainted with the Lady Philosophy; that in the early part of 1296 he
was completely under her spell; and that some time afterwards she for a
while estranged herself from him.

Further on in the same poem the effects of the sun in spring, when he
is in the sign of Aries, are alluded to as “the virtue of Aries”:—

    “Passato hanno lor termine le fronde,
     Che trasse fuor la virtù d’Ariete,
     Per adornare il mondo, e morta è l’ erba.”[235]

[235]
    “Scattered and faded now is all the foliage
    Which had burst forth, beneath the power of Aries,
    To beautify the world, the grass is withered.”    _Canz._ xv. 40-42.

Contrast with this the passage in the _Paradiso_ where “nocturnal
Aries” is used as a synonym for autumn.

    “Questa primavera sempiterna
     Che notturno Ariete non dispoglia.”[236]

[236]
    “This everlasting spring
    Nocturnal Aries never can despoil.”
                                _Par._ xxviii. 116-117.

For although Aries may be seen during some part of the night in the
greater part of the year, it is most emphatically a noctural sign when
it rises as the sun sets, and remains above the horizon until he rises;
this happens when the sun is in the opposite sign of Libra, which he
enters at the autumnal equinox.

A rather curious passage in the _Paradiso_ is incomprehensible unless
we think of the sun’s path in the zodiac, and realize that Dante is
comparing the brightness of the spirit of St. John in an indirect way
with the brightness of the sun.

    “Poscia tra esse un lume si schiarì,
    Sì che, se il Cancro avesse un tal cristallo,
    L’inverno avrebbe un mese d’un sol dì.”[237]

[237]
    “Thereafterward a light among them brightened
    So, that if Cancer one such crystal had
    Winter would have a month of one sole day.”
                     _Par._ xxv. 100-102. (_Longfellow_).

If a light as dazzling as this spirit were to shine forth in Cancer,
there would be perpetual day for a whole month in winter. For when the
sun entered Capricornus, which he does in December, he would be exactly
opposite, so that as one light set the other would rise, and there
would be no darkness until the sun passed into another sign.

To many similar instances the diagram (p. 276) will be found to supply
a key, and some we shall have occasion to notice presently in another
connection.

3. THE STARS.

If our poet did not love moonlight, there is no doubt that starlight
was very dear to him. Never are stars spoken of as cold, or placed in
antithesis to the sun. Rather are they classed together, as in the
pathetic letter, written when he heard of the possibility that the
Florentines might receive him again if he would consent to return as a
disgraced but pardoned criminal. If this is the only path to Florence,
never will he re-enter the beloved city. “What then?” he cries. “Can he
not see the mirrors of the sun and of the stars, wherever he may be?
can he not meditate on precious truths under any sky?”[238]

[238] _Ep._ ix. 46-49.

He describes the Inferno as bereft of stars as well as of sun;[239]
he hopes to escape those dark abysses to see the beautiful stars
again,[240] and the terror of the sounds of weeping and crying is
heightened indescribably by the simple words:—“risonavan per l’aer
senza stelle.”[241] When he does at length come forth to see “le cose
belle che porta il ciel”[242] how eagerly he gazes, not only at Venus,
but at the new stars in the south! how his “greedy eyes”[243] seek
the same region as soon as dusk begins to fall! and how radiantly the
stars look down upon him on that last night on the rocky slopes of the
Mountain, near the summit![244]

[239] _Inf._ iii. 23.

[240] _Inf._ xvi. 82, 83.

[241] “Resounded through the air without a star.” _Inf._ iii. 23.

[242] “The fair things that heaven holds.” _Inf._ xxxiv. 137, 138.

[243] _Purg._ viii. 85.

[244] _Purg._ xxvii. 89, 90.

This is all allegorical, no doubt, but it is because of Dante’s
feeling for the real “belle stelle”[245] that he uses them as symbols
of truth and holiness, and concludes each Cantica of the _Divine
Comedy_ with their name:—

[245] “Beautiful stars,” _Inf._ xvi. 83.

    “E quindi uscimmo a riveder le stelle.”[246]
    “Puro e disposto a salire alle stelle.”[247]
    “L’Amor che move il sole e l’altre stelle.”[248]

[246] “Thence issuing we beheld again the stars.”

[247] “Pure and disposed to mount unto the stars.”

[248] “The Love that moves the sun and the other stars.”

Here “stelle” has the wider meaning of the French “astres,” for which
we have no equivalent in English except the clumsy “heavenly bodies;”
but most of Dante’s hundred references are to stars in the more special
sense, and often to particular stars or constellations. Over eighty
occur in the _Divine Comedy_.

Stars are jewels, torches, flames, immortal nymphs adorning every
region of the sky.[249] Heaven is made beautiful by their light, and
the joy of the angels is expressed in their shining, as mortal joy
shines forth in human eyes.[250] If the spirits in the fourth heaven
are described as glowing suns,[251] the “splendours” that descend upon
the golden ladder in the seventh, make Dante think that all the stars
in the sky are gathered together there.[252]

[249] _Purg._ ix. 4; _Purg._ viii. 89; _Purg._ i. 25; _Par._ xxiii. 26.

[250] _Par._ ii. 130, 142-144.

[251] _Par._ x. 76.

[252] _Par._ xxi. 28-33.

The eyes of Beatrice shone brighter than stars;[253] light comes as
from many stars in reading the sacred books;[254] faith gleams like a
star in the sky;[255] and truth appears in a mind cleared of falsehood
and error like the radiance of stars in a sky which has been wholly
swept of cloud and mist by a north wind.

[253] _Inf._ ii. 55.

[254] _Par._ xxv. 70. See also _Conv._ II. xvi. 4-12, where the
writings of Boëthius and Cicero, and all instructive books, are called
stars full of light.

[255] _Par._ xxiv. 147.

    “Come rimane splendido e sereno
        L’emisperio dell’ aer, quando soffia
        Borea da quella guancia ond’ è più leno,
    Perchè si purga e risolve la roffia
        Che pria turbava, sì che il ciel ne ride
        Con le bellezze d’ogni sua paroffia:
    Così fec’ io, poi che mi provvide
        La Donna mia del suo risponder chiaro,
        E come stella in cielo il ver si vide.”[256]

[256]
    “Even as remaineth splendid and serene
        The hemisphere of air, when Boreas
        Is blowing from that cheek where he is mildest,
    Because is purified and resolved the wrack
        That erst disturbed it, till the welkin laughs
        With all the beauties of its pageantry:
    Thus did I likewise, after that my Lady
        Had me provided with her clear response,
        And like a star in heaven the truth was seen.”
                       _Par._ xxviii. 79-87. (_Longfellow_).

Stars, as well as the sun, are used as symbols for the objects of
Dante’s deepest reverence; for the Blessed Virgin is called “la viva
stella,”[257] and the Final Vision in which the redeemed find their
ultimate bliss is a Trinal Light seen as a single star:—

[257] “The shining star.” _Par._ xxiii. 92.

    “O trina Luce, che in unica stella
          Scintillando a lor vista sì gli appaga,
          Guarda quaggiù alla nostra procella.”[258]

[258]
    “O Trinal Light, that in a single star
        Sparkling upon their sight so satisfies them,
        Look down upon our tempest here below!”
                        _Par._ xxxi. 28-30. (_Longfellow_).

The diurnal motion of the stars is referred to many times. As Dante
watched the mystical procession in the Earthly Paradise, and saw one
group follow in the footsteps of another across the flowers and the
grass, he thought of the stately procession of stars which we see here
by night, star following star across the sky.[259] Their movement marks
for him the passage of time, as we see in the first sonnet of the _Vita
Nuova_:—

[259] _Purg._ xxix. 91.

    “Già eran quasi ch’ atterzate l’ ore
    Del tempo che ogni stella è piu lucente.”[260]

[260]
    “Of those long hours wherein the stars above
      Wake and keep watch, the third was almost nought.”
                        _V. N._ iii. 81, 82. (_Rossetti_).

and in the _Inferno_, where Virgil hastens Dante, saying that all
the stars are sinking which were rising when he started on his long
journey.[261]

[261] _Inf._ vii. 98, 99.

The motion of those stars which neither rise nor set, but are always
seen circling round the pole, is clearly described. In the heaven
of the sun, spirits gather round Dante and Beatrice, and circle
round them, “Come stelle vicine ai fermi poli;”[262] and the motion
of the stars near the pole is said to be slow, like the part of a
wheel which is near the axle.[263] We may compare these descriptions
with the statement of Alfraganus:—“Eæ stellæ (_i.e._ the northern
circumpolar) vertuntur omnes circa idem punctum. Et quei ex iis
puncto huic est vicinior, minorem conficit circulum: motusque ejus
appâret lentior.”[264] Dante assumes that his readers understand this
motion when he describes himself as seeing unknown stars near the
South Pole. The Mount of Purgatory is supposed to be situated in the
southern hemisphere, and at his first arrival, before dawn, he turns
to the right, after looking at Venus in the east, therefore to the
south, and sees near the pole four stars so brilliant that the whole
sky seems to rejoice in their radiance, and he pities the “widowed”
northern hemisphere because they are invisible there.[265] In the
evening, as soon as it begins to grow dark, although he is engaged
in an interesting discourse with a friend with whom he had exchanged
warm greetings, he looks eagerly once more towards the pole (note the
intensity expressed by the repeated “pure”)—

[262]

    “Like unto stars neighbouring the stedfast poles.”
                                      _Par._ x. 78.

[263] _Purg._ viii, 86, 87.

[264] “These stars all revolve round the same point, and the nearer a
star is to this point, the smaller is the circle that it makes, and the
slower its motion appears.” _El. Ast._ cap. ii.

[265] _Purg._ i. 22-27.

    “Gli occhi miei ghiotti andavan pure al cielo,
        Pur là dove le stelle son più tarde,
        Sì come rota più presso allo stelo.”[266]

[266]
                          “My insatiate eyes
    Meanwhile to heaven had travelled, even there
    Where the bright stars are slowest, as a wheel
    Nearest the axle.”
                     _Purg._ viii. 85-87. (_Carey_).

He now sees three bright stars which make this pole glow with light,
and Virgil says that the stars he saw in the morning are low, while
those now visible have risen higher to take their place.

    “Ed egli a me: Le quattro chiare stelle
        Che vedevi staman son di là basse,
        E queste son salite ov’ eran quelle.”[267]

[267]
    “And he to me: The four resplendent stars
        Thou sawest this morning are down yonder low,
        And these have mounted up to where those were.”
                       _Purg._ viii. 91-93. (_Longfellow_).

The diurnal movement of the starry heaven is also alluded to in the
_Convivio_, and contrasted with that immensely slow movement which was
discovered by Hipparchus, and is called by us Precession. The starry
heaven, says Dante, displays one of its poles to us, and keeps the
other hidden; and in like manner it displays only one movement to us,
and keeps the other almost hidden. By the first, it revolves once in
every day from east to west; the other is nearly insensible, being only
one degree in a hundred years, and it is from west to east.[268] This
is the value of precession as given by Alfraganus, following Ptolemy.

[268] _Conv._ II. xv. 10-14, and 96-104.

It was this stupendous and mysterious cycle which was used by Dante
to measure the age of Beatrice, though for his own he used (as we
saw) the ordinary measure of the sun’s period. When he first saw “la
gloriosa donna”[269] she had only been in this life so long that the
starry heaven had moved towards the east one-twelfth part of a degree.
Therefore, she was one-twelfth of a hundred years old, or 8 years 4
months, “so that it was near the beginning of her ninth year that she
appeared to me, and I saw her nearly at the end of my ninth.”[270]

[269] “The glorious Lady.”

[270] _V. N._ ii. 9-15.

Dante tells us how many stars had been counted by “the sages of Egypt,”
by whom he means Ptolemy and the other Alexandrians: he did not know
that the star catalogue of the _Almagest_ was originally made by
Hipparchus of Rhodes.

    “Dico ch’ il cielo stellato ci mostra molto stelle;
    chè, secondochè li savi d’Egitto hanno veduto,
    infino all’ultima stella che appare loro in
    meridie, mille ventidue corpora di stelle pongono,
    di cui io parlo.”[271]

[271]
    “I say that the starry heaven displays a multitude
    of stars to us, for as the Sages of Egypt have
    perceived, including the last star which appears
    to them in the south, they reckon one thousand
    and twenty-two starry bodies, of which I am now
    speaking.”
          _Conv._ II. xv. 18-22. (_Jackson_).

It will be noted that he carefully avoids saying that this is the
number of all the stars visible from the whole earth. Had he, like
Ristoro, run away with the idea that a blank space on the globe meant
a blank in the sky, his night sky seen from Purgatory would have been
strangely bare and dull! Yet both writers used the same text-book.
Dante is here following Alfraganus closely, for he had written in his
nineteenth chapter:—

    “Sciendum itaque sapientes inivisse mensuram
    stellarum fixarum omnium, quoad instrumentis
    observari eæ potuerunt, extremam usque meridiei
    partem, in tertio climate ipsis conspicuam....
    Stellæ universae quarum agi mensura potuit sunt
    mille viginti duæ.”[272]

[272] “You are to know that the Sages measured the places of all the
fixed stars as accurately as possible with their instruments, as far
south as they could see in the third climate.... The number of all the
stars which he was able to measure is one thousand and twenty-two.”

Both in the _Quæstio_ and the _Paradiso_ Dante notes how stars differ,
not only in their brightness or “magnitude,” but also in the quality of
their light, by which he probably means their colour:—

    “Videmus in eo [_sc._ cœlum stellatum] differentiam
    in magnitudine stellarum et in luce.”[273]

[273] “We see in it (the starry heaven) a difference in the magnitude
of the stars and in their light.” _Qu._ xxi. 19-21.

    “Lumi, li quali nel quale e nel quanto
     Notar si posson di diversi volti.”[274]

[274]
    “Lights many the eighth sphere displays to you
    Which in their quality and quantity
    May noted be of aspects different.”
                         _Par._ ii. 65-66. (_Longfellow_).

It seems as if it were the beauty and the movement of the starry sky
as a whole which appealed to Dante, rather than the distinguishing of
special stars and constellations. Those which he mentions are almost
all either in the zodiac, and used to denote the hour, the season, or
the position of one of the seven planets; or else they are near one of
the poles and illustrate the circumpolar motion.

All the zodiacal constellations are mentioned except Virgo and
Sagittarius. Besides the ordinary names of “Ariete,” “Libra,” etc.,
Aries is called “il Montone;”[275] Gemini “il segno che segue il
Tauro,” “gli eterni Gemelli,” and “il bel nido di Leda,”[276] in
reference to the mother of Castor and Pollux, its two brightest
stars; Libra is “le Bilance”;[277] Scorpio “il freddo animale”;[278]
Capricornus is “il Capra del ciel”;[279] and Pisces “la celeste
Lasca.”[280]

[275] “The Ram.” _Purg._ viii. 134; _Par._ xxix. 2.

[276] “The sign which follows Taurus,” _Par._ xxii. 110, 111; “The
eternal Twins,” xxii. 152; “The fair nest of Leda,” xxvii. 98.

[277] “The Balance.” _Purg._ ii. 5.

[278] “The cold creature.” _Purg._ ix. 5.

[279] “The Goat of the sky.” _Par._ xxvii. 69.

[280] “The celestial Carp.” _Purg._ xxxii. 54.

In one place Castor and Pollux are mentioned, but merely as a synonym
for the whole constellation of Gemini.[281] “Il petto del Leone
ardente”[282] is perhaps Cor Leonis, the Heart of the Lion, for this is
the name given to Regulus by both Ptolemy and Alfraganus. The “Maggior
Fortuna”[283] of _Purg._ xix. 4, is a group of stars belonging to the
two constellations of Aquarius and Pisces, in which the geomancers, who
told fortunes by means of certain points traced at random, thought they
saw a special series of these points,-:::..

[281] _Purg._ iv. 61.

[282] “The burning Lion’s breast.” _Par._ xxi. 14.

[283] “Greater Fortune.”

It is generally agreed that the “gemme” of _Purg._ ix. 4, “poste in
figura del freddo animale, Che con la coda percote la gente,”[284] are
some stars of Scorpio which were shining on the eastern horizon just
before the moon rose on the first night in the Island of Purgatory.

[284]
    “Gems ... set in the shape of that cold animal
       Which with its tail doth smite amain the nations.”
                                              (_Longfellow_).

The zodiacal constellations in general are spoken of as “all the
lights of his [the sun’s] path:” “Tutti i lumi della sua strada.”
(_Par._ xxvi. 121, 122).

The pole star is described as the point of the axle round which the
first sphere revolves.[285] The first sphere (or wheel, as it is
called, with reference to its circling motion) is here the Primum
Mobile, which was thought to cause the diurnal motion. This unique
position gains for the pole star the name of “the star,” as for
instance in _Conv._ III. v. 84, 85, where Dante says that a man
standing at the north pole would have “la stella” directly over his
head. And in Paradise he hears a voice among the spirits which makes
him turn in its direction as the needle turns to the star—

[285] _Par._ xiii. 11, 12.

              “Voce, che l’ago alla stella
    Parer mi fece in volgermi al suo dove.”[286]

[286]
                                “A voice,
    That made me seem like needle to the star,
    In turning to its whereabout.”
                     _Par._ xii. 29, 30.  (_Carey_).

This property of the magnet was known in Dante’s day, as well as its
power of attracting iron, though only the latter had been known to
Ptolemy and the classical world. Whether the discovery came from China,
where it is said that some form of compass has been used since the
second century A.D., or whether it had been discovered independently
by Arab or Italian navigators, we do not know: but scholars and poets
in the twelfth and early thirteenth centuries write of the “ugly brown
stone” used by sailors to make an instrument that cannot lie. For a
needle, rubbed by it and run through a straw, when floated on water
turns so surely to “the star” that one need never doubt its guidance.
Thus writes Guyot, the poet of Languedoc, about 1200:—

    “Un art font qui mentir ne puet,
    Par la vertu de la manete,
    Une pierre laide et brunete,
    Ou le fers volentiers se joint,
    Ont: si esgardent le droit point,
    Puis c’une aiguile i ont touchie,
    Et en un festu l’ont couchie,
    En l’eve la metent sanz plus,

    Puis se torne la pointe toute
    Contre l’estoile si sanz doute,
    Que ja nas hom n’en doutera.”

And thus Ristoro:—

    “L’angola, che guidi li marinari, chè per la virtu
    del cielo è tratta e rivolta alla stella la quale è
    chiamata tramontana.”[287]

[287] “The needle which guides mariners, for by the virtue of the
heavens it is attracted and turned towards that star which is called
the North Star.” _Composizione del Mondo_, Bk. VII. part iv. ch. 2.

Albertus Magnus speaks of it in the same way, as something well known
to mariners.

It seems strange to us how Dante and his contemporaries failed to see
the importance of this discovery; Brunetto Latini, when the ugly stone
was shown to him on his visit to Roger Bacon at Oxford, even professing
to regard it as a mere toy, of no practical use. Dante discusses the
number of the stars known to Ptolemy, and describes the last mad voyage
of Ulysses, who saw all the stars of the other pole, while ours sank
low on the ocean floor;[288] but he does not seem to guess that the new
toy would make possible even longer voyages than these, and that in
time the blank in his celestial globe would be filled.

[288] _Inf._ xxvi. 127-129.

Yet even in his own life-time plucky little Genoa fitted out two
galleys which ventured through the forbidden Straits, with intent to
circumnavigate Africa and find a new route to India. And meanwhile,
travelling by old overland or coasting routes, Italian missionary
monks, and Italian traders, were visiting southern countries and
describing southern skies. Friar Giovanni de Monte Corvino, who was
in South India with Nicolo of Pistoia, writes home in 1291, telling
of his disappointment that he had never been able to see “the other
pole star” (l’altra tramontana), though he saw new stars moving round
and evidently near to it, close to the southern horizon. A few years
later Marco Polo the Venetian was dictating the story of his travels to
a Pisan in Genoa: he had been further south than the missionaries, for
in a certain island (probably Sumatra) he had seen the south pole “a
spear’s length” above the horizon; and in the land of Zinzi (Zanzibar?)
he had seen a marvellous star as big as a sack (which was evidently the
Greater Magellanic Cloud). This he drew a picture of with his own hand.

Dante’s silence, and probable incredulity, regarding these experiences
of his own countrymen and contemporaries is characteristic of his
age; for scholars were too eager to explore the precious classical
lore lately recovered from oblivion, to realize that they were on the
threshold of a new era in knowledge, of which these men were pioneers.

It is sometimes thought, however, that Dante made use of contemporary
observations of southern skies in his description of the stars he
feigned himself to have seen when the Wain disappeared under his
northern horizon.[289] Quite correctly, he does not place any single
bright star to mark the south pole; his two constellations, one of four
bright stars seen above the pole in the morning,[290] one of three
which takes its place after sunset,[291] are these real or fictitious?

[289] _Purg._ i. 30.

[290] _Purg._ i. 26.

[291] _Purg._ viii. 89.

It is a fact that there are four bright stars in the form of a cross,
lying between 56° and 63° south: are these Dante’s “quattro chiare
stelle,” “quattro luci sante?”[292] They were not recognized as a
separate constellation until the beginning of the sixteenth century,
when Amerigo Vespucci described them in his letters about his southern
voyages, and the Florentine Andrea Corsali wrote about the marvellous
Cross which was so beautiful that in his opinion no other constellation
in the sky was worthy to be compared with it. This, he believed, was
the very cross of which Dante had spoken in a prophecy.

[292] “Four bright stars, four sacred lights.”

Even among Dante’s most enthusiastic admirers, I suppose none will be
found to-day to support this view; but many think that he must have
heard of the Cross from travellers. True, these stars are visible
during at least part of the year in all places south of 34° north, and
therefore in North Africa, and they had been catalogued by Ptolemy as
part of the Centaur, so that no astronomer could take them to be a
newly-found constellation, but might not some unscientific traveller
like Marco Polo have brought a vague report of their position?

[Illustration: MAP OF STARS VISIBLE BEFORE DAWN IN PURGATORY. _To face
p. 295_]

To this we might reply that Dante never says his four stars were in
the form of a Cross; that there had to be four to represent the four
Pagan virtues, the other constellation of three representing the three
Christian virtues (compare the group of four handmaidens who sing, “Noi
siam qui ninfe, e nel ciel siamo stelle,”[293] and are followed by a
group of three);[294] and that this other constellation was certainly
imaginary, since there is no group of three bright stars anywhere near
the south pole.

[293]
    “We are nymphs here, and in heaven we are stars.”
                                     _Purg._ xxxi. 104-106.

[294] _Purg._ xxxi. 111.

But the fact is that conjectures and arguments are unnecessary, since
Dante has expressly said that his four stars had never been seen before
by anyone except the first people—“non viste mai fuor che alla prima
gente,” (_Purg._ i. 24)—that is, our first parents, in that Eden of his
imagining which was in the southern hemisphere, and on the island where
he was then standing in his vision.

As a matter of curiosity I have included a map showing what stars
would have been really visible to Dante at the supposed latitude of
Purgatory, when Pisces was on the eastern horizon, as described in
_Purg._ i. It will be seen that the Southern Cross is low, and would
have been hidden behind the Mountain of Purgatory at five o’clock in
the morning.[295]

[295] Antonelli thinks the four stars were α and β Crucis, α and β
Centauri, all of which had been mentioned by Ptolemy, and all lie
near the circle which marks the limit of circumpolar stars in the
supposed latitude of Purgatory (32° south). The three stars he says
were ζ Navis, Canopus, and Achernar:—Antonelli, _Accenni alle Dottrine
Astronomiche nella Divina Commedia_.

Among northern constellations, Ursa Major is frequently spoken of by
Dante, under different names, but always with reference to its high
northern latitude. As the Wain, “il Carro,” it is said to be lying
in the north-west when Pisces is on the eastern horizon, and to have
disappeared from view in the southern hemisphere.[296] The wain-pole
or shaft is pictured as sweeping round in the diurnal revolution,
but always remaining above our horizon day and night, throughout its
turning:

[296] _Inf._ xi. 113, 114; _Purg._ i. 30.

                “Quel Carro, a cui il seno
    Basta del nostro cielo e notte e giorno,
    Sì ch’ al volger del temo non vien meno.”[297]

[297]
    “The Wain, that in the bosom of our sky
     Spins ever on its axle, night and day.”
                           _Par._ xiii. 7-9.  (_Carey_).

The same idea is expressed in the Midwinter Ode, where the
constellation is called the Seven Frosty Stars, never lost to sight in
Europe:—

    “Fuggito è ogni augel che ’l caldo segue
     Dal paese d’Europa, che non perde
     Le sette stelle gelide unquemai.”[298]

[298]
    “Fled is every bird that seeks the warmth,
    From European lands which never lose
    The seven cold stars.”
                          _Canz._ xv. 27-29.

This is a reminiscence of some lines of Boëthius quoted by Dante in
_De Monarchia_, in which the northern nations are described as under
the sway of the “septem gelidi triones.”[299] The Septem Triones, the
Seven Ploughing Oxen, was one of the Latin names for Ursa Major, whence
comes “septentrional” for North. This name also is used by Dante in
_Purg._ xxx. 1, where the Seven Candlesticks of the mystic procession
seen in the Garden of Eden are likened to these seven stars, and are
named the Septentrion of the First Heaven (the Empyrean). This divine
Septentrion was guiding the Procession, as the starry Septentrion of a
lower heaven guides the mariner into port:

[299]
    “Seven cold oxen.”
                _De Mon._ II. ix. 96.

              “faceva lì ciascuno accorto
    Di suo dover, come il più basso face
    Qual timon gira per venire a porto.”[300]

[300]
                        “To duty there
    Each one convoying, as that lower doth
    The steersman to his port.”
                        _Purg._ xxx. 4-6.  (_Carey_).

Like the seven stars, also, the heavenly Septentrion is said
figuratively to know neither setting nor rising, but unlike them it
knows no cloud except of sin.[301] Because it is spoken of as guiding
mariners, some commentators have taken the above to refer rather to
Septentrio Minor (Ursa Minor), which also has seven chief stars, and
is a better guide because nearer the Pole, as Thales taught; but the
comparatively faint stars of the Little Bear would not be so apt a
comparison with the celestial lights.

[301] _Purg._ xxx. 1-3.

By the name of the Bears, both Ursa Major and Minor are referred to as
guides at sea in _Par._ ii. 9. In the strange new seas on which Dante
warns his readers he is about to enter, Minerva will blow a favouring
wind, Apollo will steer the barque, and the nine Muses will guide his
course by the Bears. They are also spoken of together in _Purg._ iv.
65, to indicate the northern part of the sky.

A fifth name for Ursa Major is derived from the fable (known to Dante
probably from Ovid’s _Metamorphoses_) of the nymph Helice, who was
turned into a she-bear by Juno, and was hunted by her own son, Orcas.
Jupiter transformed them into Ursa Major and Boötes.

    “Se i barbari, venendo di tal plaga
       Che ciascun giorno d’Elice si copra,
       Rotante col suo figlio ond’ ell’ è vaga,
     Vedendo Rome e l’ ardua sua opra,
       Stupefaciensi....”[302]

[302]
    “If the barbarians coming from some region
      That every day by Helice is covered,
      Revolving with her son whom she delights in,
    Beholding Rome and all her noble works
      Were wonder-struck....”
                        _Par._ xxxi. 31-35. (_Longfellow_).

Here we have the same idea as of the Wain wheeling round but never
setting, with the addition of a neighbouring constellation describing a
circle in the same time.

The Barbarians who lived in a region always dominated by Ursa Major,
and came to marvel at the mighty buildings of ancient Rome, are
probably the races of northern Europe in general; and this reminds
us again of the lines of Boëthius quoted above, for it is among the
peoples ruled by Rome that he mentions “quos premunt septem gelidi
triones.”[303] If, however, Dante meant a country where the seven stars
pass exactly overhead, the barbarians must have inhabited Scotland, or
southern Scandinavia, or central Russia. If he means that Boötes also
remained always above the horizon, they must have come from within the
Arctic Circle, but this is not likely.

[303] “Those under the sway of the seven cold oxen.”

[Illustration: Fig. 42. Ursa Minor as a Horn. _Par._ xiii. 10.]

In one of the passages just quoted other constellations and stars are
mentioned together with Ursa Major. In _Par._ xii. Dante has compared
the two circles of spirits which surround Beatrice and himself to a
double rainbow, and to two garlands of immortal roses. In the next
canto he finds a new simile: in imagination he takes some of the
brightest and most familiar stars from our sky, and makes of them two
new constellations in the form of two crowns. The stars are these:
fifteen from different parts of the sky, which are so brilliant that
they shine through air dense enough to quench lesser orbs; the Wain,
which never sets in our sky; and the mouth of the horn whose tip is
the axis on which the Primum Mobile revolves. That is to say, as we
have before remarked, Dante takes the fifteen first-magnitude stars and
the stars instanced by Alfraganus as of second magnitude. Ursa Minor
is aptly compared to a horn, the wide mouth of which is formed by its
two bright stars Beta and Gamma,[304] while the narrow end is Alpha,
the Pole Star. These twenty-four bright stars we must then imagine to
group themselves into two constellations like that into which Ariadne,
the daughter of Minos, was changed when she died; this is Corona
Borealis or the Northern Crown, otherwise called Ariadne’s Crown,
which suggests a circle, though it is not a perfect one. Dante uses the
word “segni” for any constellations, a custom we find in Ristoro also,
although the modern usage is to restrict “signs” to mean only divisions
of the zodiac.

[304] I do not know whether this comparison originated with Dante, but
it was well known to Spanish sailors two centuries later. In the _Arte
of Navigation_ which was “Englished out of the Spanyshe,” by Richard
Eden in 1561, Beta and Gamma of Ursa Minor are referred to as “two
starres called the Guardians, or the mouth of the horne.”

The star-like spirits, thus grouped into a surpassingly brilliant
double constellation, begin to sing their ineffable heavenly song, and
to circle round the centre where Dante stands, in a marvellous dance,
whose swiftness, when compared with anything known on earth, is as the
movement of that swift heaven which carries with it all the rest, when
compared with the flowing of the sluggish river Chiana.[305]

[305] _Par._ xiii. 1-28.

This passage helps us to understand expressions which often strike
one as very strange, describing the circling movements of the spirits
in Paradise. For the likeness to stars is clear throughout. Their
brightness is an expression of their happiness,[306] and increases in
each succeeding heaven. Only in the lowest can Dante see the forms and
features of Piccarda and the other blessed spirits; in the next they
clothe themselves in light, and although at first the radiant eyes of
Justinian are seen, the first words addressed to him cause him to shine
more brilliantly than before, and as the sun conceals himself by his
own light, so the spirit conceals himself by the splendour which grows
with his joy.[307] In the third heaven the spirits shine in the star
of Venus like sparks seen in flame;[308] in the fourth they are called
suns, and surpass the sun in brilliancy;[309] in the fifth they are
compared with the Galaxy[310] and with shooting stars,[311] in the
seventh and eighth with stars[312] and with spheres of light, turning
on fixed poles and flaming like comets.[313]

[306] _Par._ viii. 52, 53.

[307] _Par._ v. 136, 137.

[308] _Par._ viii. 16.

[309] _Par._ x. 76, 40-42.

[310] _Par._ xiv. 97-101.

[311] _Par._ xv. 13, 14.

[312] _Par._ xxi. 32, 33; xxiii. 26, 27.

[313] _Par._ xxii 23; xxiv. 11, 12.

In like manner the swiftness of their motion increases in proportion
to the clearness with which each beholds eternal truth.[314] The
almost incredible speed with which Dante himself soars from sphere to
sphere, and with which the spirits move—whether in coming towards him,
impelled by Divine charity, in returning to the heaven of heavens,
or in circling with one another in mystic dance—is frequently dwelt
upon, and illustrated by many striking similes. The dance is always a
circling or wheeling movement (“il giro,” “la rota,” _Par._ viii. 20
and 26; ix. 65). And besides this, individual spirits turn with a rapid
motion, remaining on the same spot. Descending the celestial Ladder in
the heaven of Saturn, step by step, they revolve:—

[314] _Par._ viii. 20, 21; and xxviii. 100-102.

                  “Vid’ io più fiamelle
    Di grado in grado scendere e girarsi,
    Ed ogni giro le facea più belle.”[315]

[315]
                    “Saw I many little flames
    From step to step descending and revolving,
    And every revolution made them fairer.”
                     _Par._ xxi. 136-138.  (_Longfellow_).

Compare 80, 81 and 39; and _Par._ xxiv. 10, 11.

Now these two things, their light and their movements, were all the
facts concerning the stars which mediæval astronomers could observe;
and the movements were thought to be in circles and inconceivably
rapid. Motion in circles, and especially the movement of rotation
on an axis, remaining in the same place, had been said by Aristotle
to be the most noble form of motion, and the fittest for celestial
bodies. Therefore, when Dante represents the redeemed and the angels
as expressing their bliss by radiance and marvellously rapid motion
in circles, he makes them resemble the heavenly spheres and stars
among which they manifest themselves to him. The motions are directly
compared with those of stars in the passage already quoted:—

    “Poi, sì cantando, quegli ardenti soli
        Si fur girati intorno a noi tre volte,
        Come stelle vicine ai fermi poli.”[316]

[316]
    “As soon as singing thus those burning Suns
      Had round about us whirled themselves three times,
      Like unto stars neighbouring the steadfast poles.”
                         _Par._ x. 76-78.  (_Longfellow_).

Remembering this significance of circular motion we shall feel a little
less strange the similes of a mill and a top applied to the spirits of
Paradise.[317]

A third way in which the spirits express their joy is by the sweetness
of their song,[318] and here also they resemble the heavenly bodies,
which make sweet music as they circle. This doctrine of Pythagoras was
very popular throughout the Middle Ages.

[317] _Par._ xxi. 80, 81; xii. 3; xviii. 41, 42.

[318] _Par._ xxiv. 22-24, x. 73, and many others.

4. THE GALAXY.

The Galaxy or Milky Way is twice referred to in the _Divine Comedy_. In
_Inf._ xvii. 106-108, it is in connection with the myth of Phaeton, who
being allowed by his father Jove to drive the chariot of the sun for
one day, lost control of his chargers, and going all astray, burned the
sky in a part which still shows signs of this catastrophe, _i.e._ the
Milky Way.

    “Quando Fetòn abbandonò li freni,
     Per che il ciel, come pare ancor, si cosse.”[319]

[319]
    “What time abandoned Phaëton the reins,
     Whereby the heavens, as still appears, were scorched.”
                      _Inf._ xvii. 107-108.  (_Longfellow_).

This of course is only a poetical myth. But in the _Paradiso_, in three
lines the appearance, colour, and approximate position of the Galaxy
are described, and allusion is made to the difference of opinions
between learned men with regard to the puzzling question of its
nature. Dante is in the heaven of Mars. He sees the soldier saints,
star-like and fiery red, some larger and some less, thronging thick
in two great bands, which, crossing one another in the depths of the
planet, form a marvellous Crucifix. The crowded lights make him think
of the Galaxy, with its multitudinous points of light, differing in
brightness, although that is white, and lies in a great circle between
the celestial poles.

    “Come, distinta da minori e maggi
       Lumi, biancheggia tra i poli del mondo
       Galassia sì che fa dubbiar ben saggi,
     Sì costellati facean nel profondo
       Marte quei rai il venerabil segno
       Che fan giunture di quadranti in tondo.”[320]

[320]
    “Even as, distinct with less and greater lights,
       Glimmers between the two poles of the world
       The Galaxy that maketh wise men doubt,
     Thus constellated in the depths of Mars
       Those rays described the venerable sign
       That quadrants joining in a circle make.”
                     _Par._ xiv. 97-102.  (_Longfellow_).

If we now turn to the fifteenth chapter of Treatise II. of the
_Convivio_, we shall find the Phaeton myth and the various theories
about the Milky Way set forth in due order, and shall learn which of
these Dante considered to be true.

He is comparing the two sciences of Metaphysics and Physics with the
Heaven of the Fixed Stars, and takes the opportunity to tell us some
of the most important facts known about it. Here he calls the Galaxy
a circle:—“La Galassia, cioè quello bianco cerchio che il vulgo
chiama la Via de Santo Jacopo.”[321] This popular name perhaps arose
through a confusion of Galaxy and Galicia, where was a famous shrine
of St. James, and hence came the belief in Italy that the _Galassia_
was a sign by night to guide pilgrims on their way to this shrine at
Compostella in _Galizia_.

[321] “The Galaxy, that is, the white circle commonly called St.
James’s Way.”

Dante proceeds as follows with his comparison:—

    “E per la Galassia, ha questo cielo grande
    similitudine colla Metafisica. Perchè è da sapere
    che di quella Galassia li filosofi hanno avuto
    diverse opinioni. Chè li Pittagorici dissero che ’l
    sole alcuna fiata errò nella sua via, e, passando
    per altre parti non convenienti al suo fervore,
    arse il luogo, per lo quale passò; e rimasevi
    quell’ apparenza dell’ arsura. E credo che
    si mossero dalla favola di Fetonte, la quale
    narra Ovidio nel principio del secondo di
    _Metamorfoseos_. Altri dissero (siccome fu
    Anassagora e Democrito) che ciò era lume del sole
    ripercosso in quella parte. E queste opinioni
    con ragioni dimostrative riprovarono. Quello che
    Aristotile si dicesse di ciò, non si può bene
    sapere, perchè la sua sentenza non si trova cotale
    nell’ una traslazione come nell’ altra. E credo
    che fosse l’errore de’ traslatori; che nella
    Nuova par dicere che ciò sia uno raunamento di
    vapori sotto le stelle di quelle parte, che sempre
    traggono quelli; e questa non pare avere ragione
    vera. Nella Vecchia dice, che la Galassia non è
    altro che multitudine di stelle fisse in quella
    parte, tanto picciole che distinguere di quaggiù
    non le potemo, ma di loro apparisce quello albore
    il quale noi chiamiamo Galassia. [E puote essere
    che il cielo in quella parte è più spesso, e
    però ritiene e ripresenta quello lume] e questa
    opinione pare avere, con Aristotile, Avicenna e
    Tolommeo. Onde conciossiacosachè la Galassia sia
    uno effetto di quelle stelle le quali non potemo
    vedere, se non per lo effetto loro intendiamo
    quelle cose, e la Metafisica tratta delle prime
    sustanze, le quali noi non potemo simigliantemente
    intendere se non per li loro effetti; manifesto è
    che ’l cielo stellato ha grande similitudine colla
    Metafisica.”[322]

[322]
    “And in the Galaxy this heaven has a close
    resemblance to Metaphysics. Wherefore it must be
    known that the Philosophers have had different
    opinions about this Galaxy. For the Pythagoreans
    affirmed that the sun at one time wandered in its
    course, and in passing through other regions not
    suited to sustain its heat, set on fire the place
    through which it passed; and so these traces of the
    conflagration remain there. And I believe that they
    were influenced by the fable of Phaëton, which Ovid
    tells at the beginning of the second book of the
    _Metamorphoses_. Others (as for instance Anaxagoras
    and Democritus) said that the Galaxy was the light
    of the sun reflected in that region. And these
    opinions they confirmed by demonstrative reasons.
    What Aristotle may have said about it cannot be
    accurately known, because the two translations give
    different accounts of his opinion. And I think that
    any mistake may have been due to the translators,
    for in the _New Translation_ he is made to say
    that the Galaxy is a congregation, under the stars
    of this part of the heaven, of the vapours which
    are always being attracted by them; and this
    opinion does not appear to be right. In the _Old
    Translation_ he says that the Galaxy is nothing but
    a multitude of fixed stars in that region, stars
    so small that they are not separately visible from
    our earth, but the appearance of whiteness which
    we call the Galaxy is due to them. [And it may be
    that the heaven in that part is more dense, and
    therefore retains and reproduces that light] and
    this opinion Avicenna and Ptolemy appear to share
    with Aristotle. Therefore, since the Galaxy is an
    effect of those stars which cannot be perceived
    except so far as we apprehend these things by
    their effect, and since Metaphysics treats of
    primal substances which in the same way we cannot
    apprehend except by their effects, it is plain that
    there is a close resemblance between the starry
    heaven and Metaphysics.”
                    _Conv._ II. xv. 44-86.  (_Jackson_).

This characteristic passage is interesting for several reasons. It
illustrates the mediæval fondness for allegory, the reluctance to
believe that Aristotle could ever be wrong, and the interest in ancient
Greek speculations, in all of which Dante expresses the feelings of his
age: and it brings vividly before us the methods and the difficulties
of mediæval authors. For Dante is repeating from Albertus Magnus
all these ancient speculations: the officious copyist who altered
Aristotle’s words, the fact that Aristotle could only be read in
Latin, and the variety of translations, were all everyday obstacles
to study; and Dante’s own book has suffered from one of them in this
very passage. The words placed between brackets are evidently an
interpolation (as Mr. Wicksteed observes in the “Temple” _Convivio_):
without them the passage goes on smoothly and logically to its end.
On the assumption that the Galaxy is composed of a multitude of small
stars, but not that the sky is denser in that part, the parallel with
Metaphysics holds good.

Dante therefore held the true opinion about the Milky Way, but he was
mistaken in thinking that he had the support of Aristotle. It was the
“New Translation” (made by Aquinas from the Greek) which gave his
opinion correctly; in the “Old” (made by Michael Scot from the Arabic)
his statement had been apparently changed without comment into one
which seems to Dante—and also to us—to represent the truth about the
Galaxy.

5. THE PLANETS.

All the planets which were known before the days of the telescope are
mentioned by Dante several times. Each has its peculiar beauty, but “la
lucentissima stella di Venere”[323] is brighter and more beautiful than
any other. He speaks of “la chiarezza del suo aspetto, ch ’è soavissima
a vedere più che altra stella.”[324]

[323] “That most brilliant star, Venus.” _Conv._ II. iv. 88.

[324] “The brightness of her appearance, which is more lovely to behold
than that of any other star.” _Conv._ II. xiv. 112, 113.

No reader of the _Purgatorio_ can ever forget that matchless morning on
which Dante, escaping at last from the murky gloom of the _Inferno_,
sees the sky once more, pure blue even to its furthest limits, and the
planet of love shining in the east.

    “Dolce color d’oriental zaffiro,
       Che s’accoglieva nel sereno aspetto
       Dell’ aer, puro infino al primo giro,
     Agli occhi miei ricominciò diletto,
       Tosto ch’ i’ uscii fuor dell’ aura morta,
       Che m’avea contristati gli occhi e il petto,
     Lo bel pianeta che ad amar conforta
       Faceva rider tutto l’oriente,
       Velando i Pesci ch’erano in sua scorta.”[325]

[325]
    “Sweet colour of oriental sapphire,
      Which was gathering in the serene aspect
      Of the sky, pure even to the first circle,
    To my eyes restored delight,
      So soon as I had come forth from that dead air,
      Which had troubled eyes and breast.
    The fair planet that inspires love
      Was making all the orient smile,
      Veiling the Fishes which were in her train.”

Alternative rendering of the first three lines:—

    “Sweet colour of oriental sapphire,
      Which was diffused over the tranquil scene,
      From mid-heaven even to the first circle.”
                               _Purg._ i. 13-21.

Strange to say, the beginning of the above beautiful passage which
conveys so direct and vivid an impression of blue sky and pure air,
presents some difficulties when one comes to translate it word by
word, especially as the texts offer more than one reading. By some
commentators the “primo giro”[326] has been understood to mean the
sphere of the moon,[327] or even the highest sphere (the Primum
Mobile); but this is certainly inadmissible, as Dante supposed the
atmosphere to reach only as far as the sphere of Fire, which came
between it and the moon. The prime circle is here evidently the
horizon, the fundamental circle of observers, the First Circle of the
astrologers, from which they reckoned all the rest. It is here that the
sky usually becomes pale and misty, however blue and clear it may be
above. The colour was gathering and deepening,[328] especially in the
east, where Dante was looking, as dawn began to appear in a perfectly
cloudless sky; for during the darkness of the night it would have
appeared almost black.

[326] First, or prime, circle.

[327] _Conv._, II. iv. 1-3.

[328] Literally, “was assembling,” or “was being collected.”

Dr. Moore thinks the authority better for a different reading, viz.
“Dal mezzo”[329] instead of “Dell’ aer.”[330] In this case, we must
take “mezzo puro” to mean mid-heaven, that is the zenith, “puro” being
used as a noun, and meaning a cloudless sky (like “sereno” in _Purg._
v. 38); and “il sereno aspetto” must mean “the quiet scene.”

[329] “From the middle.”

[330] “Of the air.”

Venus appears again in the _Purgatorio_, shining upon the Mountain from
the east before sunrise; and this time she is called Cytherea, after
the island near which she was fabled to have risen from the sea, and in
which she received a special worship.

        “Dell’ oriente ... raggiò nel monte Citerea,
    Che di foco d’amor par sempre ardente.”[331]

[331] “From the east there shone upon the Mountain Cytherea, who in the
flame of love seems to be always burning.” _Purg._ xxvii. 94-96.

The position of Venus in her course through the zodiac is indicated
in the previous passage by the expression “velando i Pesci.”[332] The
oscillating motion, by which she appears first on the morning and then
on the evening side of the sun is referred to several times. In prose
Dante speaks of her two apparitions, the morning and the evening: “la
sua apparenza, or da mane, or da sera;”[333] in poetry, he describes
her as wooing the sun, first following and then facing him:—

[332] “Veiling the Fishes” (the zodiacal constellation).

[333] “Her appearance, now in the morning, and now in the evening.”
_Conv._ II. xiv. 114, 115.

                                        “la stella
    Che il sol vagheggia or da coppa or da ciglio.”[334]

[334]
                                  “The star
    That woos the sun, now following, now in front.”
                    _Par._ viii. 11-12.  (_Longfellow_).

Mercury and Venus (called rather oddly after their mothers), are said
both to move closely round the sun:—

               ... “vidi com’ si move
    Circa e vicino a lui Maia e Dione.”[335]

[335]
        “I saw how move themselves,
    Around and near him, Maia and Dione.”
                             _Par._ xxii. 143-144.

“Quel bel pianeta di Mercuro”[336] keeps closest, for he is more
hidden than any other in the rays of the sun. Here again the fact is
expressed in simple prose in the _Convivio_:—

[336]
    “That fair planet, Mercury.”
                             _Son._ xxviii. 9.

    “Mercurio ... più va velata de’ raggi del sole che
    null’ altra stella.”[337]

[337] “Mercury ... as it moves is more veiled by the rays of the sun
than any other star.” _Conv._ II. xiv. 99-100.

which explains (if necessary) the more poetical language of the
_Paradiso_:—

                                “La spera,
    Che si vela ai mortal con altrui raggi.”[338]

[338]
                         ... “The sphere
    That veils itself from men in alien rays.”
                   _Par._ v. 128, 129.

In the same way we may compare the descriptions of Mars in the
_Paradiso_ with a statement in the _Convivio_:—

            “Questo fuoco,”[339] and “l’affocato riso della
            stella,”[340] and “Marte rosseggia,”[341] with

[339] “This Fire.” _Par._ xvi. 38.

[340] “The burning smile of the star.” _Par._ xiv. 86.

[341] “Mars shows red.” _Purg._ ii. 14.

        “Esso Marte ... il suo calore è simile a quello del
        fuoco; ... esso appare affocato di colore.”[342]

[342]
    “This Mars ... his heat is like the heat of a fire ...
     his colour is as if he were on fire.”
                               _Conv._ II. xiv. 162-165.

The famous occultation of Mars by the moon, seen by Aristotle, is
quoted by Dante in _Conv._ II. iii. 59-65.

Jupiter is the “dolce stella”[343] and the “giovial facella.”[344] He
is silvery white, the whitest of all the stars:—“Intra tutte le stelle
bianca si mostra, quasi argentata.”[345]

[343] “Sweet star.” _Par._ xviii. 115.

[344] “The torch of Jove.” _Par._ xviii. 70.

[345] “Amongst all the stars it shows white, as if silvered over.”
_Conv._ II. xiv. 202-204.

Therefore when Dante saw the planet filled with brilliant spirits,
he says: “Giove pareva argento lì d’ oro distinto.”[346] Comparisons
between the colours of Jupiter and Mars are made in _Par._ xviii.
64-69, and xxvii. 13-15.

[346]
                                    “Jupiter
    Seemed to be silver there with gold inlaid.”
                      _Par._ xviii. 95-96. (_Longfellow_).

Finally Saturn is the slowest and the most distant of all the planets.
These two characteristics are thus described in the _Convivio_:—

    “L’una si è la tardezza del suo movimento per li
    dodici segni; chè ventinove anni e più, secondo le
    scritture degli astrologi, vuole di tempo lo suo
    cerchio: l’altra si è che esso è alto sopra tutti
    gli altri pianeti.”[347]

[347] “One is the slowness of its movement through the twelve signs;
for twenty-nine years and more, according to the writings of the
astrologers, are required for its revolution: the other is that it is
high above all other planets.” _Conv._ II. xiv. 226-231.

In the _Paradiso_ Saturn is called a Mirror,[348] a Crystal,[349] a
splendour;[350] his circling motion is alluded to, and his position at
the time in the zodiac:—

[348] _Par._ xxi. 18.

[349] _Par._ xxi. 25.

[350] _Par._ xxi. 13.

      “Cerchiando il mondo.”[351]
      “Sotto il petto del Leone ardente.”[352]

[351] “Circling the world.” _Par._ xxi. 26.

[352] “Beneath the burning Lion’s breast.” _Par._ xxi. 14.

Some of the most beautiful similes in the _Divine Comedy_ are drawn
from the planets. The angel-pilot of Purgatory, when first seen far
off over the sea, is likened to the planet Mars, glowing red through
morning mists, low in the west above the ocean floor;[353] and the
angel that welcomes the poet to the second circle on the Mountain is
beautiful as the Morning Star.

[353] _Purg._ ii. 13-15.
    “A noi venia la creatura bella,
     Bianco vestita, e nella faccia quale
     Par tremolando mattutina stella.”[354]

[354]
    “Towards us came the being beautiful,
     Vested in white, and in his countenance
     Such as appears the tremulous morning star.”
                           _Purg._ xii. 88-90. (_Longfellow_).

Although any of the planets when rising just before the sun may be
called a morning star, Venus is probably intended here, as also where
St. Bernard, in his devotion to the Virgin, is compared with the
Morning Star which takes its beauty from the sun:—

    “Colui ch’abbelliva di Maria,
     Come del sole stella mattutina.”[355]

[355] “He who drew beauty from Mary, as the Morning Star does from the
Sun.” _Par._ xxxii. 107, 108.

All the seven planets (that is, including sun and moon), are
occasionally mentioned together, “tutti e sette,”[356] and their
movement in the ecliptic is referred to in _Par._ x, 14: “L’obbliquo
cerchio che i pianeti porta.”[357] In the 14th and 15th chapters of
the second treatise of the _Convivio_, already so often quoted, Dante
draws an elaborate comparison between the seven planets and the seven
sciences of the Trivium and Quadrivium. The moon is Grammar, Mercury
Dialectic, Venus Rhetoric, the Sun Arithmetic, Mars Music, Jupiter
Geometry, and Saturn Astrology. The reasons given for the latter are
the slow movement and the height (_i.e._ distance from Earth) of
Saturn, which Dante compares with the length of the time taken in
learning astronomy, and the loftiness of its subject.

[356] “All the seven.” _Son._ xxviii. 14, and _Par._ xxii. 148.

[357] “The oblique circle which carries the planets.”

In the same way the star sphere is said to resemble Physics and
Metaphysics, the Primum Mobile Ethics, and the Empyrean Theology. The
argument is very fanciful, but just what would appeal to readers of
Dante’s day, who loved to find allegories everywhere; and it gives him
an opportunity of instructing them very simply in his beloved science.

He sometimes uses the planetary periods as divisions of time (as Plato
said they should be used), for computing earthly events, and in him
this does not seem affectation, as it would with almost anyone else. It
seems quite natural that Cacciaguida, when speaking in the heaven of
Mars, and answering a question regarding the date of his birth, should
count the time not by solar but by Martian years, saying that from
the beginning of the Christian Era to the day of his birth, Mars had
returned to his Lion (the constellation of Leo) five hundred and eighty
times.[358] The length of the Martian year according to Alfraganus is
1 Persian year, 10 months, and 22 days nearly. The Persian year (as
he tells us in the first chapter of the _Elementa_) consists of 12
months of 30 days each plus 5 extra days, making 365 days exactly (not
365¼ days like the Roman), so the Martian year is 687 days (the modern
estimate is 686·9). 687 days × 580 gives us 1091 a.d. as the date of
Cacciaguida’s birth. This is consistent with the date of his death, for
he had just told Dante that he fell in the Crusade to which he followed
the Emperor Conrad, and we know that this was fought in the year 1147.

Some commentators think that Dante did not intend the Martian year
to be taken so precisely, but only as approximately two solar years,
since he gave it thus in _Conv._ II. xv. 145. But there he specially
states that he is quoting an approximate figure only (“uno anno
quasi”[359] is half the period of Mars) whereas in the _Paradiso_ it
is used to fix a date. Since by taking 580 × 2 years we get 1160, an
impossible date of birth for a man who died in 1147, the only way to
support this theory that Dante was speaking loosely here is to adopt
another reading of the passage, and substitute “tre” for “trenta.”[360]
Then 553 (instead of 580) × 2 years would give the date 1106; but the
reading is not supported by good authority.

[358] _Par._ xvi. 34-39.

[359] “About a year.”

[360] “Three,” for “thirty.”

The period of Venus is used with equal appropriateness when Dante is
relating how love for the Gentil Donna found a way to his heart, coming
on the rays of Venus,[361] the star of love.

    “La stella di Venere due fiate ere rivolta in
    quello suo cerchio che la fa parere serotina e
    mattutina, secondo i due diversi tempi, appresso
    lo transpassamento di quella Beatrice beata, che
    vive in cielo con gli angioli e in terra colla mia
    anima, quando quella Gentil Donna, di cui feci
    menzione nella fine della _Vita Nuova_, apparve
    primamente accompagnata d’Amore agli occhi miei, e
    prese alcuno luogo nella mia mente.”[362]

[361] _Conv._ II. vii. 88, 89.

[362] “The star of Venus had twice revolved in that circle of hers
which makes her appear as evening and morning star, according to her
two seasons, since the translation of that holy Beatrice who lives in
heaven with the angels and on earth in my soul, when that Gentle Lady,
of whom I made mention at the end of the ‘New Life,’ appeared first
before my eyes, escorted by Love, and took some place in my mind.”
_Conv._ II. ii. 1-12.

Venus runs through her changes, appearing first as Evening and then
as Morning star, in 584 days; and, as the reader will remember,
this movement was ascribed by Ptolemy to her epicycle (“quello suo
cerchio,” “that circle of hers”). Dante would find 584 days given for
it in his Alfraganus.[363] Twice 584 is 1168 days, or three years and a
little more than 2 months. Therefore, since we know from _V. N._ xxx.
that Beatrice died in June 1290, Dante wishes to say that he first saw
the Lady of Pity in August 1293.

[363] “Venus [ambitum epicycli peragit] anno Persico 1, mensibus 7,
et diebus prope 9,” that is, the period of Venus on her epicycle is
365 + 210 + 9 = 584 days nearly, according to Alfraganus. The modern
mean value is also 584 days.

The period has been taken by some modern commentators to refer to the
225 days in which Venus revolves round the sun, but this period has no
place in the Ptolemaic system. We cannot here discuss Dante’s allegory
of the Gentle Lady and Philosophy, but in this passage he has stated
without ambiguity or uncertainty the date of her first appearance.[364]

[364] See Lubin’s _Dante e gli Astronomi Italiani_. The period of 225
days may be easily deduced from Ptolemy’s system, for it is the time in
which the epicycle of Venus would make an absolute revolution round its
centre, the diameter becoming parallel to its former position. But the
Greeks invariably reckoned the period as the time in which it revolved
relatively to Earth, that is 584 days.

6. ECLIPSES.

We find solar eclipses mentioned six times in Dante’s works. As in all
old records, there is no allusion to the features which chiefly strike
modern astronomers—the pearly corona, and the blood-red prominences
standing out like flames round the black disc. The terror of the sudden
darkness, even when foreseen, seems to have absorbed all attention,
and only the appearance of stars in the daytime and the frightened
behaviour of animals was noted by Ristoro, and by others until quite
modern times.

In his letter to the Cardinals of Italy, Dante speaks of the shameful
and grievous removal of the Papacy from Rome to Avignon as an eclipse
of the sun.[365] In his dream of the death of Beatrice, he sees the sun
so darkened that the stars appear, to his great terror:—

[365] _Ep._ viii. 158, 159.

    “Poi mi parve vedere appoco appoco
    Turbar lo Sole ed apparir la stella.”[366]

[366]
    “The while, little by little, as I thought,
     The sun ceased, and the stars began to gather.”
                      _V. N._ xxiii. 176, 177. (_Rossetti_).

See also the prose description just before, lines 35-37.

He also refers to the disputed idea that the darkness at the time of
the Crucifixion was caused by an eclipse of the sun,[367] and to the
figurative eclipse which then took place in heaven.[368]

[367] _Par._ xxix. 97-102.

[368] _Par._ xxvii. 35, 36.

If he had ever seen one in reality, it would have made more impression
upon him, and we should surely have found it referred to several times
and vividly described. The only suggestion of a personal experience is
where he temporarily loses the power of sight by gazing too fixedly
upon the spirit of St. John; and he compares this to a man who looks so
intently at the sun, just before an eclipse, that he becomes incapable
of seeing it at the critical moment.[369] This incident may have been
told him by an observer of the total eclipse of June 1239, which was
visible in Italy, and seems to be the one described by Ristoro.

Lastly, he mentions the discovery that the moon comes between us and
the sun, which we have learned from eclipses, as an example of the
proper method of reasoning: for we must first ask whether a thing is,
and afterwards why it is. Thus man’s wonder leads him to knowledge.[370]

[369] _Par._ xxv. 118-121.

[370] _Qu._ xx. 3-5, 26-29.

The eclipsed moon is only once mentioned, viz. in _De Mon._ III. iv.
140-142, where she is described as not wholly dark. With his usual
indifference to her Dante fails to note the often extraordinary beauty
of her colouring when the eclipse is total.

7. COMETS AND METEORS.

The connection between these two classes of heavenly bodies seems to be
real, though its exact nature is still a mystery. In old days little
or no distinction was drawn between them, so that it is sometimes
difficult to know whether a writer is describing a large meteor, or a
comet, or a shower of falling stars.

Dante only mentions comets once, very briefly, when he describes
spirits in Paradise as “fiammando forte a guisa di comete.”[371] He
says nothing of the magnificent comet described by Ristoro, which
rose at three o’clock in the morning, huge as a mountain, and with
great rays like a mane; but travelling always towards the south grew
gradually fainter, and disappeared after 60 days. Yet it was seen in
Tuscany shortly before Dante’s birth, and it was thought to herald the
death of the Pope (Urban IV. in 1264) and the terrible war in which
first Manfred and afterwards Conradin were slain. These events are
familiar to every reader of the _Divine Comedy_,[372] but there is
never any mention of the comet.

[371] “Blazing brilliantly like comets.” _Par._ xxiv. 12.

[372] _Inf._ xxviii. 16-17; _Purg._ iii. 112-132.

Nor does he describe in any detail the fiery cross which was seen in
the sky above Florence “in the beginning of her destruction,” which
does not mean, as one might think, the legendary sack of the city
by Totila, but the treacherous entry of Charles of Valois, “Totila
secundus,”[373] in November 1301. This portent was of course considered
as of ill omen for the Republic, and although Dante was still absent
on his embassy to Rome, and cannot have seen it himself, it is rather
remarkable that he says so little about it. It is described by an
eye-witness, “Io, che chiaramente la viddi”[374] as a red cross which
appeared in the evening over the Priors’ Palace; the vertical arm
seemed to be 20 ells long, the transverse one a little shorter, and
it remained visible for as long as it would take a horse to gallop
two furlongs. Villani the historian describes it as like a comet with
an immense trail, as of smoke, behind it. Dante merely mentions it,
together with the ball of fire seen by Seneca at the death of Augustus,
which, judging by Seneca’s own words, was also a large meteor, for
he describes it as flashing into sight and moving very rapidly,
disappearing as it moved.[375]

[373] _V. E._ II. vi. 48.

[374] “I, who saw it clearly.”

[375] _Naturales Quæstiones_, Bk. I.

Dante calls meteors “kindled vapours,”[376] in accordance with the
doctrines of Aristotle, but the popular idea of them is shown by his
observation that they might be taken for stars in motion, only that
no star vanishes from its place, and they are only seen for a short
time.[377] Ristoro d’Arezzo had already alluded to this fallacy:—

[376] _Conv._ II. xiv. 168-171, and _Purg._ v. 37.

[377] _Par._ xv. 16-18.
    “Alquanti non savi credono ch’elle sieno stelle,
     che caggino del cielo e vengano meno.”[378]

[378] “Some ignorant people think that they are stars which fall from
heaven and vanish.” _Comp. del Mondo_, VII. v.

He gives the same reason as Dante for disbelieving this, and Seneca had
expressed it more forcibly, saying that if true there would be no more
stars in the sky, for some meteors are seen every night.

Albertus Magnus, who seems to have had a genius for mistaking his
authorities, quotes Alfraganus as stating that shooting stars are most
frequent in evening twilight, though nothing of the kind is said in the
_Elementa._ Dante perhaps accepted the statement, though it is by no
means necessarily implied in his “di prima notte:”[379] moreover there
is some authority for the alternative reading of “mezza notte.”[380]
Wherever the idea originated, its sole foundation must have been the
circumstance that more persons are awake in the early than in the late
hours of the night: the fact is that more meteorites are captured by
the morning side of the earth, which is turned in the direction towards
which she is moving in her orbit.

[379] “Early in the night.”

[380] “Midnight.” _Purg._ v. 38.

Shooting stars were necessarily familiar to a lover of starry skies,
and Dante has given us an exquisite description of the suddenness with
which they startle quiet eyes, while their brilliancy and swiftness of
flight provides him with two beautiful similes.

In the first he compares them, and also flashes of summer lightning,
with messenger spirits in Purgatory hastening to bring their friends to
him:—

    “Vapori accesi non vid’ io sì tosto
       Di prima notte mai fender sereno,
       Nè, sol calando, nuvole d’agosto,
     Che color non tornasser suso in meno,
       E giunti là, con gli altri a noi dier volta.”[381]

[381]
    “Vapours enkindled saw I ne’er so swiftly
       At early nightfall cleave the air serene,
       Nor, at the set of sun, the clouds of August,
     But upward they returned in briefer time,
       And on arriving with the others, wheeled
       Towards us.”
                        _Purg._ v. 37-41. (_Longfellow_).

(By “vapours that cleave the clouds of August,” flashes of lightning
without thunder are meant. Aristotle believed both these and meteorites
to be ignited vapours).

The second illustrates the brightness and beauty, as well as the
movement, of the star-like spirits in Mars:—

    “Quale per li seren tranquilli e puri
       Discorre ad ora ad or subito foco,
       Movendo gli occhi che stavan sicuri,
     E pare stella che tramuti loco,
       Se non che dalla parte ond’ ei s’ accende
       Nulla sen perde, ed esso dura poco ...”[382]

[382]
    “As through the pure and tranquil evening air
       There shoots from time to time a sudden fire,
       Moving the eyes that steadfast were before,
     And seems to be a star that changeth place,
       Except that in the place where it is kindled
       Nothing is missed, and this endureth little.”
                         _Par._ xv. 13-18. (_Longfellow_).

8. THE SUN’S PATH IN THE SKY SEEN FROM DIFFERENT PARTS OF THE EARTH.

We have now seen how familiar Dante was with the aspects of the skies
above his head. His writings show also that he had pictured clearly
to himself what they must be in other parts of the world—in regions
far east or west, in the southern hemisphere, at the equator, and at
either pole. Science could not tell him all that he would have liked to
know about the stars, so that although he can speak of regions where
Ursa Major passes overhead, and where it sinks out of sight below
the horizon, he has to fall back upon his imagination and invent new
constellations for the southern hemisphere.

But astronomy could tell him, and his habit of accurate thought,
as well as his imagination, helped him to grasp how the sun would
appear at any latitude on the earth, and what would be the results on
the length of day and night, and on the seasons. A very interesting
little disquisition on this subject is found in the _Convivio_, in
illustration of some lines in one of his Odes, which speak of the sun
circling the whole world. In order to understand this completely, Dante
says, we must know exactly in what way the sun circles the world. The
chief point to bear in mind while reading his description is that the
sun, besides the simple daily motion in a circle, has a constant slow
motion north or south, and therefore his path in the sky, as we see it
day after day, is really spiral.

The passage is much too long to quote in full, but if the reader will
follow me, taking his _Convivio_ and opening it at chapter v. of
Treatise III. and beginning at line 66, I will give a résumé which will
form a running commentary on the text, and an explanation of any points
which may not at once be clear.

We see the sky, says Dante, continually revolving round Earth as
centre; and it has two fixed poles of revolution—the northern, which is
visible to nearly all the land not covered by sea, and the southern,
which is hidden from nearly all of it. And the circle which is
equi-distant from these two poles [the celestial equator] is that part
of the sky in which we see the sun when he is in Aries and in Libra.

Now if a stone could be dropped from this pole of ours [the northern],
it would fall far away yonder in the ocean just where, if a man were
standing, he would always have the Pole Star exactly overhead. [“La
stella”[383] is the Pole Star, see p. 291]. And I believe (Dante says)
that from Rome to the north pole, in a direct line, is a distance
of about 2,700 miles. To fix our ideas, let us imagine that at this
spot there is a city called _Maria_, and let us imagine another city,
called _Lucia_, at the spot exactly opposite, where a stone would
fall if dropped from the other pole. And I believe that from Rome
southwards to this second place would be a distance of about 7500
miles. Thus the distance between the two cities, in whatever direction
the measuring cord be stretched, would be 10,200 miles, that is, half
the circumference of the globe,[384] and the inhabitants of _Maria_
would have their feet opposite the feet of those of _Lucia_. [If any
two spots on a sphere are exactly antipodal, but in no other case, the
distance may be measured in an infinity of directions, and always come
out the same.]

[383] “The star.”

[384] As this is the value given by Alfraganus, we must here understand
Arabian miles. The distances from Rome to the north and south pole are
therefore probably equal to 3500 to 9750 English miles, and both are a
little too large, because the half circumference of Earth is too large.
The proportion is about right, however, for Rome is nearly three times
as far from the south pole as the north, her latitude being 42° N.
Alfraganus placed her in the fifth climate, at the northern boundary of
which he said the pole was elevated 43½°.

Lastly, let us imagine a circle on the globe, which will be at equal
distances everywhere from _Maria_ and _Lucia_ [the equator]. According
to the opinions of the astrologers, if I understand them aright,
and according to what is said by Albertus Magnus and by Lucan, this
circle would divide the dry land from the ocean there in the south,
approximately along the extremity of the First Climate, where amongst
others live the Garamantes, who go almost always naked, to whom Cato
went when fleeing from Cæsar.

“Approximately,” because the southern extremity of the First Climate,
according to Alfraganus, lay a little north of the equator, although
land extended, and was sparsely inhabited, as far the equator (see p.
186).

Dante speaks again of these extra-climatal races in _De Mon._ I. xiv.
43-51, where he contrasts the Scythians who live beyond the seventh
climate, and therefore endure extreme inequality of days and nights,
and suffer almost intolerable cold, with the Garamantes who live under
the equator, where days and nights are always equal, and the heat
is so intense that they can scarcely bear any clothing. Since “the
astrologers who determine the climates”[385] had fixed their northern
limit at 50½°, nearly the whole of Britain also lay, like barbarous
Scythia, in this scarcely habitable region of long nights and bitter
cold!

[385] _Qu._ xix. 36.

When we have marked these three places on the globe, _i.e._ the two
poles and the equator, it is easy (Dante goes on) to see how the sun
circles. I say then, that the heaven of the sun turns from west to
east, not directly against the diurnal movement—that is, the movement
which produces day and night—but obliquely against it, and so that its
middle circle, which is similarly between its two poles, and on which
is the body of the sun [_i.e._ the ecliptic], cuts in two opposite
points the circle of the two first poles [the equator], that is, at the
beginning of Aries and the beginning of Libra; it diverges from that
circle in two arcs, one north and the other south. The highest points
of these arcs are equally distant from the first circle in either
direction, being 23 degrees and a little more; and the one summit is at
the beginning of Cancer, and the other at the beginning of Capricorn.

Therefore, when the sun is in the beginning of Aries, travelling in
the mid-circle of the first poles [the equator], _Maria_ will see this
sun circling the world, low down on the ground, or on the sea, like
a mill-stone only half of which is seen, and day after day he will
be seen to rise, like the screw of a press, until he has performed
about ninety revolutions, or a little more. When these revolutions are
accomplished, he will be as high in the sky above _Maria_ as he stands
in the sky of the Garamantes at middle-tierce at the time of equal days
and nights.[386]

[386] Adopting the reading of Dr. Moore: “nella mezza terra, alla mezza
terza,” that is, “at the equator at middle-tierce.” See _Studies in
Dante_ III. 107, 108.

[From _Conv._ IV. xxiii. and III. vi., where Dante explains the use
of temporal hours, we learn that mid-tierce on the day of the equinox
is an hour and a half after sunrise, or 7.30 A.M. Since the sun moves
through 360 degrees divided by 24, that is 15 degrees, in an hour,
and his motion is vertical in equatorial countries at the equinox,
it would bring him in 1½ hours to 22½ degrees above the horizon. His
greatest height above the horizon at the pole is only one degree more
than this, for it is obviously equal to the greatest distance between
the equator and the ecliptic, _i.e._ 23½ degrees, since at the pole the
equator coincides with the horizon. This gives a good idea, therefore,
of the appearance of the sun in the sky to the people at _Maria_, and
is a striking illustration of the difference between the polar sun and
the equatorial. For at the time mentioned, the sun has only a quarter
the height which it will attain at noon, when it will pass through the
zenith of the Garamantes; yet this is the highest position in which the
inhabitants of _Maria_ can ever see it].

If a man stood upright in _Maria_, and kept turning his face to the
sun, he would see it move to his right [as we do].

After reaching his greatest height in the sky, the sun would begin to
descend again, in the same spiral way like a screw turning, for another
ninety revolutions or so, until once more he was circling down on the
horizon, only half his body visible.

Then he would be lost to sight altogether, and would begin to be seen
in _Lucia_, where he would rise and descend in just the same way as in
_Maria_. But if a man faced the sun in _Lucia_, he would see it moving
to his left [as one does in Australia where it goes north at noon].

[Illustration: Fig. 43. The Sun at the Equinox, seen from the poles and
the equator. _Conv._ III. v.

(Maria, Lucia, imaginary cities at the North and South poles).]

We see, then, that these places have one day in the year which is six
months long, and one night of equal length, and when it is day with
one, it is night with the other.

Now on the circle on the globe where the Garamantes live [the equator],
the sun when in Aries goes exactly overhead, not circling horizontally
like a mill-stone, but vertically like a wheel, and exactly half of
this wheel is visible above the horizon.

After this, the sun is seen to depart and go towards _Maria_ for about
91 days; then in about the same time it returns, and enters Libra; then
it goes towards _Lucia_ for about 91 days, and in the same period
returns. And this place, which circles the entire globe, always has
equal day and night, on whichever side of it the sun is; and twice in
the year it has a very hot summer, and twice a mild winter.

The regions which are between the two imaginary cities and the
mid-circle, see the sun in different ways, according to their distance
from these places, but the details, our author says, he will leave to
the ingenious reader,

    “Siccome omai, per quello che detto è, puote vedere
    chi ha nobile ingegno, al quale è bello un poco di
    fatica lasciare.”[387]

[387] “For now, after what has already been said, the rest may be
understood by whomsoever has a noble mind, to which it is well to leave
a little labour.” (_Cf. Par._ x. 22-25).

He draws attention to the interesting fact, which follows from the
above, that in the course of a year (when the heaven of the sun has
made a complete revolution and returned to the same place), every
part of this globe on which we live has received an equal amount of
daylight. And the essay ends in an apostrophe which recalls the reproof
of Virgil to those who will not look up to the skies:[388]

    “O ineffabile Sapienza che a così ordinasti, quanto
    è povera la nostra mente a Te comprendere! E voi,
    a cui utilità e diletto io scrivo, in quanta
    cecità vivete, non levando gli occhi suso a queste
    cose, tenendoli fissi nel fango della vostra
    stoltezza.”[389]

[388] _Purg._ xiv. 148-151.

[389] “O unspeakable Wisdom who hast thus ordained, how poor is our
intellect to understand Thee! And you, for whose benefit and pleasure
I am writing, in what blindness you live, not lifting up your eyes to
these things, but keeping them fixed on the slough of your folly.”

It is interesting to compare this passage with the parallel passages
in Alfraganus and Ristoro. The astronomer is concise and clear; the
monk is diffuse and apt to repeat himself; the poet is quaintly
picturesque. Both the Italians evidently draw the main facts from
the Arab, and all use the illustration of a mill-stone to explain
the horizontal motion of the heavens at the pole: here are the three
corresponding passages:—

           “Coelumque molæ trusatilis instar gyrum
            vertitur.”[390]

           “Lì si volgera il cielo attorno con tutte le sue
            stelle, in modo di macina.”[391]

           “Conviene che _Maria_ veggia ... esso sole ‘girare
            il mondo’ ... come una mola.”[392]

[390] “And the sky revolves like a mill-stone.” _El. Ast._ ch. vii.

[391] “There the sky will revolve, with all its stars, mill-stone
        fashion.” _Comp. del Mondo._ I. xxiii.

[392] “It follows that _Maria_ must see this sun ‘circling the world’
like a mill.” _Conv._ III. v. 142-147.

Dante alone uses the figure of a wheel to illustrate the vertical
motion at the equator; he perhaps takes from Ristoro the idea of
the spiral. For the latter describes the path of the sun as a “via
tortuosa, la quale i savi chiamano spira;”[393] but he explains it as
like a string wound round a stick, Dante like the screw of a press.
Dante is dealing only with the sun, and does not enter into details
about the visibility of the zodiacal signs like the other two authors;
but on the other hand he goes south to the other pole, which apparently
does not interest the others, perhaps because the southern hemisphere
was thought to be uninhabited. But the poet has added life to his
description by supposing both poles inhabited, placing there his
imaginary, mysteriously-named cities of “Maria” and “Lucia.” On the
equator, where Ristoro has the mythical city of Arym, whose wise and
prosperous citizens enjoy a perfect climate, Dante, relying more on the
classics, lets his barbarous Garamantes run about naked most of the
year, under the fierce equatorial sun.

Needless to say, his little homily in conclusion is all his own;
it is more interesting to find that he alone mentions the opposite
movements of the Sun, to right and left respectively in the north and
south hemispheres,[394] and the fact that every part of the earth
receives the same amount of sunlight in a year. This may have been
suggested by someone else, but one would like to think he arrived at it
independently, when thinking over the facts.

[393] “A winding path, which the learned call a spiral.”

[394] “Lucan, who was well known to Dante, had observed that shadows
cast by the sun in the southern hemisphere travel to the right instead
of to the left, and fall southwards when with us they fall to the
north.” Moore, _Studies in Dante_ i. p. 239.

In the light of this treatise, which describes so truthfully the path
of the sun, and its effect on the seasons in different latitudes, we
may explain two rather puzzling passages in the _Divine Comedy_.

One is at the beginning of the tenth canto of the _Paradiso_, where
Dante wishes his readers to realize the position of the sun when he
entered it with Beatrice, and the great importance of this position.
“Lift your eyes with me, reader,” he says, “to that place in the lofty
heavens where the one motion meets the other, and see how the oblique
circle which carries the planets branches off from that point.” The
reader is now familiar with the “two chief motions,” and knows that one
is the diurnal, from east to west, the other the planetary periodical
motions in the opposite direction; they meet at the equinoxes, where
the ecliptic cuts the equator. It is the spring equinox which Dante is
speaking of, for a little further on he says that the sun, situated
in the place above-mentioned, was circling in those spirals which
bring him to us earlier every day (lines 31-33). Now if the path
of the planets were not thus oblique, he continues, much virtue in
heaven would be lost, and almost every earthly power dead. Even if the
obliquity were merely less or more, the universal order of both heaven
and earth would suffer greatly. But why this should be so he leaves his
readers to think out for themselves, having a greater matter in hand
which demands all his attention.

It is easy to see that if the sun always moved in the equator, without
departing from it either north or south, he would rise every day to
the same height in the sky, and there would be no change of seasons
anywhere on the earth; he would always be overhead at noon to Dante’s
Garamantes, living on the equator, and always just on the horizon, day
and night, to the people of “Maria” and “Lucia” at the Poles. If the
ecliptic made a greater angle with the equator the seasons would be
more marked, and the sun would rise higher in summer in high latitudes.
If the angle were less, the reverse would be the case. Moreover if sun
and moon and all the planets followed the same track, they would be
constantly eclipsing one another.

But if we would understand the full meaning of—

    “Se la strada lor non fosse torta,
     Mota virtù nel ciel sarebbe in vano,
     E quasi ogni potenza quaggiù morta.”[395]

[395]
    “If their pathway were not thus inflected,
     Much virtue in the heavens would be in vain,
     And almost every power below here dead.”
                          _Par._ x. 16-18. (_Longfellow_).

we must turn to thirteenth-century Ristoro of Arezzo, who has set forth
in detail the results which he believed would follow from a change in
the ecliptic. If all the seven planets moved in the same narrow path,
there would be much less variety in their “aspects,” and therefore
in their influences upon the earth; and in the frequent eclipses one
would prevent the other from looking at the earth (“impedimenterebbe
l’uno l’altro a guardare la terra”), and so hinder its action. And
since it is the northward movement of the sun which causes our plants
to blossom, and later to bear fruit, if there were no such motion we
should see no renewal of life. He argues further that if the obliquity
of the ecliptic were greater, countries in high latitudes would have
too severe a winter to be inhabited; while if it were less, the summer
there would not be warm enough for the ripening of harvests; therefore
in whichever way it differed from the actual value, a smaller part of
the earth would be habitable.

    “Or ti riman, lettor, sopra il tuo banco,
    Dietro pensando a ciò!”[396]

[396]
    “And now remain, reader, on your bench, thinking over this!”
                                           _Par._ x. 22, 23.

How much of this was in Dante’s mind it is hardly possible to say,
but it is evident that the “via tortuosa” of the seven planets, and
its effects on the earth, was a favourite subject for thought in his
time.[397]

[397] Thus Petrarch: “Le stelle vaghe e lor viaggio torto.” (“The
wandering stars and their winding way.”) _Sonetto de Morte di Madonna
Laura._

But the most famous passage relating to the sun’s path and its aspect
in strange latitudes is _Purg._ iv. 52-84.

Here Dante is able at once to understand the startling appearance
of the sun travelling to his left instead of his right, as seen on
the first morning in Purgatory, for he grasps the full meaning of
Virgil’s explanation, and caps it, in a way which seems astonishingly
quick-witted to unastronomical readers!

The two poets had begun to climb the mountain just at sunrise, and sat
down to rest on a ledge at about half-past nine, looking east. Dante
at first looked down at the shore, whence he had so painfully climbed,
then raised his eyes to the sun, and was amazed to find that its rays
struck him on the left shoulder.

Virgil, seeing his astonishment, explains why the sun is going north
instead of south as it climbs the sky. The sun is now in Aries, and
therefore on the equator, as we know from several passages, but Virgil
begins by saying that if it were in Gemini [a more northerly sign] and
kept to its ancient path, Dante would see it travelling still further
northwards in its daily course. “If Castor and Pollux [stars in Gemini]
were in company with that Mirror [the sun] which carries his light up