The sun already burned at the horizon,
while the high point of its meridian circle
covered Jerusalem, and in opposition
equal Night revolved above the Ganges
bearing the Scales that fall out of her hand
as she grows longer with the season's changes:
thus, where I was, Aurora in her passage
was losing the pale blushes from her cheeks
which turned to orange with increasing age. (II. 1-9)
Ciardi helpfully points out, "The bit of erudite affectation in which Dante indulges here means simply, 'It was dawn' " (p.194, note to II. 1-9).
And just in case you were wondering:
To understand the total figure, one must recall the following essentials of Dante's geography: (1) Jersualem is antipodal to the Mount of Purgatory. Thus it is sunset at Jerusalem when it is sunrise on the mountain. (2) All the land of the earth is contained in one half of the Northern Hemisphere. That is to say, there is no land (except the Mount of Purgatory) anywhere in the Southern Hemisphere and of the total circle of the norther Hemisphere (360 degrees) only half (180 degrees) is land. Jerusalem is at the exact center of this 180 degree arc of land. Spain, 90 degrees to one side, is the West, and India (Ganges), 90 degrees to the other, is the East.
Every fifteen degrees of longitude equals one hour or time. That is to say, it takes the Sun an hour to travel fifteen degrees. Thus at sunset over Jerusalem it is midnight (six hours later) over India, and noon (six hours earlier) over Spain. The journey, moreover, is conceived as taking place during the vernal* equinox, when the days and nights are of the same length. Thus it is "equal Night' (line 4).
Finally, when the Sun is in Aries, midnight is in Libra (the Scales). Thus the night bears the Scales in her hand (i.e., that constellation is visible), but Libra will no longer be the sign of the night as the season changes, and thus it may be said that the Scales will fall from her hand (i.e., will no longer be visible.
That's very helpful, Ciardi... or at least, it would have been if I'd cared at all about what exactly Dante was getting at there. The text is full of similar passages and notes; I won't quote all of them because I know you wouldn't read them. Nor do I blame you.
Ok, maybe one more example. Just trust me that the entire book is filled with these sorts of things:
Virgil was quick to note the start I gave
when I beheld the Chariot of the Sun
driven between me and the North Wind's cave.
"Were Castor and Pollux," he said, "in company
of that bright mirror which sends forth its rays
equally up and down, then you would see
the twelve-toothed cogwheel of the Zodiac
turned till it blazed still closer to the Bears
--unless it were to stray from its fixed path. **
If you wish to understand why this is so,
imagine Zion and this Mount so placed
on earth, the one above, the other below,
that the two have one horizon though they lie
in different hemispheres. Therefore, the path
that Phaethon could not follow in the sky
must necessarily, in passing here
on the one side, pass there upon the other,
as your own reasoning will have made clear."
And I then: "Master, I may truly vow
I never grasped so well the very point
on which my wits were most astray just now:
that the mid-circle of the highest Heaven,
called the Equator, always lies between
the sun and winter, and, for the reason given,
lies as far north of this place at all times
as the Hebrews, when they held Jerusalem
were wont to see it toward the warmer climbs." (IV. 58-84)
I'll spare you Ciardi's notes on all this, because I can't imagine why anyone would care. Suffice to say that they're approximately nine million paragraphs long and contain this hilarious diagram of the earth with Zion, the equator, the path of the ecliptic, Purgatory, and the "celestial horizon of Purgatory and Zion" all carefully marked.
There is, however, at least one of Dante's little digressions on time and geography that I find utterly delightful. At the end of a conversation with the indolent Belacqua in Canto IV (Ante-Purgatory: The First Ledge -- The Late-Repentant -- Class Two: The Indolent) (hell of an ordering system they've got there, eh?), Dante is reminded that he must keep going:
But now the Poet already led the way
to the slope above, saying to me: "Come now:
the sun has touched the very peak of day
above the sea, and night already stands
with one black foot upon Morocco's sands." (IV.136-41)
It was now noon at Purgatory. It must therefore be midnight in Jerusalem. Dante believed Morocco to lie exactly 90 degrees west of Jerusalem (in the same longitude as Spain) and 90 degrees west of midnight is six hours earlier. Hence, it is six o'clock there and night would just be beginning. (p. 207, note to ll.136-140)
I love these lines so much! I picture Night wearing a lone black sock, like maybe the other one got eaten by the dryer. Or Night coming "on little cat feet" (this is the first poem I remember learning -- I think we read it in kindergarten). Carl Sandburg, 'fess up. Did you borrow from Dante?
*My edition is old and full of typos; the text here actually reads "venal Equinox." Which is a hilarious image and could be a good name for a band.
**Apparently this line is Dante's idea of what passes for humor. Horrifying.