In all the Divine Comedy there is no more beautiful allegory than this. Man in the age of innocence, man to-day when purified from sin, is already partly in heaven, though he still walks the earth. And like many another allegory of Dante’s, it follows naturally from the science of his day. Aristotle had said that the upper air “flows in a circle, because it is drawn along with the circulation of the Whole,” and Aquinas:—
“Thus the air which exceeds the greatest altitude of the mountains flows round, but the air which is contained within the altitude of the mountains is impeded from this flow by the immoveable parts of Earth.”
Purg. xxviii. 103-108 is almost a poetical paraphrase of this:—
“ ... In circuito tutto quanto L’aer si volge con la prima volta, Se non gli è rotto il cerchio d’alcun canto: In questa altezza, che tutta è disciolta Nell’ aer vivo, tal moto percote E fa sonar la selva, perch ’è folto.”[649]
The whole body of the air, everywhere in the world, is turning with the First Revolution (the Primum Mobile), wherever it is not interrupted by any obstruction (of hills etc.); and as at this height the Mountain is altogether free and open to the pure air, this motion strikes the thick forest and makes it murmur.[650]
From this region of pure air, Dante rises with Beatrice through the sphere of Fire, into which already in a dream he had been rapt, on the first night in Purgatory, by the Eagle with golden feathers, when the burning heat of the dream-fire roused him from his sleep.[651] Now he feels no heat, but is amazed at the vast extent of light, greater than any river or lake ever seen on earth, and at the same moment he begins to hear the music of the eternal spheres,[652] for he is approaching the heaven of the moon.
In each one he hears it until the seventh is reached, but here, in pity for his mortal senses, which are not yet strong enough to bear so much divine beauty, not only does Beatrice forbear to smile, but the sweet symphonies of heaven are silent.[653]
Did Dante then, in spite of Aristotle, believe in the music of the spheres? Perhaps the fact that only the Commedia, of all his works, makes mention of it indicates that he only thought of it as a poetical fiction, an allegory? Yet it was fully believed in by many in his day, although opinions varied greatly as to what note each planet sang. The favourite idea among Greek and Latin writers seems to have been that the notes made up a musical scale, the lowest sphere sounding forth the lowest note, and the star sphere its octave; but others thought that only the seven planets took part in the harmony, corresponding with the seven strings of the lyre: the moon being at the shortest distance from Earth, was the shortest string and gave the highest note, Saturn was the longest and gave the deepest.
Our own Milton, when he prays, “Ring out, ye crystal spheres,” bids the Primum Mobile join in, as well as the star sphere:
“And with your nine-fold harmony Make up full concert to the angelic symphony.”[654]