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_). ------------------------------------------------------------------------