3When the sun has entered the sign of Aries, and run through about an eighth part of it, it is the vernal equinox. When he has arrived at the tail of Taurus and the Pleiades, for which the fore part of the Bull is conspicuous, he has advanced in the heavens more than half his course towards the north. From Taurus, he enters into Gemini, at the time when the Pleiades rise, and being more over the earth increases the length of the days. From Gemini entering into Cancer, which occupies the smallest space in the heavens, and coming to the eighth division of it he determines the solstice, and moving forward arrives at the head and breast of Leo, which are parts properly within the division assigned to Cancer.
2From the breast of Leo and the boundaries of Cancer, the sun moving through the other parts of Leo, has by that time diminished the length of the day, as well as of his circuit, and resumes the equal motion he had when in Gemini. Hence from Leo passing to Virgo and proceeding to the indented part of her garment, he contracts his circuit, which is now equal to that which it had in Taurus. Proceeding then from Virgo through the indentation which includes the beginning of Libra, in the eighth part of that sign, the autumnal equinox is completed; the circuit being then equal to that in the sign Aries.
3When the sun enters into Scorpio at the setting of the Pleiades, he diminishes, in passing to the southern parts, the length of the days; and from Scorpio passing to a point near the thighs of Sagittarius, he makes a shorter diurnal circuit. Then beginning from the thighs of Sagittarius, which are in Capricornus, at the eighth part of the latter he makes the shortest course in the heavens. This time from the shortness of the days, is called Bruma (winter) and the days Brumales. From Capricornus passing into Aquarius, the length of the days is increased to that of those when he was in Sagittarius. From Aquarius he passes into Pisces at the time that the west wind blows; and his course is equal to that he made in Scorpio. Thus the sun travelling through these signs at stated times, increases and diminishes the duration of the days and hours. I shall now treat of the other constellations on the right and left of the zodiac, as well those on the south as on the north side of the heavens.