(6) And twice in every year the day and night are equal, for on the original attack, when it (the sun) went forth from its first degree (khûrdak), the day and night were equal, it was the season of spring; when it arrives at the first degree of Kalakang (Cancer) the time of day is greatest, it is the beginning of summer; when it arrives at the sign (khûrdak) Tarâgûk (Libra) the day and night are equal, it is the beginning of autumn; when it arrives at the sign Vahîk (Capricorn) the night is a maximum, it is the beginning of winter; and when it arrives at Varak (Aries) the night and day have again become equal, as when it went forth from Varak.

(2) It is always necessary first to count the day and afterwards the night, for first the day goes off, and then the night comes on. And from the season (gâs) of Mêdôk-shêm, which is the auspicious day Khûr of the month Tîr, to the season of Mêdîyârêm, which is the auspicious day Vâhrâm of the month Dîn—the shortest day—the night increases; and from the season of Mêdîyârêm to the season of Mêdôk-shêm the night decreases and the day increases. 4. The summer day is as much as two of the shortest winter days, and the winter night is as much as two of the shortest summer nights. 5. The summer day is twelve Hâsars, the night six Hâsars; the winter night is twelve Hâsars, the day six; a Hâsar being a measure of time and, in like manner, of land. 6. In the season of Hamêspamadâyêm, that is, the five supplementary days at the end of the month Spendarmad, the day and night are again equal. 7. As from the auspicious day Aûharmazd of the month Fravardîn to the auspicious day Anîrân of the month Mitrô is the summer of seven months, so from the auspicious day Aûharmazd of the month Âvân to the auspicious month Spendarmad, on to the end of the five supplementary days, is winter of five months. 8. The priest fulfils the regulation (vakar) about a corpse and other things, by this calculation as to summer and winter. 9. In those seven months of summer the periods (gâs) of the days and nights are five—since one celebrates the Rapîtvîn—namely, the period of daybreak is Hâvan, the period of midday is Rapîtvîn, the period of afternoon is Aûzêrîn, when the appearance of the stars has come into the sky until midnight is the period of Aîbisrûtêm, from midnight until the stars become imperceptible is the period of Aûshahîn. 10. In winter are four periods, for from daybreak till Aûshahîn is all Hâvan, and the rest as I have said; and the reason of it is this, that the appearance of winter is in the direction of the north, where the regions Vôrûbarst and Vôrûgarst are; the original dwelling of summer, too, is in the south, where the regions Fradadafsh and Vîdadafsh are; on the day Aûharmazd of the auspicious month Âvân the winter acquires strength and enters into the world, and the spirit of Rapîtvîn goes from above-ground to below-ground, where the spring (khânî) of waters is, and diffuses warmth and moisture in the water, and so many roots of trees do not wither with cold and drought. 11. And on the auspicious day Âtarô of the month Dîn the winter arrives, with much cold, at Aîrân-vêg; and until the end, in the auspicious month Spendarmad, winter advances through the whole world; on this account they kindle a fire everywhere on the day Âtarô of the month Dîn, and it forms an indication that winter has come. 12. In those five months the water of springs and conduits is all warm, for Rapîtvîn keeps warmth and moisture there, and one does not celebrate the period of Rapîtvîn. 13. As the day Aûharmazd of the month Fravardîn advances it diminishes the strength which winter possesses, and summer comes in from its own original dwelling, and receives strength and dominion. 14. Rapîtvîn comes up from below-ground, and ripens the fruit of the trees; on this account the water of springs is cold in summer, for Rapîtvîn is not there; and those seven months one celebrates the Rapîtvîn, and summer advances through the whole earth. 15. And yet in the direction of Hindûstân, there where the original dwelling of summer is nearer, it is always neither cold nor hot; for in the season which is the dominion of summer, the rain always dispels most of the heat, and it does not become perceptible; in the winter rain does not fall, and the cold does not become very perceptible. 16. In the northern direction, where the preparation of winter is, it is always cold; for in the summer mostly, on account of the more oppressive winter there, it is not possible so to dispel the cold that one might make it quite warm. 17. In the middle localities the cold of winter and heat of summer both come on vehemently. 18. Again, the year dependent on the revolving moon is not equal to the computed year on this account, for the moon returns one time in twenty-nine, and one time in thirty days, and there are four hours (zamân) more than such a one of its years; as it says, that every one deceives where they speak about the moon (or month), except when they say that it comes twice in sixty days. 19. Whoever keeps the year by the revolution of the moon mingles summer with winter and winter with summer. 20. This, too, it says, that the auspicious month Fravardîn, the month Ardavahist, and the month Horvadad are spring; the month Tîr, the month Amerôdad, and the month Shatvaîrô are summer; the month Mitrô, the month Âvân, and the month Âtarô are autumn; the month Dîn, the month Vohûman, and the month Spendarmad are winter. 21. And the sun comes from the sign (khûrdak) of Aries, into which it proceeded in the beginning, back to that same place in three hundred and sixty-five days and six short times (hours), which are one year. 22. As every three months it (the sun) advances through three constellations, more or less, the moon comes, in a hundred and eighty days, back to the place out of which it travelled in the beginning.

(20) For the motion of the sun from solstice to solstice is completed in six months - in the course of which, at one time the leaves fall, and at another plants bud and seeds come to maturity. And they say that the embryo is perfected exactly in the sixth month, that is, in one hundred and eighty days in addition to the two and a half, as Polybus the physician relates in his book On the Eighth Month, and Aristotle the philosopher in his book On Nature. Hence the Pythagoreans, as I think, reckon six the perfect number, from the creation of the world, according to the prophet, and call it Meseuthys and Marriage, from its being the middle of the even numbers, that is, of ten and two. For it is manifestly at an equal distance from both.

(74) And the sun and the stars bring in all the years exactly, so that they do not advance or delay their position by a single day unto eternity; but complete the years with perfect justice in 364 days.

(2) And God appointed the sun4 to be a great sign on the earth for days and for sabbaths and for months and for feasts and for years and for sabbaths of years and for jubilees and for all seasons of the years.

(71) Thus on the fourth day, in the anxious birth or geniture of this world, in the middle point or centre of this world, the SUN is sprung up, and stands still in its eternal, corporeal place; for it cannot rise up in one place, and set in another.