Bundahishn 25

On matters of religion it says in revelation thus 'The creatures of the world were created by me complete in three hundred and sixty-five days,' that is, the six periods of the Gâhanbârs which are completed in a year.

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 Tir, to the season of Mêdiyârêm, which is the auspicious day Vâhrâm of the month Din '—the shortest day-the night increases; and from the season of Mêdiyârêm to the season of Mêdôk-shêm the night decreases and the day increases.

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.

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.

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.

As from the auspicious day Aûharmazd of the month Fravardin 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 the winter of five months.

The priest fulfils the regulation (vakar) about a corpse and other things, by this calculation as to summer and winter.

In those seven months of summer the periods (gâs) of the days and nights are five-since one celebrates the Rapitvin-namely, the period of daybreak is Hâvan, the period of midday is Rapitvin, the period of afternoon is Aûzêrîn, when the appearance of the stars has come into the sky until midnight is the period of Albisrûtêm, from midnight until the stars become imperceptible is the period of Aushahin %.

In winter are four periods, for from daybreak till Aûzêrin 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 Vôrugarst are; the original dwelling of summer, too, is in the south, where the regions Fradadafsh and Vidadafsh are; on the day Aûharmazd of the auspicious month Avân the winter acquires strength and enters into the world, and the spirit of Rapitvin goes from above-ground to below-ground, where the spring (khân) of waters is, and diffuses warmth and moisture in the water, and so many roots of trees do not wither with cold and drought.

And on the auspicious day Åtarô of the month Din the winter arrives, with much cold, at Airân-veg; 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 Din, and it forms an indication that winter has come.

In those five months the water of springs and conduits is all warm, for Rapitvin keeps warmth and moisture there, and one does not celebrate the period of Rapitvin.

As the day Aûharmazd of the month Fravarɗîn advances it diminishes the strength which winter possesses, and summer comes in from its own original dwelling, and receives strength and dominion.

Rapitvin comes up from below-ground, and ripens the fruit of the trees; on this account the water of springs is cold in summer', for Rapitvin is not there; and those seven months one celebrates the Rapitvin, and summer advances through the whole earth.

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.

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.

In the middle localities the cold of winter and heat of summer both come on vehemently.

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 twentynine, 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.

Whoever keeps the year by the revolution of the moon mingles summer with winter and winter with summer.

This, too, it says, that the auspicious month Fravardin, the month Ardavahist, and the month Horvadad are spring; the month Tir, the month Amerôdad, and the month Shatvairô are summer; the month Mitrô, the month Âvân, and the month Âtarô are autumn; the month Din, the month Vohuman, and the month Spendarmad are winter.

And the sun comes from the sign (khurdak) 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.

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.