thus discoursed on the subject.

"'"Vyasa said, 'Only Brahma, which is without beginning and without end,
unborn, blazing with effulgence, above decay, immutable, indestructible,
inconceivable, and transcending knowledge, exists before the
Creation.[872] The Rishis, measuring time, have named particular portions
by particular names. Five and ten winks of the eye make what is called a
Kashtha. Thirty Kashthas would make what is called a Kala. Thirty Kalas,
with the tenth part of a Kala added, make what is known as a Muhurta.
Thirty Muhurtas make up one day and night. Thirty days and nights are
called a month, and twelve months are called a year. Persons conversant
with mathematical science say that a year is made up of two ayanas
(dependent on sun's motion), viz., the northern and the southern. The sun
makes the day and the night for the world of man. The night is for the
sleep of all living creatures, and the day is for the doing of action. A
month of human beings is equal to a day and night of the Pitris. That
division (as regards the Pitris) consists in this: the lighted fortnight
(of men) is their day which is for the doing of acts; and the dark
fortnight is their night for sleep. A year (of human beings) is equal to
a day and night of the gods. The division (as regards the gods) consists
in this: the half year for which the sun travels from the vernal to the
autumnal equinox is the day of the deities, and the half year for which
the sun travels from the latter to the former is their night. Computing
by the days and nights of human beings about which I have told thee, I
shall speak of the day and night of Brahman and his years also. I shall,
in their order, tell thee the number of years, that are (thus) for
different purposes computed differently in respect of the Krita, the
Treta, the Dwapara, and the Kali yugas. Four thousand years (of the
deities) is the duration of the first or Krita age. The morning of that
epoch consists of four hundred years and its evening is of four hundred
years. (The total duration, therefore, of the Krita yuga is four thousand
and eight hundred years of the deities). As regards the other yugas, the
duration of each gradually decreases by a quarter in respect of both the
substantive period with the conjoining portion and the conjoining portion
itself. (Thus the duration of the Treta is three thousand years and its
morning extends for three hundred years and its evening for three
hundred).