yamas catvaras catvaro
martyanam ahani ubhe
suklah krsnas ca manada
yamah—three hours; catvarah—four; catvarah—and four; martyanam—of the human beings; ahani—duration of day; ubhe—both day and night; paksah—fortnight; panca-dasa—fifteen; ahani—days; suklah—white; krsnah—black; ca—also; manada—measured.
It is calculated that there are four praharas, which are also called yamas, in the day and four in the night of the human being. Similarly, fifteen days and nights are a fortnight, and there are two fortnights, white and black, in a month.
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