The Mauryan Polity c5.s2.t9.3

c5.s2.t9.3

The Chapter 20 of Book II of the *Arthaśāstra* gives us enough details to arrive at a satisfactory calculation. The term *yuga* is used in the sense of a period of five years which is, in other words, the Vedic quinquennial cycle.² That Kauṭalya is indebted to the *Vedāṅga Jyotiṣa* is evident. Among the regal studies mentioned are the four Vedas and six Aṅgas of which Jyotiṣa or astronomy is one.³ Kauṭalya says that the equinox is in the months of *caitra* and *āśvayuja*⁴ (vernal and autumnal equinox), and it increases or diminishes by three muhūrtas once in every six months. This means that the length of the day and night (ahorātra) may vary to the maximum extent of three muhūrtas or one and a half muhūrtas (72 minutes) before 6 A.M. and one and a half muhūrtas after 6 P.M. (local time). Says Swamikannu Pillai: "It will be seen from Table XIII appended to my Indian Chronology that this condition will be satisfied only above the thirtieth parallel of latitude where a maximum variation of about 70 minutes is attained in the moment of sunrise."¹