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The Mauryan Polity c5.s2.t9: Astronomical Data

The Mauryan Polity c5.s2.t9

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English

Astronomical Data

c5.s2.t9.1

In fixing the date of the composition of the *Arthaśāstra* the astronomical evidence comes in very handy. Two Indian scholars have independently examined this question and the results of their investigations have been curiously identical. These are the late Rājarāja Varma of Trivandrum and L. D. Swamikannu Pillai.¹

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¹ See *Some Aspects of An. Ind. Polity*, pp. 123-127; 153-154. See also Jacobi's observations in *Indian Antiquary*, Vol. 47, pp. 157-161 and pp. 187-195.

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

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² Cp. *Vāyu Purāṇa*, ch. 31.28: 50.183, etc. I have discussed this at some length in my forthcoming paper on *Some Aspects of Vāyu Purāṇa*.

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³ Bk. I, ch. iii.

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⁴ Bk. II, ch. xx.

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¹ *Some Aspects of An. Ind. Polity*, p. 124. ² Bk. II, ch. xx. ³ Ibid. ⁴ *Some Aspects of An. Ind. Polity*, p. 123. ⁵ Bk. II, ch. xx.

c5.s2.t9.8

Another statement that 'no shadow is cast at noon in the month of Āṣāḍha'² affords a positive clue that the author is a native of the tropics.

c5.s2.t9.9

Again according to the Arthaśāstra the solar month consists of 30½ days whereas the lunar month consists of 29½ days. Thus the lunar year is said to consist of 354 days and the solar year 366 days. In the five-year cycle the difference between the solar, and the lunar, years is sixty days. These are characterised as adhimāsas.³ Thus "the position of the solstices as well as the occurrence of intercalary months and other items of lunisolar calendar in the Arthaśāstra, are in agreement with the conclusions of the Vedāṅga Jyotiṣa".⁴

c5.s2.t9.10

The Arthaśāstra knows of the sexagesimal system when it says two nālikas equal one muhūrta⁵

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15 muhūrtas equal a day, or a night and 30 *muhūrtas* equal one day and a night or 60 *nāḷikās*.

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According to Dr. Burgess the sexagesimal system of Hindu astronomy was borrowed from the Greeks.¹ This implies that the *Jyotiṣa Vedāṅga* which has become a popular work in pre-Kauṭalīyan days (4th century B.C.) must have been written after India's contact with the Greeks. It is an untenable position. *Jyotiṣa Vedāṅga* is an ancient production belonging at least to the later half of the Vedic Period. It holds the field as a valuable piece of scientific composition. If Greece could develop in the direction of sexagesimal system, could not India develop also in that line? Further that the sexagesimal system is exclusively Greek in origin has not been proved. It is just possible that India developed this system on independent lines.

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¹ J.R.A.S., 1893, p. 753.

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