#### Book 5: Chapter 21

## References

- ↑ As the sun never remains at a fixed position according to the ancients and is constantly changing its course, turning more and more either towards the north or towards the south, days and nights are of equal duration, strictly speaking, only on two days in a year, viz., on the vernal and autumnal equinoxes. But the disparity in their length is very negligible during these two parts of the year, covering a total period of nearly two months, as it never exceeds 24 minutes. It is therefore that days and nights are spoken of as equal in length during this period. Similarly the length of days gradually increases and the length of nights is proportionately reduced only when the sun traverses the signs of Vrsabha and Mithuna; while during the other three months, viz., when the sun traverses the signs of Karkata, Simha and Kenya, the order is reversed, that is to say, the length of nights gradually increases and that of days diminishes. Days, however, nonetheless continue to be longer than nights till the sun takes to the southward course--- vide passage above. It is in this light that the statement in the latter part of passage above should be interpreted. And the statement made in passage above should also be construed likewise. Even so the monthly rate of fall in the duration of nights during the five months of the sun's northward course and in the length of days during the corresponding months of its southward course is not uniform every month; sometimes it exceeds 24 minutes, while at other times it is less than 24 minutes. 24 minutes should, therefore, be taken to be the average rate.
- ↑ By adding together half the diameter (fifty thousand Yojanas) of Jambudwipas-which lies at the centre of the lotus-like terrestrial globe----and the width of the five other circular Dwipas surrounding it, each of which is twice as large as the one preceding it, as well as of the six belts of oceans encircling the six Dwipas, each of which is equal in extent to the Dwipa enclosed by it, and joining to the total width of these six Dwipas and the same number of oceans surrounding them half the width of the seventh and largest Dwipa (Puskaradwipa) at the centre of which the mountain-belt called Manasottara is placed. the figure of one crore, fifty-seven lakh and fifty thousand Yojanas is arrived. This represents the radius of the circle described by the revolution of the sun's chariot on the top of the Manasottara mountain with Mount Meru, standing at the core of Jambudwipa, as its centre. The double of this number or 3 crore and fifteen lakh Yojanas represents the extent of its diameter. According to the established rules of geometry the extent of the circumference of a circle is 3 1/7 times as much as its diameter. Multiplying the length of the diameter as calculated above by 3 1/7 the figure comes to nine crore and ninety lakh Yojanas. This, however, does not tally with the figure cited in the text, which is 39,00,000 less. A learned commentator, however, points out that, really speaking, the distance from the centre of Mount Meru to the orb of the sun itself should be reckoned as +he radius of the circle and this has been ascertained from other authoritative sources to be in the neighbourhood of one crore and fifty-one lakh Yojanas only. Thus calculated, the diameter of the circle works out at the figure of three crore and two lakh Yojanas approximately. And by multiplying this figure by 3 1/7 the result arrived at exactly corresponds to the figure quoted in the text.