Jain Journal 1984 01

Author(s): Jain Bhawan Publication
Publisher: Jain Bhawan Publication

Page 16

JANUARY, 1984
it these days. This also implies that north-south stretch D1 of solar mandalas in Lavanasamudra starts from 6°.9 North, the southern limit of D1, verisimilarly coinciding with the southern limit of ancient India including modern 'Sri Lanka'. Besides, it may be confirmed from Nautical Almanac that declination of Sun decreases from its maximum value on Summer solstice day to about 7° North in a span of about 75 days and to about 8°.5 North (southern limit of modern India)8 in a span of about 70 days. Thus it seems convincing that verisimilarly the southward journey of Sun was measured in Yojanas starting from a station on earth where the noon-shadow-length of gnomon was zero on the Summer solstice day i.e. starting from a station situated in the neighbourhood of terrestrial latitude of 23°.5 North (which is incidently very close to the latitude of Ujjain, a renowned seat of ancient Indian culture) upto the station situated at about the extreme southern limit of ancient India where again the noon-shadow-length was observed to be zero after 65 days since Summer solstice day. This also testifies their technique of measuring celestial angular distances in terms of corresponding distances projected over the surface of the earth.10
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However, it is worthy of note that a small discrepency in reckoning the number of solar mandalas in Jambudvipa to be 65 instead of 70 or 75 as ought to have been as shown above, was due to obstacles in measuring the moon-shadow-length. Several errable factors like the ending of shadow in penumbra, slow velocity of shadow length near the meridian transit of Sun and slight inclination of gnomon etc. are pertaining thereto.11 Besides it cannot be claimed with certainty as to which place on the sea coast might have been mistaken for the southern extremity of their land which was supposed to be a circular land mass surrounded by the ocean ring (Lavana samudra). (Incidently, in 65 days since Summer solstice day, Sun's declination becomes about 10° North. This might refer to some place in modern Kerala state.) Keeping in view these very factors, it is contemplable that Jainas had actually measured in Yojanas, total change in Sun's declination (or variation in NPD as Jainas understood) in 65 solar mandalas (Sun's diurnal circles) in Sun's southern journey starting from the innermost mandala
• See Bartholomew, J. (1960), The Graphic Atlas, 11th Ed., p. 53.
• See Lahiri, N. C. (1975), Indian Ephemeris, pp. 18-24. See also Indian Nautical Alumanac.
10 See our paper 'Role of Pre-Aryabhata Jaina School of Astronomy in the Development of Siddhantic Astronomy', paper presented at Celebration of the 1500th birth anniversary of Aryabhata I (Nov. 2-4, 1976). INSA, New Delhi. IJHS, Vol. 12, No. 2, pp. 106-113.
11 Smith, D.E. (1958), History of Mathematics, Vol. 2, p. 671 (New York).