सिद्धान्तशिरोमणि: गणिताध्याय (भास्कराचार्य - ग्रहगणित, मध्यमाधिकार व स्पष्टाधिकार सटीक)

80 length of a Solar month will be 29-20-40. This will be so when the average daily motion during the course of a month is 61-20-30. Verse 7. A mention of the years past and future that had and will have Kshayamāsās. A Kshayamāsa occured in the Saka year 974 and will occur in the years 1115, 1256, 1378. Thus generally it occurs once in 141 years or even 19 years. Comm. We have seen before that according to the convergents given above a Kshayamāsa generally occurs in 19 years or 122 years or 141 years. In the course of the commentary Bhāskara says "19 years before or after" so that 141-19=122 years was also meant by him. He gives how in the course of 141 years or 19 years the Suddhi at the be- ginning of the year happens to be approximately 21 days. In this behalf, he invokes his formulation of the Adhika- māsās in the verse 6 under Pratyabdasuddhi. As per that formula the number of Adhikamāsās in 19 years will be 7-13-37-30 taken by Bhāskara as 7-13-40. In other words the Suddhi increases by 13 ghatis and 38 palas from what it was 19 years ago; thus practically the value of the Suddhi recurs in periods of 19 years which means that if a Kshayamāsa occurred this year, there is a likelihood of its recurrence after nineteen years. Of course the recurrence would not be certain because there is an excess of 13 ghatis Suddhi which might preclude its occurrence. Similarly in 122 years and 141 years the numbers of Adhikamāsās would be respectively 45 minus 7-15 ghatis and 52 plus 6 ghatis. 22 palas and 30 Vipalas, the latter being taken by Bhaskara to be 52 Adhikamāsās plus 6 ghatis and 20 palas. Thus Kshayamāsas are more and still more likely to recur in intervals of 122 years and 141 years respectively, the Suddhis at the beginning of the year almost recurring and assuming the original value of 21 days for a Kshayamāsa to occur.