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.