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

76
literature and it is not clear whether observance of this
Kshayamāsa was defunct for some centuries in between.
3. We shall now proceed to see how there occur two
Adhikamāsas on either side of a Kshayamāsa. A simple
argument is as follows. The convergents cited above
namely 19/7 or 122/45 or 141/52 signify that either 7 or 45 or 52
Adhikamāsās are to occur in the course of 19 or 122 or 141
Solar years normally. But when the S'uddhi happens to
be 21 days at the beginning of the Solar year, it so happens
that the S'uddhi goes on increasing for the first five
months because the Sun is in his apogee when his
longitude is 78°, and his motion being slow for three
months when he is on either side of his apogee, the
Moon gains over him in shorter intervals of time and as
a consequence the lunations are of shorter duration. This
means that the S'uddhi goes on increasing during those
months and rapidly increases from its value 21 at the
beginning to 30 by about Bhādrapada month. Under
these circumstances, a Samkramaṇa occurs generally just
before the beginning of Bhādrapada. The next Samkra-
maṇa happens just a little after the lapse of Bhādrapada,
so that the month of Bhādrapada goes without a Samkra-
maṇa and as a consequence, it becomes an Adhikamāsa.
Thus far it is alright that an Adhikamāsa has occured
as per the meaning of the convergents. But when the
Bhādrapada thus becomes an Adhikamāsa, the subsequent
months from Kārtica to Mārgasira, being of longer duration
than the corresponding Solar months, the Sun having a
quicker motion on either side of his perigee, there is every
likelihood of a Solar month being contained between two
conjunctions or New Moon days. In other words two
Samkramaṇas occur either in Kārtica or Mārgasira or
Pausha. This means that as per the convention for the
occurence of a Khayamāsa, one of the aforesaid lunations
must become a Kshayamāsa. Thus the Adhikamāsa which