Agni Purana (Jyotisha Selections) · by Vyasa
Chapter 1 · Muhurta: Marriage, Home, Farming
ज्योतिःशास्त्रम्
तुलादौ प्रातिलोम्येन त्रयो वेदरसाः क्रमात् ।मकरादौ दीयते(न्ते(?)) च रसवेदत्रयः क्रमात् ॥
In the full Agni Purana this is chapter 122, verse 15.
From Libra, in reverse: 3, 4 and 6 in order. From Capricorn, 6, 4 and 3 are given in order. (Our text is unclear here: the ending of the verb 'given'.)
Simple meaning: From Libra the figures run three, four, six. From Capricorn they run six, four, three.
हन्याल्लिप्तां गतागामिपिण्डसंख्याफलान्तरैः ।
Find the in-between value: multiply the minutes by the step difference and divide by sixty.
द्वितीयोच्चरिते वर्गे वैपरीत्यमिति स्थितिः ।
In the second group the rule is reversed. Then the moon day is doubled and a sixth taken off.
रविकर्मविपरीता तिथिनाडीसमायुता ।
Apply the Sun's correction in reverse and add the moon day ghatikas. If the minus is too big, see the next verse.