Agni Purana (Jyotisha Selections) · by Vyasa
Chapter 1 · Muhurta: Marriage, Home, Farming
ज्योतिःशास्त्रम्
सप्तमे पञ्चविंशः स्यात्खण्डशः पिण्डकाद्भवेत् ।कर्कटादौ हरेद्राशिमृतुवेदत्रयैः क्रमात् ॥ १४ ॥
In the full Agni Purana this is chapter 122, verse 14.
For the 7th it is twenty-five. Each part comes from the pinda (total figure). From Cancer, the signs take 6, 4 and 3 in order.
Simple meaning: The seventh is twenty-five. From Cancer the three signs take six, four and three.
तुलादौ प्रातिलोम्येन त्रयो वेदरसाः क्रमात् ।
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.