Narada Purana (Jyotisha Selections) · by Vyasa
Chapter 5 · Portents, Comets
ग्रहचारः केतवश्च
प्राकृतायां गतः सौम्यः क्षेमारोग्यसुभिक्षकृत् ।मिश्रसंक्षितयोर्मध्ये फलदोऽन्यासु वृष्टिदः ॥ ५० ॥
In the full Narada Purana (Purva Bhaga) this is chapter 56, verse 50.
Mercury on the natural path brings welfare, health and plenty. In the mixed and short paths it gives middling results. In the other paths it gives rain.
Simple meaning: Mercury's natural path brings welfare and health. The mixed and short paths are middling.
वैशाखे श्रावणे पौषे आषाढेऽभ्युदितो बुधः ।
Mercury rising in some months brings bad results to the world. In other months it is good.
इषोर्जमासयोः शस्त्रदुर्भिक्षाग्निभयप्रदः ।
Mercury rising in Ashvina or Kartika brings weapon, famine and fire fear. A silver-white Mercury is best.
कार्तिको मार्गशीर्षश्च नृणां दुष्टफलप्रदः ।
Kartika and Margashirsha are bad for people. Pausha and Magha are good. Phalguna and Chaitra are middling.