Narada Purana (Jyotisha Selections) · by Vyasa
Chapter 5 · Portents, Comets
ग्रहचारः केतवश्च
रौद्रेन्दुसार्पपित्र्येषु ज्ञेया मिश्राह्वया गतिः ।भाग्यार्यमेज्यादितिषु संक्षिप्ता गतिरुच्यते ॥ ४५ ॥
In the full Narada Purana (Purva Bhaga) this is chapter 56, verse 45.
In Ardra, Mrigashira, Ashlesha and Magha, know the path called mixed. In Purva Phalguni, Uttara Phalguni, Pushya and Punarvasu, the path is called short.
Simple meaning: Mercury's path is mixed in some stars and short in others.
गतिस्तीक्ष्णाजचरणाहिर्बुध्न्यभाश्रिभेषुया ।
Mercury's path is sharp in some stars and Yogantika in others.
घोरा गतिर्हरित्वाष्ट्रवसुवारुणभेषु च ।
Mercury's path is fierce in some stars and bad in others.
प्राकृताद्यासु गतिषु ह्युदितोऽस्तमितोपिवा ।
In each path, Mercury stays hidden for as many days as it was seen.