पृथिवी वाव गौतमाग्निस्तस्याः संव-त्सर एव समिदाकाशो धूमो रात्रिरर्चि-र्दिशोऽङ्गारा अवान्तरदिशो विस्फुलिङ्गाः ॥
In plain words
The earth itself is the fire taught to Gautama. The year is its fuel, space its smoke, night its flame, the cardinal directions its glowing coals, and the intermediate directions its flying sparks.
Close to the Sanskrit
The earth indeed is the fire of Gautama, of that the year alone is the fuel, space is the smoke, night is the flame, the directions are the embers, the intermediate directions are the sparks.