Khandogya-Upanishad: Fifth Prapathaka, Sixth Khanda

1. “The altar is the earth, O Gautama; its fuel is the year itself, the smoke the ether, the light the night, the coals the quarters, the sparks the intermediate quarters.

2. “On that altar the Devas (prânas) offer rain. From that oblation rises food (corn, &c.)