Chandogya Upanishad
Prapathaka III, Khanda 15
The chest which has the sky for its circumference and the earth for its bottom, does not decay, for the quarters are its sides, and heaven its lid above. That chest is a treasury, and all things are within it.
Its eastern quarter is called Guhû, its southern Sahamânâ, its western Râgñî, its northern Subhûtâ . The child of those quarters is Vâyu, the air, and he who knows that the air is indeed the child of the quarters, never weeps for his sons. 'I know the wind to be the child of the quarters, may I never weep for my sons.'
'I turn to the imperishable chest with such and such and such .' 'I turn to the Prâna (life) with such and such and such.' 'I turn to Bhûh with such and such and such.' 'I turn to Bhuvah with such and such and such.' 'I turn to Svah with such and such and such.'