Śatapatha Brāhmaṇa ("of a hundred paths") 8.7.3.9

8.7.3.9

atha vikarṇīṃ ca svayamātṛṇāṃ copadadhāti | vāyurvai vikarṇī dyauruttamā svayamātṛṇā vāyuṃ ca taddivaṃ copadadhātyuttame upadadhātyuttame hi vāyuśca dyauśca saṃspṛṣṭe saṃspṛṣṭe hi vāyuśca dyauśca pūrvāṃ vikarṇīmupadadhātyarvācīnaṃ taddivo vāyuṃ dadhāti tasmādeṣo 'rvācīnameva vātaḥ pavate

He then lays down the Vikarnî and Svayamâtrinnâ (bricks),--the Vikarnî is Vâyu (the wind), and the last naturally-perforated one is the sky: he thus sets up both the wind and the sky. He lays them down as the last (highest), for wind and sky are the highest; and close together, for wind and sky are close together. The Vikarnî he lays down first: he thereby places the wind on this side of the sky; whence that wind blows only on this side (thereof).