Śatapatha Brāhmaṇa ("of a hundred paths") 8.2.3.4

8.2.3.4

athāpasyā upadadhāti | etadvai devā abruvaṃścetayadhvamiti citimicateti vāva tadabruvaṃste cetayamānā vṛṣṭimeva citimapaśyaṃstāmasminnadadhustathaivāsminnayametaddadhāti

He then lays down the Apasyâ (bricks). For the gods, at that time, spake, 'Meditate ye!' whereby, doubtless, they meant to say, 'Seek ye a layer!' Whilst meditating, they saw even that layer, rain: they put it into that (fire-altar) and in like manner does he now put it therein.