Sentence:  ...and there, after due prayers to the gods who dwell in ether <WSD>supernal</WSD>, had taken solemn counsel whereby they might, if so be it might be, bring once more into honour among mortal men the winged speech of the seadivided Gael. 
Meaning of the word marked with <WSD> tags:  Pertaining to heaven or to the sky; celestial.