then biorn sang this song : o ground of the golden strings , might we but gain it to make this days wearing of all days the longest that ever yet hung twixt earths woodland and heaven -- yea , whiles yet i tarried the hours in their waning -- for , o fir of the worm that about the arm windeth , this night amongst all nights , tis i and no other must turn me to grief now , and drink out the grave-ales of the joys of our life-days , full often a-dying .