By the way, how comes burden to be used in the sense of "chorus or refrain?" I believe we have the authority of Shakspeare for so doing.
"Foot it featly here and there
And let the rest the burden bear?"
Is it the bourdon, or big drone? Certainly the chorus could not "bear a burden," in the sense of hard work, even before the time of Hullah.
J. P. Orde.
In Chambers' Scottish Songs, Edinburgh, 1829, p. 273. is a piece beginning—
"And was you e'er in Crail toun?
Igo and ago;
And saw ye there clerk Fishington?
Sing irom, igon, ago."