"One dowle that's in my plume."
For 'dowle' I read with confidence down, believing it to be a printer's error for dowlne, a mode of spelling down:
"There lies a dowlney feather, which stirs not.
Did he suspire, that light and weightless dowlne
Perforce must move."
2 Hen. IV. iv. 2, fol.
Singer refers to dictionaries, etc., of the 17th century for the use of dowle; but they all probably found it only in this place.