Note 31 — TRUNK-WITHOUT-HEAD.
Reading edition
That means “It was well for yourself it was so.” This old Elizabethan idiom is of frequent occurrence in Connacht English, having with many other Elizabethanisms, either filtered its way across the island from the Pale, or else been picked up by the people from the English peasantry with whom they have to associate when they go over to England to reap the harvest.