 His work on Nowell included the discovery in 1934, in Nowell's transcription, of the poem "Seasons for Fasting".He translated from the writings of Tomás Ó Criomhthain, his Irish language teacher on the Blasket Islands, and wrote a memoir, "The Western Island; Or, the Great Blasket" (1944), illustrated by his wife Ida.The essay collection "The Irish Tradition" (1947) is often cited, and was reprinted in 1994; it includes "Ireland and Medieval Europe", his "John Rhŷs Memorial Lecture" from 1927.