He was general editor from 1910 to 1914 for the long-projected historical
Dictionary of the Irish Language, the first
fascicle of which was published by the
Royal Irish Academy in 1913. His articles were of enduring influence, and published in
Revue Celtique and
Zeitschrift für Celtische Philologie, and his own journal,
Norsk Tidsskrift for Sprogvidenskap which he founded in 1928. His
Bidrag til det Norske Sprogs historie i Irland (1915) and
Les présents indo-européens à nasale infixée en celtique (1924), are two of his larger works. He is also known for his writings on the history of the
Isle of Man, and for securing support and recognition for the Manx historian
John Kneen. He made pioneering sound recordings of the
Manx language, at a time when few fluent native speakers survived. He theorised a North Italian or
Etruscan origin for the
runes. This was, however, partly based on an artefact known now to have been faked. ==Notes==