From the Wikipedia page 
Dates 24 February 1877-27 June 1952.
His 1903 doctoral thesis on the history of Thessaly traces the history of the country with particular attention to the times between 600 and 300 BC. Unfortunately, only Chapter V and two appendices were published, and the bulk of his dissertation, according to the University of Philadelphia, is currently lost. His Old Persian: Grammar, Texts, Lexicon is one of the seminal works on the subject.
He published William Romaine Newbold's book.