1913 is a critical limitation imo - the one constant in language is change, and there's been so much change in English over the past century that a dictionary so old is of limited value. Unless one has strong prescriptivist tendencies, and treats "the dictionary" as an arbiter of language instead of merely a chronicler thereof. That's why I am pleased my public library maintains its OED subscription. That effectively makes the most comprehensive English dictionary "public domain" for me, offering the best of both worlds - detailed definitions of variants and etymologies and (more or less) up-to-date vocabulary and usage notations