Works published in 1926 would have had to renew their copyright in either 1953 or 1954, i.e. at least 27 years after it was first published / registered but not later than 31 December(31 December) in the 28th year. As it was not renewed, it entered the public domain on 1 January 1955(1 January 1955).
The translator died after 1950, so this work is also in the public domain in countries and areas where the copyright term is the author's life plus 64 years at the most as of 2014. This work may also be in the public domain in countries and areas with longer native copyright terms that apply the rule of the shorter term to foreign works.