Weird Tales August 1931 renewed, so "The Whisperer in the Darkness" isn't clearable under PG Rule 6 without knowing if the copyright was sold to Weird Tales, or just publishing rights.
If you want to read something on the list posted by Smokestack then I'll save you the checking (twas tedious) there's two stories remaining as yet unrecorded: 'Poetry and The Gods' and 'Beyond The Wall of Sleep'. I think I shall have a pop at Beyond The Walls Of Sleep.
First recording for Libravox but I've used the software quite a bit before and shall watch out for format, DB, noise etc. I'll post it on 'Short Ghost and Horror Story Collection Vol. 013' when I'm done.
Mango.
As far as I can see, it was first published in Leaves, Issue 2 in 1938. It is very difficult indeed to prove that copyright was not renewed on particular articles in periodicals or on the periodicals themselves, and we have to err on the side of caution, I'm afraid.
Many thanks to Greg Weeks who has just got copyright clearance for the original Weird Tales version of The Dunwich Horror, and thanks to the PGDP volunteers who have transcribed it.