I am keen to publish some scanned copies of railroad operation manuals produced by the International Textbook Press, Scranton, Pennsylvania. These would be on a personal web site but available to download by any interested visitors to the site. There are a variety of publication dates and my understanding, based on the Cornell copyright table, is as follows:
Published in the US with notice "Copyright 1922" but not renewed - in the public domain in the US by virtue of publication date.
Published in the US with notice "Copyright 1934, 1922" - still in the public domain in the US by virtue of original publication date.
Published in the US with notice "Copyright 1934" but not renewed - in the public domain in the US by virtue of non-renewal of copyright.
Published in the US with notice "Copyright 1934, 1924" - not in the public domain in the US until 2019 by virtue of renewal of copyright.
All copies also bear the notice "Copyright in Great Britain" but without specific dates. Assuming that copyright was effective from the dates of US copyright, UK copyright would apply until 70 years after the author's death.
Does that sound correct?