Is the Soncino 1961 translation in the public domain?
<p><a href="http://www.come-and-hear.com/copyright.html" rel="nofollow">Come-and-hear</a> (an anti-Semitic drivel website) has the full text of the 1961 Soncino translation of the Babylonian Talmud. They claim it is in the Public Domain since</p>

<blockquote>
  <p>The Babylonian Talmud: When Elizabeth Dilling published her book, The Plot Against Christianity, it contained hundreds of pages copied from the Soncino Talmud. In the 40 years since her book was published, Soncino Press has not ever pursued a copyright claim against her. Doubtlessly, Soncino understood that no serious religion would attempt to suppress discussion of their holy books in such a manner.</p>
  
  <p><strong>There is a principle in common law that, when private property is permitted for public use over an extended period of time, it cannot be thereafter be denied to the public. This principle is called public easement. In such manner have many trademarks passed into the public domain.</strong></p>
  
  <p><strong>In our case, however, the situation is even clearer. This Come and Hear™ presentation was created from the 1961 printing of the Soncino Talmud, which was published without copyright reservation.</strong></p>
  
  <p>Making portions of this work available on the World Wide Web is equivalent to displaying it on the shelves of a library open to the public. Our purpose is educational: we do not seek financial gain from the ingenuity of others. Moreover, our hypertext presentation cannot not be considered a replacement for the printed volumes. We recommend purchasing the original work — in the 1961 edition, if possible.</p>
</blockquote>

<p>Can works enter the Public Domain through repeated copyright violations?</p>

<p>No, repeated copyright violations do not cause a work to enter the public domain.</p>

<p>The first argument of public easement does not apply to copyright, and the comparison to trademarks is not appropriate. It is a feature of trademarks that they must be in use and enforced, otherwise the trademark may be lost. In turn, trademarks can be protected indefinitely. Copyright does not have this mechanism, and usually last the author's life plus 50 or 70 years, depending on the country. This is one reason why <a href="https://en.wikipedia.org/wiki/Orphan_works" rel="nofollow">orphan works</a> can be problematic.</p>

<p>The second argument is also generally not relevant. The <a href="https://en.wikipedia.org/wiki/Berne_Convention" rel="nofollow">Berne convention</a> requires that copyright is inherent, and needs not be registered or formally declared. This may be true, however, in countries that have not signed the Berne convention, like the <a href="http://www.wipo.int/treaties/en/notifications/berne/treaty_berne_121.html" rel="nofollow">U.S. before 1989</a>.</p>

<p>That said, the failure to pursue copyright claims might indicate they are not interested in applying the copyright, but the risk remains.</p>

copyright public-domain