<A HREF="https://en.wikipedia.org/wiki/Charles_Sanders_Peirce">Charles Sanders Peirce</A> is credited with the <A HREF="https://en.wikipedia.org/wiki/Beth_number">beth notation</A>  ℶ, first introduced in a December 1900 letter to Cantor. Apparently, this was then forgotten for half a century.   
 I reproduce the relevant text from Gregory Moore's <A HREF="https://www.jstor.org/stable/41302100">Early history of the generalized continuum hypothesis.</A>

[![enter image description here][1]][1]    
[![enter image description here][2]][2]


  [1]: https://i.sstatic.net/ejfKA.png
  [2]: https://i.sstatic.net/qpKKb.png