The discovery of <a class="mw-redirect" href="https://en.wikipedia.org/wiki/Octonions" id="mwfA" rel="mw:WikiLink" title="Octonions">octonions</a> by <a href="https://en.wikipedia.org/wiki/John_T._Graves" id="mwfQ" rel="mw:WikiLink" title="John T. Graves">John T. Graves</a>, who denoted them with a boldface <b id="mwfg">O</b>, was announced to his mathematician friend <a href="https://en.wikipedia.org/wiki/William_Rowan_Hamilton" id="mwfw" rel="mw:WikiLink" title="William Rowan Hamilton">William Hamilton</a>, discoverer of <a class="mw-redirect" href="https://en.wikipedia.org/wiki/Quaternions" id="mwgA" rel="mw:WikiLink" title="Quaternions">quaternions</a>, in a letter on this date.<sup about="#mwt79" class="mw-ref reference" data-mw='{"name":"ref","attrs":{},"body":{"id":"mw-reference-text-cite_note-14"}}' id="cite_ref-14" rel="dc:references" typeof="mw:Extension/ref"><a href="./December_26#cite_note-14" id="mwgQ" style="counter-reset: mw-Ref 14;"><span class="mw-reflink-text" id="mwgg">[14]</span></a></sup>
<span class="mw-reference-text" id="mw-reference-text-cite_note-14"><cite about="#mwt76" class="citation book cs1" id="CITEREFSabadiniShapiroSommen2009">Sabadini, Irene; Shapiro, Michael; Sommen, Franciscus (2009-04-21). <a class="external text" href="https://books.google.com/books?id=H-5v6pPpyb4C&amp;dq=december%2026,%201843%20octonion&amp;pg=PA168" id="mwB0A" rel="mw:ExtLink nofollow"><i id="mwB0E">Hypercomplex Analysis</i></a>. Springer Science &amp; Business Media. <a class="mw-redirect" href="./ISBN_(identifier)" id="mwB0I" rel="mw:WikiLink" title="ISBN (identifier)">ISBN</a><span id="mwB0M" typeof="mw:Entity"> </span><a href="./Special:BookSources/978-3-7643-9893-4" id="mwB0Q" rel="mw:WikiLink" title="Special:BookSources/978-3-7643-9893-4"><bdi id="mwB0U">978-3-7643-9893-4</bdi></a>.</cite><span about="#mwt76" class="Z3988" id="mwB0Y" title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&amp;rft.genre=book&amp;rft.btitle=Hypercomplex+Analysis&amp;rft.pub=Springer+Science+%26+Business+Media&amp;rft.date=2009-04-21&amp;rft.isbn=978-3-7643-9893-4&amp;rft.aulast=Sabadini&amp;rft.aufirst=Irene&amp;rft.au=Shapiro%2C+Michael&amp;rft.au=Sommen%2C+Franciscus&amp;rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DH-5v6pPpyb4C%26dq%3Ddecember%252026%2C%25201843%2520octonion%26pg%3DPA168&amp;rfr_id=info%3Asid%2Fen.wikipedia.org%3ADecember+26"></span></span>