Thomas Leavitt
... that Thomas Leavitt and his brother Martin patented the first practical device in the United States to machine postmark letters?
... that <b id="mwEDI"><a href="./Thomas_Leavitt_(inventor)" id="mwEDM" rel="mw:WikiLink" title="Thomas Leavitt (inventor)">Thomas Leavitt</a></b> and his brother Martin <a href="./Patent" id="mwEDQ" rel="mw:WikiLink" title="Patent">patented</a> the first practical device in the United States to <a href="./Machine_postmark" id="mwEDU" rel="mw:WikiLink" title="Machine postmark">machine postmark</a> letters?