Oddly, John Newton Henderson had gone AWOL after he first joined the Navy and then enlisted again. I don't know if he really liked the Navy, felt an obligation to fullfill his original contract, or if the Navy finally found him and forced him back. Regardless, he joined as a Coal Heaver. The next place he shows up is as a stowaway on the SS Ludgate Hill, from London to NYC. He's listed as John Mix, brickmaker (which was his occupation in Philadelphia from city directories). Also on the list of stowaways is Henry W Lauer who also enlisted in the US Navy 17 Jan 1887 in Philadelphia. John Newton Henderson and Henry W Lauer apparently left the Navy as stowaways.
After John Newton Henderson returned to Philadelphia, he never used the name John N Mix again. The signatures of his enlistment and birth day match the same information as his marriage record to Susan McDevitt in Philadelphia 15 May 1893.