Australia. (via South America & Panama). 1857. Stamp-less envelope written from Melbourne dated 'September 18 1857' addressed to Boston, endorsed 'via Callao', erased and noted 'via Panama' with hand-struck 'Paid - To/ Panama' on face and circular 'Steamship/ 10' applied in New York.
Nice item from New South Wales sent via ship to Panama, carried across the Isthmus to Aspinwall and on 'USMSC' to New York.