Lot 52561861 (Jul. 16) Cambridge Mass. to Paris, France, forwarded to Freiburg, Saxony, cover bearing 10¢ green (35) strip of three cancelled by circular grids for double the 15¢ French mail rate (7½-10 grams), matching "Cambridge Ms., Jul 16" double-circle datestamp, red "Boston '24' Jul 16, 1860" credit exchange cds for French packet service, red Calais (7.28) entry cds ties strip and matching framed "P.D." handstamp; forwarded to Freiburg with red "Aus Frankreich, per Aachen, 29/7" exchange backstamp and blue manuscript. "2½" sgr due rating, German (7.30) arrival backstamp; small cover tear and wear, F.-V.F. and interesting forwarded use.
Estimate $200 - 300.
This cover was prepaid 30¢ under the 1857 US-France Convention at two-times 15¢ per 7½ grams. Forwarded under the 1858 France-Prussia Convention at 2½ sgr. per 10 grams, so letter weighed between 7½ and 10 grams.
Slow mid-19th century communications meant letters to intermediate destinations often arrived after the traveler had departed. Forwarders, banks and hotels sent them on to the next country as if they had originated there.