1871, "Auf militairischen Befehl geoeffnet", small blue double-lined censor mark, both types, one on reverse of small envelope from Chambery (DEC 29, 1870) to Straßburg, the other one on reverse of folded letter from Olten, Switzerland (JAN 20, 1871) to Mulhouse. Both entires unfranked and charged with "30" resp. "50" centimes. A rare pair.
