Collection of mail box cancels of medallons

Quality: ✉

1857 N° 6 "10c. brown", letter envelope without contents, cancelled P.68-La-Louvière, fully margined, dated 9 April 1857, to Mons, letter box "D" in circle black, not described in "La Poste Rurale" for the 1850 period, though described for 1868 (Houdeng-Aimeries), one of the first letters with this letter box, vf