Mexico, S. L. Potosi, Abril, 11, 1864. Oval date stamp with matching "Franco" handstamp (Schatzkes 1446 & 1446A) on folded mourning letter sheet to Saltillo, "2" rate handstamp on reverse, S.L. Potosi (which was in conservative hands) sent to Saltillo which was in liberal area and did not recognize payment, with "2" due handstamp on front applied in Saltillo, Very Fine and choice, S.L. Potosi was out of stamps until April 16 when invoice #60 arrived. Estimate  $350 - 500. $0 (Image)