cover 1871-72 (c.) pair of undated covers from the "Washburn" correspondence addressed to Constantinople, Turkey, the first from Middleborough, Mass. bears 1870-71 12c. mauve, the second with similar 10c. (after the August 1872 rate decrease), both show "KAISERLICH DEUTSCHE POSTAMT" c.d.s. on reverse, also weiterfranco accountancy marks