1864 (Aug. 17) Hamburg to Boston, Mass., folded letter with red "Hamburg Aug 17 1864" cds with attached "PD" and "16" schillinge prepaid treaty rating, magenta "Aachen 18/8 Paid 23 Cts." cds credit to U.S., carried by Cunard Line Europa from Queenstown Aug. 21 to Boston arriving Sep. 2, red "Boston Br. Pkt. Paid Sep 2" exchange cds, Very Fine. Estimate  $150 - 200. Aachen used magenta color for a brief period from about July 1864 to January 1865. Its use on this stampless Prussian Closed Mail cover is quite uncommon. $0 (Image)