cover 1902 (4 April) registered envelope from Djibouti to Perim bearing Obock 20c., 25c. and 25c. right-hand vertical bisect, cancelled by double-ring d.s. in blue and showing framed "R" with ADEN/REG." c.d.s. (R7.) on reverse; vertical filing crease not effecting adhesives. Unusual and attractive. Photo