Treasure Hunt 3

PHILIPPINES - USA, 1889 registered cover from Manila to St.Louis, franked with 8c oval overprint "Union Gral Universal" on 2 4/8c ultramarine (1st retouch), a horizontal strip of four all tied by Manila datestamp. Endorsed "via Hong Kong y San Francisco de California". On reverse REGISTERED / MAY 10 1889 / San Francisco, Cal. datestamp. Part top flap missing due to rough opening. Rare multiple usage of 8C stamp, paying triple rate Reg. Scott 105 (Photo)