Cape of Good Hope 1876 "Tried Not Known" Advertised Unclaimed

1876 Blue envelope from Uitenhage (Barred Numeral BONC 14) to Cape Town. Endorsed in manuscript "Tried not Known" after initial Long Street address with manuscript suggestion "Try Loop Street" apparently unsuccessful. Cape Town arrival backstamp DE 29 75 and then further cds JA 1 76 ultimately receiving the backstamped ADVERTISED & UNCLAIMED GPO Cape Town mark of 28 1 76 (Goldblatt RLO 21). F-VF, interesting endorsed letter. See additional image.