Prepayment of postage Dar es Salaam, impeccable letter the \"first German East African brewery WILHELM SCHULTZ, Dar es Salaam\", official seal \"Imperial German post office DAR. It SALAAM\" and red two-line cancel \"franked with 7 1/2 H\", cancellation \"Dar es Salaam c\", to Morogoro with arrival postmark, very interesting and rare